IISO 

'lHF tOr.KWOOD MEMO Hit·.l UBHAt{Y 
TM 5-625 
DEPARTMENT OF THE ARMY TECHNICAL MANUAL 
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REPAIRS AND UTILITIES 
SHEET METAL 

HEADQUARTERS, DEPARTMENT OF THE ARMY 

APRIL 1964 

AGO 8488A 
ACKNOWLEDGMENTS 
Acknowledgment is made to the following organizations and producers for permitting the use of certain illustrations and material in this manual: 
Aluminum Association, New York, N. Y. 
Aluminum Company of America, Pittsburgh, Pa. 
American Brass Company, Waterbury, Conn . 
American Iron and Steel Institute, New York, N. Y. 
American Zinc Institute, New York, N. Y. 
Chase Brass and Copper Company, Inc., Waterbury, Conn. 
Copper and Brass Research Association, New York, N . Y. 
Follansbee Steel Corporation, Follansbee, W. Va. 
International Kickel Company, Inc., New York, N. Y. 
National Lead Company, New York, N. Y. 
Revere Copper and Brass, Inc., New York, N. Y. 
United States Steel, Pittsburgh, Pa. 

TM 5-625 

T ECHNICAL MANUAL } HEADQUARTERS DEPARTMENT OF THE ARMY No. 5-625 WASHINGTON, D. C., 27 March 1964 
REPAIRS AND UTI UTI ES 

SHEET METAL 
Paragraph Page SECTION I. INTRODUCTION 
Purpose ------------------------------------------------------------------1 3 2 3
Scope ---------------------------------------------------------------------Safety --------------------------------------------------------------------
3 3 
11. TRADE PRACTICES 4 5
General -------------------------------------------------------------------
Shop layout ---------------------------------------------------------------5 5 Personnel -----------------------------------------------------------------
6 5 
Equipment ----------------------------------------------------------------7 6 Stock ---------------------------------------------------------------------
8 7 
9 10 Fire prevention and other shop precautions____________________________________ 10 11 
Shop practices -------------------------------------------------------------
III. MATERIALS AND METHODS 
11 11
General -------------------------------------------------------------------
12 13
Copper -------------------------------------------------------------------
13 15 Nickel-copper alloy (monel)--------------------------------------------------14 17 15 18 
Aluminum -----------------------------------------------------------------
Brass ---------------------------------------------------------------------16 19
Lead ----------------------------------------------------------------------
Galvanized iron and steeL____________________________________________________ 17 20 18 22
Zinc ----------------------------------------------------------------------19 22
Terne plate ---------------------------------------------------------------Corrosion-resisting (stainless) steeL__________________________________________ 20 23 
21 26
Black iron -----------------------------------------------------------------Miscellaneous materials ----------------------------------------------------
22 27 Mastics and calking compounds _____________________________________________ _ 
23 28 
IV. JOINTS AND FABRICATION 
> 
24 28
General -------------------------------------------------------------------25 29
Mechanical fasteners -------------------------------------------------------26 32
Soldering -----------------------------------------------------------------27 34
Brazing ------------------------------------------------------------------28 34
VVelding -------------------------------------------------------------------Joints 29 35 30 37
Seams ---------------------------------------------------------------------
V. 	INSTALLATION, MAINTENANCE, AND REPAIR 31 43
Expansion joints -----------------------------------------------------------
Corfiices and belt courses __________________________________________________ _ 

32 43 33 46
Flashings -----------------------------------------------------------------34 61
Roofing --------------------------------------------------------------------Gutters 35 67 
TAGO 8488A-March 

Paragraph P a g e 
Leaders (do~nspouts) ------------------------------------------------------36 69 
Splash pans and splash b:ocks _______________________________________________ _ 
37 72 
Scuppers and roof drain~----------------------------------------------------38 72 39 73
Scuttles -------------------------------------------------------------------Radiator recess linings-------------------------------------------------------40 73 41 73
Sno~ guards --------------------------------------------------------------42 74
Roof ventilators ------------------------------------------------------------
Smoke jacks and breaching __________________________________________________ 
43 74 44 75
Air movers ---------------------------------------------------------------
~aintenance of roofs and flashing ____________________________________________ 
45 75 46 79
Duct~ork -----------------------------------------------------------------
linings and pans____________________________________________________
Sho~er 
47 81 48 81
Range hoods and canopies--------------------------------------------------49 83
~edical X-ray protection----------------------------------------------------
85
APPENDIX I. REFERENCES -----------------------------------------------------------
11. SELECTION OF ~ATERIAL. (TABLES 9, 10, AND 11) --------------------88 
91
GLOSSARY----------------------------------------------·----------------------------------INDEX____________________________________________________________________________________ 
93 
AGO 8488A 
Section I. INTRODUCTION 
I. Purpose 

The purpose of this manual is to provide personnel concerned with a guide to the materials, performance, and standards used in sheet metal shops. The text has been arranged for practical and concise reference to provide guidance for maintaining, repairing, replacing, and installing sheet metal items in buildings and structures. 
2. Scope 

This manual describes materials, equipment, and methods used to fabricate, repair, replace, and install sheet metal items. The manual is divided as follows. 
a. 
Section I gives the introduction to the manual and includes basic safety precautions to be followed when handling sheet metal. 

b. 
Section II covers the standard trade practices and equipment used in sheet metal shops. 

c. 
Section III lists the various sheet metals and describes their characteristics, uses, maintenance, and unusual properties peculiar to each metal. 

d. 
Section IV outlines the various methods used to join sheet metal together. 

e. 
Section V covers the installation, maintenance, and repair of sheet metal in specific applications. 

f. 
Appendixes are included in the back of the manual containing supplementary information in the form of tables and charts. A list of reference publications is included. 


3. Safety 

a. Safety is a primary consideration to which all personnel should devote their conduct and attention (par. 10). All safety requirements of TM 5-610 and of the installation commander will be observed. The tools and equipment used in handling and working sheet metal are dan-
AGO 8488A 
gerous because of the nature of the work and should not be used by inexperienced personnel. Sheet metal itself is dangerous because of its physical properties and chemical composition. The edges and corners can easily inflict injuries, and many metals or their protective coatings are toxic and can cause serious infections or blood poisoning. Fumes generated by the burning of flux and protective coatings during soldering, welding, and cutting operation are often toxic. Many causes of accidents are illustrated in figure 1. 
b. The following precautions should be observed when operating equipment and working with sheet metal: 
(1) 	
Jewelry and loose clothing should not be worn. 

(2) 	
Goggles and gloves should be worn during welding and grinding operations. 

(3) 	
Treat all cuts, scratches, and burns immediately to prevent infection and possible blood poisoning. 

(
4) 	Protect uncovered skin when handling acids. When diluting acids, always pour acid into water, never water into acid. Keep acids in closed, sealed, clearly labeled containers. 

(
5) 	Power tools should ony be operated by experienced personnel. 

(6) 	
Power equipment should have safety guards in place at all times. 

(7) 	
Have both hands free when ascending or descending a ladder. Transfer tools and equipment with a rope or similar device. 

(8) 	
Use only the safest solvents available for the work to be done. 

(9) 
Welding, 	soldering, and burning should only be done in well ventilated areas and away from flammable liquids and materials. 





BE ALERT AND PAY 
ATTENTION TO THEJOB 

IWEAR GLOVES F(t'>. HANDLING SHARP EDGES 
KEEP SHOPS NEAT 
AND ORDERLY 

GET INSTRUCTION 
HOW TO OPERATE 

KEEP FLOORS AND 
GROUND CLEAR OF TRASH 

KEEP SHARP TOOLS 
OUT OF POCKETS 

REPORT ALL DANGERS 
\ PAY ROU / 
~
• 
"'-.) 
... AND ALWA'(S
CLIMB SAFELY USE. SAFETY DEVICES 
BE SAFET'( CONSCIOUS 
Figure 1. Precautions that reduce accidents. 
AGO 8488A 
Section II. TRADE PRACTICES 
4. General 
This section covers the standard trade practices with respect to shop layout, equipment, personnel, and stock. 
5. Shop layout 
a. 
The layout of any shop depends upon the available space and required equipment; therefore, set r ul es cannot be established for the positioning of equipment (TM 5-611 and AR 415-31). A typical sheet metal shop layout is shown in figure 2. Other shop layouts are shown in TM 5-611. 

b. 
The folowing r ules are recommended when laying out a sheet metal shop: 


(1) Place the equipment in a logical order coinciding with the progression of the work. The storage area should be located out of the way and preferably in an adjacent room. Pattern tables, slitting shears, and planning area are located adjacent to the storage area to eliminate the necessity of moving large sheets of metal through the shop. Brake, folding, edging, and rolling machines should be located in the same area to keep t he actual metal working confined to one area. The remaining equipment is located for 
convenience and accessibility. 
(2) 	
Welding equipment is a safety hazard both to property and personnel. Such equipment should be locat ed in a well ventilated area away from flammable materials and liquids. The area or equipment should be shielded to protect personnel from the intense heat and light generated during welding operations. 

(3) 	
Workbenches should be placed where there is the least activity. Machinery and cutters located near workbenches create a safety hazard t o personnel working at the benches. 


6. Personnel 
The sheet metal force usually consists of a sheet metal foreman and an adequate number 
50'+------------------------------------~ ~---------------------------
NEW 
\1) WORK
SHEET 	SINk 
~ BENCH
METAL 
\) 
STORAGE~ 
ll 
SQUARE 	L AYOf.IT 
SHEARS Isuri TABLE 	OLDEI/A/6 
u 
BENCH li-
SHEARS 
....
L__j 
0 
C"r) 
MACHINE SPOT
' 
c 	n D
BENDING BRAI<E 
m LOCk uR OLLERS WELDER 
Figure 2 . Typical sheet metal shop. 
AG O 8488A 
of mechanics and helpers. The sheet metal foreman must know sheet metal practices and such regulations as apply to it. He should be able to design and layout all types of sheet metal work and have the experience required in the trade as a foreman. The duties of the sheet metal foreman include the planning and direction of activities and the delegations of duties for each man in the organization. In addition, the sheet metal foreman is responsible for the safety of all personnel and equipment under his supervision. Sheet metal mechanics m st be able to lay out, makeup, and install all types of sheet metal work in normal use. Sheet metal helpers should have experience as apprentices in the sheet metal trade. 
7. Equipment 

The tools and equipment used in sheet metal shops can be divided into two categories; handtools and shop machinery. 
a. Handtools. The majority of sheet metal work accomplished involves the use of handtools. For efficient operation all tools must be kept in good working condition, stored in an accessible place, and returned after being used. Figure 3 illustrates good shop practice in keeping tools orderly and accessible. 
Common sheet metal handtools (fig. 4) include: 
(1) 	Awls or scribers for marking lines on metal. 
Figure 3. Sto1·ag e of handtools . 
(
2) Dividers for marking arcs and circles, and to transfer a line length from one object to another without the use of a ruler. 

(
3) 	Squares for laying out 90o at corners. 

(
4) Protractors for determining and laying out angles. 

(5) 	
T r ammel points or beam compasses for drawing large circles or arcs. 

(
6) Rulers for determining linear measurement. 

(7) 	
Sheet metal gage for determining the thickness of sheet metals in gage numbers. 

(8) 	
Micrometer for measuring sheet metal thickness. 

(9) 	
Punches in all types. (Special punches are designed for locating holes, center punching a mark for drilling a hole, and punching holes in sheet metal. 

(10) 	
Grooves available in many types and sizes, used for forming and locking seams by hand. 

(11) 	
Rivet sets for setting rivets and forming the finished rivet head. 

(12) 	
Chisels available in various sizes and shapes, used to cut small metal projections (screws, rivets, etc.) and grooves or slots in large pieces of metal. 

(
13) 	Hammers in various sizes and shapes for particular jobs. (Be sure the correct hammer is being used. Types of hammers include chipping, ball peen, riveting, setting, raising, and common or clawhammer.) 

(14) 	
Mallets made of wood (usually hickory), fiber, leather, or hard rubber, used in place of metal hammers to prevent damage or defacing metals. 

(15) 	
Snips for cutting sheet metal, available with shaped cutting edges to facilitate cutting circles, S-curves, straight lines, and curves. 

(16) 	
Pliers for gripping and working sheet metal. 

(17) 	
Tongs (adaptations of pliers with wide jaws) used to form and lock seams along the edges of metal sheets. 


AGO 8488A 


(18) 	
Coppers (soldering irons) are pieces of copper of various sizes and shapes attached to insulated handles. (Coppers are heated in small furnaces and supply the heat for soldering) 

(19) 	
Hacksaws for cutting metal too heavy for shears where a smooth and accurate cut is required. 

(20) 	
Files of various sizes, shapes, and degrees of roughness to fit all surfaces and give the proper cutting action. 

(21) 	
Stakes available in many sizes and shapes to form sheet metal to the desired shape of the end item. (Stakes are secured in metal bench plates specifically designed to fit stake shank.) 


b. Shop Machinery (fig. 5). Shop machinery includes both manually operated and power driven equipment. Sheet metal personnel should be thoroughly familiar with all types of equipment and trained in its operation. Inexperienced personnel should be warned against the unsupervised use of machinery both as protection to the personnel and to prevent damage to the equipment. Shop machinery includes, but is not limited to, the following: 
(1) 	
Bar folder. Bands edges of 22 gage or lighter metals. 

(2) 	
B eading machine. Forms a bead around the edges of 22 gage or lighter metals. 


(3) 	B ending brake. Forms bends in 18gage and lighter metals. 
(4) 	Burring machine. Turns burrs on circular disks and prepares sharp folds or edges of cylindrical articles. 
(5) 	Crimping and beading machine. 
Crimps and beads the edges of metal sheets in one operation. 
(
6) Drills . Both portable electric drills and drill presses are used to drill holes in heavy gage metal. 

(7) 	
Edging machine. Forms a border or edge along the edges of sheet metal. 

(8) 	
Forming machines . Forms sheets into curved or cylindrical shapes. 

(9) 	
Grooving machine. Shapes the edges of sheets for grooved seams and is extensively used for longitudinal seams or cylinders. Lock rollers are forms 


AGO 8488A 
of grooving machines designed for developing the various roofing seams, drive cleats, and the Pittsburgh lock seam. 
(10) 	
Shears. Special shears for slitting sheets, squaring edges, and cutting arcs or disks. 

(
11) 	W elding equipment. Generally the only welding equipment found in a sheet metal shop is a spot welder. Equipment for continuous arc welding and brazing is usually confined to machine shops. 

(12) 	
Misc ellaneous equipment. Many varieties of the above equipment are designed for specfic operations rather than general purpose use. Examples of these machines would be brakes designed for forming the Pittsburgh lock seam, gutter beading machines, and double-seaming machines for double seaming flat battens. 


c. On-the-Job Equipment. Set rules for what equipment should be carried cannot be established because of the variety of jobs encountered; therefore, it is up to the judgement of the foreman and sheet metal mechanics who plan the job to determine the necessary tools and equipment required to complete the work. All items and seams that can be fabricated in the shop should be completed before going out on the job to keep on-the-job time at a minimum. 
8. Stock 
The thickness and types of sheet metal carried in stock is governed by types used in original construction, experience with the particular location, and guideE established herein. Shop stock and warehouse stock levels are established by the Post Engineer based upon recommendations of shop foremen and instructions received from higher headquarters. An adequate supply of stock should be kept on hand at all times; however, excessive quantities should be avoided. New sheet metal should be stored in racks as shown in figure 6. A second rack should be provided for cut piecses. Use of cut pieces should be encouraged whenever possible. Common metals that should be kept in stock include: 
a. Copper. Copper is the most common sheet metal used for roofing and sheet metal work. 

HANDY SEAMER 
HAND GROOVER 
<~ 
SQUARE POINT SOLDERING COPPER 
~~ 
ROOFING COPPER 
D ...... ,C..J > 
BOTTOM COPPER 
;.> 
G) 0 
~ 
00 00 
;.> 
BENCH 
~ 
AV~~:N t -p 
WING DIVIDERS 
COMBINATION PLIERS 
0
COMBINATION
-
(SUP JOINT) c:::::::=: '.·. 
-.:::·::::::-···~<:: .. J:J 
CENTER PUNCH 
E::?!23:=o~ ~ 
SNIPS OR SHEARS 
STEEL SQUARE 
[} J 
HOLLOW PUNCH
Fi 
BEAKHORN
'MALLET 
ill CANDLEMOL~ 
NEED~ 
RIVETING HAMMER 
~ 
I Cl=\
CJ fC3 a 
0 D 0 0 = ~ = c:=1 =o.~O = 
I 
~~ 
BENCH PLATE 
STAKES AND HOLDER 
Figure 1,. Common handtools. 
BENDING BRAKE 
SPOT WELDER 
LOCK ROLLER AND GROOVER LIGHTENING SLIP ROLL FORMER
DRILL 
BURRING AND EDGING 
CRIMPING AND BEAD ING BAR FOLDER 
Figure 5. Typical shop machinery. 
Three, six, sixteen, twenty, twenty-four, and c. Galvanized Iron. Sheets of galvanized iron forty-eight ounce copper sheets are most freshould be stocked for repair to ductwork and quently used. 
other items commonly constructed of galvanized 
b. Brass and Bronze . Brass and bronze are 
iron. Sheets lighter than 26 gage are seldom
used in small quantities usually in strip bar or 
plate form. used and corrugated sheets are generally re

Heavier gages should be stocked in small quantites. placed in large quantities and should be requi-
AGO 8488A 
f"TT_ 
"" 
r"' 
v ~ 
v ~ 
v ~ 

v i/ 
NEW PIECES CUT PIECES 
Figure 6. Storage of sheet metal. 
sitioned for the specific job rather than carry large quantites in stock. 
d. 
Aluminum. Aluminum is used extensively for roofing, siding, flashing, and miscellaneous uses; 0.032 inches thick is used extensively and should be kept in stock. 

e. 
Corrosion-Resisting (Stainless) Steel. Corrosion-resisting steel is used to fabricate many items and should be kept in stock. Type 302 (SAE 30302 or 18-8 composition) is the most versatile of the stainless steels. For miscellaneous uses 20-to 28-gage sheets should be stocked. For trim, wall and door coverings, and similar applications 10-to 18-gage sheet.s should be used. 

f. 
Miscellaneous Metals. Various metals such as lead, zinc, coated and clad metals, and special alloys have specific uses and are not necessarily carried in stock unless there are sufficient applications to warrant their use. 


9. Shop Practices 
All materials and labor are accounted for (AR 420-17) either on DA Form 2700 (Individual Job Order), DA Form 5-79 (Standing Operation Order) , or a Maintenance Service Order (for small maintenance jobs) . 
a. Planning . Upon the receipt of an approved work order, the foreman requisitions materials not in shop stock from the warehouse on authority of the work order, and delegates the work to his sheet metal mechanics. 
b. 
Layout. The necessary patterns are developed or selected if available. Patterns for common items are generally transferred to a durable material like stiff cardboard, fiberboard, or sheet metal, and cut out to facilitate repeated usage. For convenience, the patterns should be labeled, indexed, grouped, and stored in such a way as to be readily selected as illustrated in figure 7. Permanent patterns are laid on the sheet metal and the pattern transferred to the sheet metal by tracing around the edges with scribers. Temporary patterns or drawings are laid on the work over carbon paper. A pencil or other sharp object is traced over the pattern and the image is transferred to the metal through the carbon paper. 

c. 
Fabrication. The sheet metal is cut conforming to the pattern and processed through the necessary machinery for forming, seaming, and edging. Soldering and spot welding are completed in the sheet metal shop but quite often the item is sent to a machine shop for brazing and welding and to a paint shop for the prime or final finish. 

d. 
Installation. Installation is performed by the sheet metal mechanics and helpers. To eliminate unnecessary delays at the job, the sheet metal mechanic should have the work planned and the necessary tools and equipment for completing the job before leaving the shop. 


AGO 8488A 



Figure 7. Storag e of patterns 
I0. Fire Prevention and Other Shop Precautions 
Workshops by their nature are potential fire and safety hazards. Shop personnel must know and comply with all fire prevention measures as issued by the installation fire marshal. Personnel should be familiar with all available fire fighting apparatus, evacuation procedures, and safety practices. The following precautions should be observed at all times. 
a. Flammable liquids must be kept covered when not in use, and when used they must be kept away from fire, flame, and sparks. Fumes from flammable liquids are often toxic and explosive, and their use should be restricted to well-ventilated areas. Wherever possible use nonflammable and nontoxic solvents for cleaning. 
b. 
Rags contaminated with oil and grease must be cleaned or destroyed daily to prevent spontaneous combustion or accidental ignition. 

c. 
Machinery and surrounding areas must be kept clean and free of metal shavings and trimming. Oil and grease dripping from machinery accumlates in dirt and metal filings creating a fire hazard. Metal trimmings and pieces of scrap metal present a safety hazard to personnel. 

d. 
Tools and equipment should be returned to the racks and containers provided for them. Cluttered work areas increase the working time of a job, subject tools and equipment to abuse, and create a safety hazard. 

e. 
Safety precautions outlined in paragraph 3 for personnel safety should be followed by personnel handling sheet metal. 

f. 
Provisions should be made for collection and disposal of scrap metal. Adequate bins should be placed near cutting and trimming machines and workbenches. 


g . Gas and gasoline heaters are a constant source of danger. Soldering iron heaters should be turned off when not in use. The odor of gas or gasoline around heaters indicates the presence of a leak. All sources of ignition must be eliminated until the leak is repaired. 

h . Hot soldering irons are a potential fire and safety hazard and must not be placed on flammable materials or where personnel can accidentally come in contact with them. Stands or holders should be provided for hot soldering irons. 


Section Ill. MATERIALS AND METHODS 
II. General 
The wide variety of sheet metals available present a problem in determining the proper material for the various jobs encountered. This section is devoted to the various sheet metals available and outlines their characteristics, uses, physical properties, and peculiarities. Sheet metal selection tables are furnished in appendix II for quick and comparative reference with respect to characteristics and uses of the sheet metals. The following discussion outlines the general characteristics of sheet metals. 
AGO 8488A 
a. Base M etals a.nd Alloys . Base metals are elements that in their pure state have a metallic nature and when prepared for use, are chemically or "commrecially" pure. Base metals are combined with other metals or chemicals to produce metals having special properties. Such metals are known as alloys and include metals like brass, steel, solder, and monel. Another distinction is made by dividing metals into two groups; ferrous metals are alloys utilizing iron as the base metal ; nonferrous metals are base metals and alloys that contain little or no iron. 

b. Thickness of Sheet Metals. The thickness of metal sheets is determined by gage, decimal fractions of an inch, weight per square foot, or a combination of two methods. Two scales of gage thickness are commonly used ; the Brown and Sharpe or American Standard for nonferrous wire and sheet metal; and the United States 
Standard for iron and steel plate. Table I lists the common gages of sheet metal with the decimal equivalent for each standard. The weight per square foot system is commonly used for nonferrous metals with nonuniform thicknesses within a single sheet, and the thickness for each weight varies with the different metals. A combination of two systems is used for clad metals where the base sheet is measured by gage number and the protective coating is measured in weight per square foot. An example of this would be galvanized iron where the black iron sheet is generally 26 gage coated with 1.25 ounces of zinc per square foot. The thickness of sheet metal is measured with either a slotted metal gage or a micrometer. The number of the slot into which the metal fits snugly without forcing indicates the gage of the metal. Micrometer readings should be taken at intervals to determine the average thickness of the sheet. Micrometer readings are in decimal fractions of an inch and can be converted to the nearest gage number by using table 1, or weight per square foot by referring to the tables pertaining to the specific material being measured. 
c. Coeffici ent of Expansion. Changes in temperature cause expansion and contraction in all metals. The actual linear movement varies with each metal as shown in table 2. This thermal movement must be taken into consideration when sheet metal is installed to allow 
sufficient clearances to compensate for the change. Buckling of sheets, tearing at seams, loosening or pulling through of fasteners are common failures caused by inadequate provisions for expansion and contraction. Table 2 can be used to compute the thermal movement for the common metals. Clad metals have the same coefficient of expansion as the base sheets. 
d. Wor kability. Workability of metals generally depends upon their hardness and ductility. 
The hardness regulates the equipment needed to work the metal, and the ductility governs whether the metal can withstand bending without fatigue or fracture. Sheet metals are commonly joined by seams and worked into shapes, and are therefore produced in a condition that possesses good working qualities. 
Table 1. Sheet Metal Gages * 
Brown & Sharpe or 
Ga ge No.  American standard for no nfe rrous wire and sh eet m etal  United States st a nda rd for iron and st eel plate  
0000000  ---- 0.5000  
000000  0.5800  0.4688  
00000  0.5165  0.4375  
0000  0.4600  0.4063  
000  0.4096  0.3750  
00  0.3648  0.3438  
0  0.3249  0.3125  
1  0.2893  0.2812  
2  0.2576  0.2656  
3  0.2294  0.2500  
4  0.2043  0.2344  
5  0.1819  0.2188  
6  0.1620  0.2031  
7  0.1443  0.1875  
8  0.1285  0.1719  
9  0.1144  0.1562  
10  0.1019  0.1406  
11  0.0907  0.1250  
12  0.0808  0.1094  
13  0.0720  0.0938  
14  0.0641  0.0781  
15  0.0571  0.0703  
16  0.0508  0.0625  
17  0.0453  0.0562  
18  0.0403  0.0500  
19  0.0359  0.0438  
20  0.0320  0.0375  
21  0.0285  0.0344  
22  0.0253  0.0312  
23  0.0226  0.0281  
24  0.0201  0.0250  
25  0.0179  0.0219  
26  0.0159  0.0188  
27  0.0142  0.0172  
28  0.0126  0.0156  
29  0.0113  0.0141  
30  0.0100  0.0125  
31  0.0089  0.0109  
32  0.0080  0.0102  
33  0.0071  0.0094  
34  0.0063  0.0086  
35  0.0056  0.0078  
36  0.0050  0.0070  
37  0.0045  0.0066  
38  0.0040  0.0063  
39  0.0035  ---- 
40  0.0031  ---- 

* Dtmens ion s in dec imal pa rts of a n in ch. 
AGO 8488A 
Table 2. E xpansion and Cont?·action 
Linear movement per 
l 50 °F. change 
thermal expan-per 8 feet 
Metal sian (inches 
per inch per 
Coefficient of 
Fraction (i n .) degree F.0 Deci mal (in.) (approximate) 
Steel Med -------0.0000067 0.0965 %+ Iron-wrt 0.0000067 0.0965 %+ Monel 0.0000077 0.1109 %4 Copper 0.0000093 0.1339 %+ Brass 0.0000104 0.1498 1%4 Aluminum -------0.0000128 0.1843 1%+ Lead 0.0000162 0.2333 1%+ Zinc 0.0000173 0.2491 1%-t 
e. ElectTolysis. Electrolysis is the term used to describe a galvanic action that occurs when two dissimilar metals come in contact with an electrolyte. In a galvanic action, one metal forms ions with the electrolyte which, in turn, causes an electro-chemical reaction which decomposes the other metal. The more common metals in the electro-chemical series are listed in table 3. When any two of these metals come in contact with each other and an electrolyte, the metal with the lower number will corrode. The galvanic action increases as the metals are farther apart in the series while metals close together, like lead, tin, and copper, are not seriously affected. 
(
1) A void the use of dissimilar metals where exposure to water, moisture, and acids is probable. In structures, the roofing, siding, flashing, gutters, downspouts, and fasteners should be of the same material. When the use of dissimilar metals is unavoidable, electrolysis can be prevented by the use of insulator strips of asbestos, sheet lead, moisture-resistant building felt, heavy coating of asphalt paint, and galvanizing ferrous metals. 

(2) 	
Asbestos, sheet lead, or building felt is used to prevent direct contact between two metals. Asphalt paint and building felt are used to cover nonmetallic surfaces before applying sheet metal, or to cover exposed sheet metals 

(usually copper) to prevent the destruction of a nearby dissimilar metal. 

(3) 	
Galvanic action between two metals can be retarded or stopped by the addi


tion of a third metal with a number lower than the metals to be protected. Zinc is usu'<illy used for this purpose. The potential between zinc and the other metals is sufficient to transfer the galvanic action to the zinc. In this reaction the zinc is decomposed and the other two metals are left unharmed. 
(4) 	A good example of electrolysis is the use of a galvanized iron gutter with a copper roof. The rain flows over the copper roof and picks up copper ions. The contaminated water drains into the galvanized iron gutter and the copper ions react with the zinc coating which decomposes. As long as part of the zinc coating is in the gutter, the reaction will be with the zinc and the iron will not be seriou1?1Y damaged. However, when the zinc is depleted, the iron will corrode through in a few months. Obviously, the solution to this problem would be to install copper gutters and downspouts. 
Table 8. Electro-Chemical Series 
No 1-Aluminum No. 5-Nickel No. 2-Zinc No. 6-Tin No. 3-Steel No. 7-Lead No. 4-Iron No. 8-Copper 
12. 	Copper 
Copper (Fed. Spec. QQ-C-576) is one of the common metals used in buildings and structures. The factors governing the use of copper ar e durability, decorativeness, and cost. Copper is highly corrosive resistant and is used on buildings and structures where permanence is desired and where high concentrations of industrial fumes render the atmoshpere corrosive. Lead coated copper is installed to prevent copper staining on the sides of structures or to protect dissimilar metals in the construction below. However, on many monumental buildings the copper is left bare to form an oxide with the atmoshpere known as patina (d(3) below) . The cost of copper is high compared to ot her materials and must be considered to be sure the job warrants its use. 
a. T empe1·. (See glossary) Copper sheet metal is produced in varying degrees of hardness, but 
AGO 8488A 
is generally divided into two gro ps that are best suited for general purpose work in srtuctures. "Soft" is the term given to soft rolled, hot rolled, or roofing temper and is used for standing and batten seam roofing, caps, and through-wall flashings. "Cold rolled" is the term given to hard, hard rolled or cornice temper and is recommended for most general purpose construction work, especially base and counter flashings, gutters, downspouts and other places where stiffness is required to support or maintain the shape of an item. 
b. Thickness. Thickness of copper sheets is 
measured by the American Standard for nonferrous wire and sheet metal gage and in ounces and pounds per square foot. The ounce per square foot system is generally used. Copper sheets with a thickness greater than ~~ 6 inch are classified as plates. Table 4 lists the common weights of copper in ounces or pounds per square foot and its equivalent thickness. Each increase of 2 ounces increases the thickness of the sheet 0.0027 inches. This thickness is the average thickness of the sheet and will vary ± 0.003 inches. 
Table 4. Thicknes.~ of Copper Sheets 
Weight per square foot (in ounces)  Thickness; dec imal equivalent (in inches)  Weight per square foot  Thickness; decimal equivalent (in inches)  
10 ------- 0.0135  38 oz  0.0513  
12 ------- 0.0162  40 oz  0.0540  
14 ------- 0.0189  48 oz  0.0648  
16 ------- 0.0216  4 lb  0.0864  
18 ------- 0.0243  5 lb  0.1080  
20 ------- 0.0270  6 lb  0.1296  
22 ------- 0.0297  9 lb  0.1944  
24 ------- 0.0324  25 lb  0.0431  
26 ------- 0.0351  30 lb  0.0539  
28 ------- 0.0378  35 lb  0.0593  
30 ------- 0.0405  40 lb  0.0701  
32 ------- 0.0432  50 lb  0.0863  
34 ------- 0.0459  55 lb  0.0972  
36 ------- 0.0486  60 lb  0.1030  

c. Characteristics. 
(1) 	Durability. Copper has the necessary qualities to resist corrosion from air, water, and weak acid solutions that develop in the atmosphere. Being a soft metal, copper is subject to erosion or wearing away due to abrasive action. Copper is considered a permanent metal in buildings and structures, and several structures in existence today have copper roofing, flashing, and trim 
that are still serviceable after centur
ies of use. 
(2) 	
WoTkability. Copper is soft and ductile permitting the use of all types of seams for joining and folds for forming operations. Cold working hardens copper. Repeated folding, bending, or hammering should be avoided or the copper must be annealed to restore its ductility. 

(3) 	
ElectTolysis. Because of its position in the electro-chemical serias (par. lle), copper is seldom damaged by galvanic action. However, the presence of copper can electrically corrode other metals if insulation or other precautions are not used. 

(
4) 	Toxicity. Copper is toxic and should not be used where food is handled. Wounds caused by copper should be treated immediately to prevent infection and possibly blood poisoning. Food should not be handled after working with copper without first washing the hands. 


d. Installation. 
(
1) 	Surface preparation. The surface receiving copper must be smooth to prevent excessive stress or wear at high spots. When copper is laid over concrete, a wash of cement or coat of bituminous plastic cement (Fed. Spec. SS-C-153) can be used to smooth the surface. Waterproofed building paper 

(Fed. Spec. UU-P-147) is placed over the concrete or bituminous cement before laying the copper. Building paper or felt should always be used under copper roofing. 

(2) 	
Fasteners, seams and joints. All mechanical fasteners (par. 25) should be made of copper. Cleats are generally used to secure sheets of copper. Copper is ductile which permits easy forming for various types of seams for joining. For water tight joints, copper is readily soldered or brazed 


(par. 26 and 27). For water tight joints as in roofing where freedom of movement is desired, paste sealers or 
AGO 8488A 
expansion joints are recommended. Two types of sealers are commonly used; a paste containing 92 percent lead carbonate and 8 percent linseed oil or a mixture of asphalt and asbestos fiber (Fed. Spec. SS-C-153) . The lead paste is usually specified. 
(3) 	Protective Coatings. Exposed copper oxidizes and forms a green coating known as "Patina". This coating is harmless and acts as a shield against further deterioration. However, water dripping from copper construction produces a stain that is difficult to remove. The building shown in figure 8 illustrates the effects of "copper staining." Where water is permitted to run off copper and onto surfaces that would be defaced if stained, the copper should be lead coated or painted 
(TM 5-618). The lead coating serves as a sealer to prevent staining of surrounding material and as a base surface for paint. When painting is required, the surface must be cleaned with a 5 to 10 percent solution of washing soda to remove all flux and foreign matter, and then be given a wash primer (Mil C-14504 CE) prior to the application of paint. 
e. Maintenance. Copper normally requires little or no maintenance. However periodic inspecitions should be made to check for the following: 
(1) 	Seams for cracks, broken solder, or missing sealer. 
(2) 	
Buckling or creases which could lead to metal fatigue. 

(3) 	
Fasteners for corrosion, looseness, and enlarged holes around nails, screws, and rivets. 

(
4) 	All work should be inspected after extreme temperature changes and rain or wind storms to detect damage or faulty construction. 


f. Reuse of Copper. The reuse of copper is r ecommended because of its high cost and duct ility which permits reworking. However, care must be exercised to prevent metal fatigue where the metal was previously creased or stressed. 
13. 	Aluminum 
Aluminum (Fed. Spec. QQ-A-359) is a nonferrous metal refined by chemical and electrolytice processes from bauxite ore. The basic factors which determine the use of aluminum are light weight, ductile, nontoxic and partially corrosion resistant. The users of aluminum include flashing, roofing, gutters, downspouts, siding, ductwork, ventilators, screens, and louvers. 
a. 
Temper. Various degrees of hardness are obtained by cold-working, heat treatment, or the addition of other chemicals to form alloys. For general construction work, aluminum is classified as soft or hard. The letter A (commercially 0) denotes soft and the letter H denotes hard. 

b. 
Thickn ess . The thickness of aluminum sheets is usually measured in decimal fractions of an inch as opposed to a gage number or weight measure. When gage is referred to it is the Brown and Sharp (American Standard) System. Sheet thicknesses vary from 0.016 inch to 0.125 inch, but in special cases these limits are exceeded to include foil and plates. 


c. Characteristics. 
(1) 	Durability. Aluminum is resistant to atmospheric corrosion, most neutral salts, organic acids (except formic, oxalic, and trichloroacetic acids) , many organic solvents and dry gases. It is highly resistant to ammonia and ammonium hydroxide. Aluminum is generally attacked by acid and alkaline salt solutions, sodium and potas-
Figure 8 . Typical example of copper staining. 

sium hydroxide solutions, mineral the heat is spread rapidly and evenlyacids such as halogen acids, and interover the surface eliminating "hotmediate concentrations of nitric and spots". Use of aluminum electricalsulfuric acids. wiring is limited because of alum
(2) 	WoTkabi lity. Aluminum is ductile inum's poor adhesion to solder andand will withstand a 180° bend withrapid work hardening property.out fracture. Cold working rapidly ( 6) M'iscellaneous. Other properties andhardens aluminum; therefore straightcharacteristics influencing the use ofening, refolding or reworking will aluminum for special jobs areusually fracture the affected area. To (cL) Nonsparking for use around flamtrim light gauge soft temper corru
mable liquids and explosives.
gated aluminum perpendicular to cor
(b) 	Acoustically dead ( i.e., high degreerugations, scribe deeply, and tear by 
of 	sound absorption) for soundforceful rolling of cutoff portion. 
proofing or absorbing shock" or vi
(3) 	ElectTolysis. Aluminum is the most 
brations which could develop sound.
active of structural metals and decom
d. Installation.
poses rapidly when in contact with
other metals. Extra precautions must (1) 	Su1"[ace pre pam tion. Direct contactwith mortar, lime, cement, and wood
be taken when aluminum is exposed toother metals to prevent a galvanic acshould be avoided to prevent corrosive tion. Extra precaution s would ina ction between the receiving surface clude: and the aluminum. Masonry surfaces(lime, motar, concrete, plaster, etc.)
(a) 	Painting the dissimilar metal with must be coated with alkaline-resistanta prime coat of zinc chromate or coatings such as heavy bodied bituother suitable primer, followed by minous paint or water-white metha
one 	or two coats of aluminum or crylate lacquer. Wood can be treatedother type paint. Paints containing with bituminous paint, or two coatslead pigmentation shouid not be of either aluminum house paint, pentaused for the priming coat. 
chlorophenol ( 5 ?C mm1mum concen
(b) 	Painting the dissimilar metal with tration) , Wolman salts, creosote, ora heavy coating of bituminous paint. 
zinc naphthenate. Wood may also be
( c ) 	Caulking material placed between 
covered with waterproofing buildingthe two metals. paper.
(d) 	Nonabsorptive tape or gaskets used 
(2) 	F as t en ers, seam s, and j oints. Only
as 	insulation between the two aluminum fasteners should be used tometals. 
secure aluminum sheets because of its
(4) Reflectivity. Aluminum has an exhigh affinity for galvanic action. Alceptionally high heat and light reflecthough aluminum is ductile enough totivity. The heat reflectivity is between permit the use of most seams, the85 and 98 percent depending on the Pittsburgh or hobo seam (par. 30cL)brightness of the surface. Aluminum is most commonly used. Soldering,
is used to reflect heat from roofs, alt hough possible, is not recommended.ducts, heaters, and radiators. SpeIn thickness less than .040 inch, mecially prepared surfaces will reflect chanical fastenings should be used,light up to 95 percent and are utilized and for greater thickness, aluminumas reflectors for interior and exterior is usually welded using a shield oflighting. inert gas (par. 28).
(5) 	Conductivity. Aluminum is an excel(3) Pr otective coatings. Three types oflent conductor of heat and electricity. protective coatings are applied by proHeat transfer systems and cooking ducers of aluminum to protect the sur
vessels are made of aluminum because 	face during storage, !ransporting and 
16 
AGO 8488A 
construction. Coatings of cleam an d 30 7c nickel ) has similar characteristics and methacrylate lacquer protect against uses of monel but does not have the high cor
The three
atmospheric and chemical corrosion rosion-resistant qualities of monel. offer little protection against abratypes of monel commonly used are B, K, and R. sion. Lacquer coatings eventually B-monel is the most common of the three and vanish from the effects of weather and has excellent resistance to corrosion and retains need not be removed unless other coatits physical properties at high temperatures. ings are to be applied. Sprayed stripK-monel contains 2-4 percent aluminum added pable coatings are generally applied to the alloy and possesses greater strength and to small area surfaces with decorative resistance to salt water. K-monel is used in finishes. Exposure to high heat or salt water areas and marine applications. Rstrong sunlight for long periods will monel has 1.5 percent sulphur added to give dry out these coatings and hamper free machining properties and is generally their removal. Tapes and adhesive used for hardware and solid shapes rather than paper are used on small area sursheets. faces with extremely fine finishes. a. T empe1·s. Monel is annealed by heat treatThese coatings should not be removed ment and is supplied in various degrees of until the items are installed and all hardness. The hardness of monel is greater surrounding construction work is finthan mild steel and is increased by cold workished. Protective coatings applied ing. after installation include lacquer, wax, b. Thickness. The thickness of monel sheets and paints. Clear methacrylate lacis measured by the Brown and Sharpe (Ameriquer coated with wax will protect excan standard for nonferrous wire and sheet posed aluminum for several years. metal) gage numbers (par. llb), and by thickWax alone offers temporary protection ness in inches. Purchases are made on the and requires periodic cleaning and rebasis of the latter system. waxing. Painting and applying proc. Charact eristics. tective coatings to aluminum, if re(1) Durability. Monel is a n extremely quired, should be done in accordance durable metal, but its cost usually dicwith Military Specification MIL-T-tates special applications for use 704C and TM 5-618. around sea water or in laboratories 
e. Maintenance. Aluminum should require for resistance to acids . little or no maintenance except cleaning of dec(2) Workability. Monel is a tough, stron g orative finishes and routine maintenance inmetal and is more difficult to work spections to check for physical damage, evithan mild steel. However, monei is dence of corrosion, and damage from expansion ductile and can withstand most formand contraction (aluminum has a high coeffiing and bending operations without cient of expansion). fractures. Machinery should never be taxed to its capacity when cutting or
f. Reuse of Aluminum. Aluminum that has been cold worked is seldom suitable for reuse. forming monel. The t h ickness of monel sheets should not exceed %. the
Pref ormed aluminum items are seldom dam
agedged through use and can usually be rethickness of mild steel sheets for the 
stored to original finish and economically rated capacity of machines. 
reused. d. I nstallation. 

(1 ) Surface preparation. Surfaces to re
14. 	Nickel Copper Alloy (Monel) ceive monel should be treated the same Monel (Fed. Spec. QQ-N-281) is a nickelas for copper (par. 12d) . copper alloy made up of approximately 65 per(2) Fasteners, seams and joints. Monel cent nickel and 30 percent copper. Small fasteners should be used to secure quantities of a luminum, chromium, iron, manmonel sheets. For roofing and sidi n g ganese and sulphur made up the other 5 percent a standing seam is usua lly recomof the alloy. Copper-nickle alloy (70 7c copper mended. Monel is easily soldered b ut 
AGO 8488A 	17 
lacks strength. Resistance or arc welding is recommended for joints. The high melting temperature of monel renders it impractical for cutting or welding with a gas torch. 
(3) 	P1·otective coatings. Monel is generally used because of its durability and decorative qualities and, therefore, is seldom given any protective coating. Clear Methacrylate lacquer and wax are sometimes used to retard tarnishing. Painting if desired should be done according to the instructions for copper (par. 12d(3)) and TM 5-618. 
e. 
Maintenanc e. Monel tarnishes rapidly and requires frequent cleaning. Routine maintenance inspections should be made twice a year or more frequently if conditions are severe. 

f. 
Reuse of Monel. Monel is one of the most expensive sheet metals and should be used only where essential. Its resue is highly recommended when possible. 


15. 	Brass 

Brass (Fed. Spec. QQ-B-613) is an alloy of copper and zinc containing 65-90 percent copper and 10-35 percent zinc. Sheet brass contains 85-90 e~·cent copper and 10-15 percent zinc. Brass is used where materials harder than copper are required and for ornamental purposes. Brass strips are used where strength and corrosion resistance are required. 
a. 
Tempe1·. Various degrees of temper are avaliable and are specificed by fractions of hardness. One-quarter-hand is slightly harder than wrought copper. Half-hard brass is equal to low carbon steel. Hard bra1:s is equal to medium carbon steel with a mild temper. Full hard and spring usually exceed the strength of structural steels. 

b. 
Thickness . The thickness of brass sheets is measured in decimal fractions of an inch and more commonly by the Brown and Sharpe Gage System (par. llb). 


c. CharacteTistics. 

(1) Dumbility. Brass offers good resistance to industrial, rural, and marine atmospheres and some resistance to weak acids. However, brass has poor resistance to ammonia, ferric and ammonium compounds, and cyanides. Special sheet brasses containing more than 20 percent zinc have a tendency to dezincify or break down leaving free copper in the metal causing a galvanic action between the copper and brass. Dezincification is caused by
(a) 	
Moderate concentration of certain acids or salts, especially chlorides. 

(b) 	
Limited amounts of dissolved oxygen. 

(c) 	
Low velocity water flow of stagnation . 

(d) 	
Elevated temperatures (above 600 ° 


F.). 
(2) Workability. Sheet brass, except when annealed, has a distinct grain running the length of the sheet. Fractures will result if sharp bends 90° or more are attempted in the direction of the grain. All bends and folds in brass should have a slight radius rather than a sharp corner to prevent fracture and future metal fatigue. 

d. Installation. 
(
1) 	SuTface preparation. Follow the same procedures outlined for copper (par. 12d(1)). 

(2) 	
Fast eners, sec~ms and joints. Brass fasteners should be used to seam all brass sheets and fittings. Seams should be limited to as few folds as possible. Refolding should never be attempted as fracture will occur. Brass is excellent for lead-tin soldering and silver alloy brazing. Arc welding is possible but not recommended. 

(3) 	
PTotective cocLtings. Normally, the natural finishes of brass whether caused by exposure or artificial means provides adequate protection. When painting is desired, brass can be treated the same as copper. The following finishes are produced for ornamental effects or ease of cleaning. 


(cL) 	B1·ight finishes. Bright finishes are recommended on surfaces that are continuously handled (doors, pushplates, handles, etc.) and should be free of protective coatings to per-
AGO 8488A 


mit frequent polishing. Bright surfaces that are not handled may be coated with wax or clear methacrylate lacquer to eliminate the necessity of ferquent polishing. The brass surface must be free of all dirt, grease, and fingerprints, and finished with fine steel wool or abrasive cloth before aplying lacquer. 
(b) 	Da1·k finishes . An antique or dark finish can be created artifically by brushing on several applications of potassium sulfide solution (liver of sulfer) until the surface is darker than required. The finish is then relieved or lightened by gentle rubbing with fine steel wool or powdered pumice. The final finish is set with a coating of lemon oil, followed by vigorous rubbing with a soft cloth. 
e. Mctintenance. Unprotected bright surfaces require frequent polish ing. Dark finishes should be cleaned with detergent and water ; polish and abrasives will cut through dark finishes. Lacquered surfaces must be stripped to the bare metal and refinished before relacquering. Brass used for structural purposes should be included in routine maintenance inspections. 
f . R euse of Bmss. Decorative brass can generally be reused with little difficulty except cleaning or restoring the finish. Brass that has been distorted or exposed for long periods must be inspected carefully for fractures and hairline crack s r esulting from excessive stress or age hardening. 
16. 	Lead 

The use of sheet lead (Fed. Spec. QQ-L-201) in construction is limited to specific applications centered around extremely high corrosive resistance, gamma or x-ray shielding or sound and vibration deadening. Lead has little strength and is often used as the coatings on cladmetals (par. 22d) which utilizes iron or copper as the supporting sheet and lead as the surface protection. Plain lead sheets are usually useless for structural purposes because lead has a tend ency to creep and become lifeless or dead with age as shown in figure 9. 
Figm·e 9. Effect of age on lead. 

a. 
T empeT. Lead is an extr emely soft metal and in sheet form is usually free of hardeners and cannot be tempered or work-hardened. In special cases, small quantities of antimony, arsenic, copper, zinc and metallic sulfides are alloyed with lead to increase the hardness. 

b. 
Thickness. The thickness of lead sheets is measured in pounds per square foot. A pound of lead rolled out to one square foot is approximately l;(H of an inch thick. Table 5 lists the mor e common weights of lead with their decimal and fraction of an inch equivalent. 


c. Characteristics. 
(1) 	
Dumbility. Lead is durable with respect to corrosion resistance but is readily subject to failure when subjected to erosion or stress. Lead is us ed as a protective lining for manufacturing and storing many chemicals because of its durability and resistance. Most chlorides, some fatty and organic acids, and cinders have a slight corrosive effect on lead. 

(2) 	
Workability. Lead is highly ductile and conforms easily to any shape. Lead is also plastic and should be formed slowly to prevent internal stresses from building up. Rapid working of lead often leads to fractures and metal fatigue. 

(3) 	
To xicity. Lead is toxic and must not be used to handle food. Hands should be washed after handling lead and wounds treated immediately to prevent infections and lead poisioning. 


AGO 8488A 


Table 5. Thickness of L ead Sheets 
Average thi c.tt ness in inches 
Pounds per square foot  
Decimal  Fraction  
aA----------------------- 0.0117  IA!u  
1------------------------ 0.0156  lf<H  
1 ~----------------------2 _________ __ ______________  0.0234 0.0312  ~bs 'l32  
21h----------------------3__ _______________________  0.0391 0.0468  o/t~s  
3~----------------------4 ________________________ _ 5 __________ _______________ 6________________________ _  0.0547 0.0625 0.0781 0.0937  
8------------------------10________________________ 12 ___________________ ____ _ 14 _______________________ _ 16________________________ 20________________________ 24________________________ 30________________________ 40________________________ 60________________________  0.1250 0.1563 0.1875 0.2188 0.2500 0.3333 0.4000 0.5000 0.6667 1.0000  

d. Installation. 
(
1) Surface prepctration. Surfaces receiving lead must be smooth and free of all foreign matter. 

(2) 	
Fasteners, seams, and joints. All fasteners should be coated with lead. Seams in lead lack strength and must be soldered or reinforced. Soldered joints are not as corrosion resistant as pure lead. Where joints are subject to corrosive action from water and chemical lead "burning" is r ecommended. Lead "burning" utilizes a hydrogen torch to heat the lead being joined and a lead filler rod to their melting point. The joint is sealed by the filler rod. This process is similar to brazing (par. 27) and should not be attempted by inexperienced personnel. 


Caution: The fumes generated by lead burning are extremely toxic. Personnel subjected to lead fumes must be protected by approved breathing apparatus (cannister masks) to prevent lead poisoning. 
(3) 	Protective coatings. Lead is seldom given a protective coating because the lead combines chemically with corrosive elements to form a protective film that arrests further corrosion. For instance, sulfuric acids combine with lead to form lead sulfide, phosphoric acids form a coating of lead phosphate, and chromic acid forms lead chromate. These coatings vary from a light tarnish to a heavy coat. Variations in temperature, concentrtion of solution, and stress have a tendency to break 
down or rupture these coatings, but lead has a self-sealing characteristic that restores the coating to the affected area. When painting is desired, any lead base paint can be used as primer and finish coat. 
e. 
Maintenance. Lead should be cleanec1 with soap and water to remove dirt and foreign matter. The protective films should not be removed. Maintenance inspections should be made to check for loose seams, enlarged holes around fasteners, sagging sheets (lead is plastic and has a tendency to creep), evidence of corrosion in corners and joints and excessive wear. 

f. 
R euse of L ead. Lead is usually shaped or formed for a specific use. Therefore, reclaimed lead is seldom in flat sheets or rolls. The condition of the lead, storage space required, and the possibility of future use must be considered before deciding to store reclaimed lead. Lead that has had laboratory or chemical applications must be cleaned thoroughly to remove the toxic protective coatings formed on the surface of the lead. 


17. 	Galvanized Iron and Steel 
Galvanized iron and steel (Fed. Spec. QQ-S775) are sheets of black iron or mild steel with a zinc coating to produce an inexpensive sheet metal of high strength and corrosion resistance. The zinc coating also provides a shield agaim:t electrolysis. As long as iron is in the presence of zinc, any galvanic action will be with the zinc instead of the iron. The factors influencing t he use of galvanized iron are high strength, corrosion resistance, low coefficient of expansion, good workability, and low initial cost. Uses of galvanized iron include roofing and siding (usually corrugated), ductwork, gutters, downspouts, and flashings. 
AGO 8488A 
a. Temper. The steel sheets are a low carbon (2) Fasten ers , seams and foints. All steel and provide the maximum strength withfasteners must be galvanized (lead or zinc coated). Seams are generally
out sacrificing ductility. Any attempt to in
crease the temper by heating and quenching used for ductwork and prefabricated will destroy the zinc coating. Excessive cold items; the most common used with working will crack the zinc surface. galvanized iron is the Pittsburgh seam (par. 30a). For roofing and siding
b. Thickness. Galvanized iron is not measthe sheets are usually corrugated andured in thickness as such, but rather by the use an overlapping seam. Where tightgage (U.S. Standard for Iron and Steel Plate) 
of the steel sheet and the quantity (oz per sq 	connections are required, joints are usually soldered and the zinc coating
ft) of zinc coating. For most structural purserves as pretinning. Welding andposes the steel sheets range from 10 to 30 gage; brazing destroy the zinc coating and26 gage being the most common. The two most are not recommended.
common weights of zinc coatings are 1.25 ounces for general construction work and 2.0 (3) Protective coatings. Paint is the only 
protective coating recommended for
ounces for severe atmospheric conditions or high corrosive resistance. galvanized iron and is done for three 
reasons: appearance when the zinc
c. Characteristics. 
surface does not fit in with the decora( 1) Durability. Galvanized iron is not 
tive or color scheme, h.eat reflectionconsidered to be a permanent metal. 
(white paint only) to reduce the heatExposed to the elements, galvanized 
transferred through the roof and
iron offers 15 to 60 years of service 
walls, and extended life to preventdepending upon the severity of condidamage of the iron sheet after the zinctions. In applications where strength coating is damaged. New galvanized and flexibility are important, galvaniron, unless specially treated is not ized iron will usually outlast most receptive to paint. "Galvannealed" other materials. and "phosphatized" are two common 
(2) 	Workability. Galvanized iron resists factory treatments which render galvanized surfaces receptive to paint.
bending and folding more than other metals but is still soft enough to be The galvanized surface should be cleaned with soap or detergent and
worked without the aid of special mawater, and wiped with turpentine,chinery. All types of folds and bends mineral spirits, or naphtha. After
can be made without fracturing the 
cleaning apply a wash primer (MILiron sheets or zinc coating. Repeated C-14504) to provide proper adhesionworking will eventually break down of paint and then apply zinc-dust-zincthe zinc coating and should be avoided. 
oxide (Fed. Spec. TT-P-641) paint or
d. Installation. 	other paints being used on adjacent
(1) Su'rface preparation. Galvanized iron, wood or metal surfaces (TM 5-618).utilized for roofing and siding pure. Maintenance. Painted galvanized surposes, is seldom applied to a solid surfaces generally require repainting every 5 toface but rather to frame work and 7 years. Unpainted surfaces must be inspaced slats. The frame work should spected for condition of the zinc coating and be aligned to permit even nailing and fasteners. Loose or missing fasteners must be provide a level surface. If the surtightened or replaced immediately to prevent face to which the galvanized iron is excessive strain on the remaining fasteners. to be applied is other than wood, lead Damaged or unprotected surfaces should be strips or other insulating material painted to prevent corrosion of the exposed (par. lle ) should be applied to the steel sheet. frame before installing the galvanized f. R euse. The initial cost of galvanized iron iron. is low, and exposed surfaces have usually de-
AGO 8488A 	21 
teriorated. Galvanized iron sho ld not be rewet wood, and masonry. Heavy bodiedclaimed except for temporary se when the bituminous paints or building papersurfaces are in good condition. sh ould be used to insulate the zinc.The surface must be smooth and free
18. Zinc 
of high spots that will cause wear orThe development of new metals and alloys indentations in the zinc.has gradually eliminated the use of sheet zinc 
(2) Fast en ers, seams, and joints. All
(Fed. Spec. QQ-Z-00100). However, in recent 
fasteners must be zinc or galvanized
years alloys of zinc, titanium and copper, 
metal. Seams are difficult to form
with traces of manganese and chromium have 
and will split in cold weather because
produced sheet metal of many desirable qual
zinc is nonductile. Soldering is the
ities not associated with sheet z:nc described 
preferred method of securing seams
below. This material is more economical than 
and joints. Welding or burning breaks
copper and for many uses will serve the pur
down metallic zinc to zinc oxides. Me
pose equ a lly as well. Zinc has similar proper
chanical fasteners and solder are the
ties and characteristics as lead but is nontoxic 
only practical methods of securing
and has a higher melting point and, for these 
zinc.
reasons, is sometimes used in lieu of leads. 
( 3) Protective coating. The applications
Uses of sheet zinc include roofing, flashings, 
of zinc are usually such that they do
sinks, drainboards, table tops, wall liners, food 
not warrant protective coatings. How
containers, and cold storage walls. 
ever, when painting is desired, it
a. T empe1·. Sheet zinc is hardened through 
should be accomplished as set forth
the addition of alloys and is avai'able in dead 
in TM 5-618.
soft, soft, hard-soft, and hard temper. All 
e. Maintenanc e. Zinc is soft and plastic
grades are relatively soft compar ed to other 
which makes it subject to "creep" when under
metals except lead. 
continuous stress. This characteristic causes
b. Thickness . Zinc has a gage number clas
sheets to sag, breaking seams and loosening
sification of its own. Each increase in gage fasteners. Maintenance inspections should innumber is equal to 0.002 inch. Common thick
clude checks of all seams, joints, and fasteners,ness used are 20 gage (0.032 i .) , 24 gage especially in large sheets.
( 0.024 in.) and 26 gage (0.020 in.). 
f. Reus e of Zinc. Reclaimed zinc has prac
c. Chamcte1·istics. tically no value either for reuse or scrap.
(1) Durability. Zinc is highly corrosive 
19. Terne Plate
resistant in the presence of salts andweak acids. However, it is readily Terne Plate (Fed. Spec. 00-T-201) is sheet attacked by strong acids. High temsteel with a lead-tin alloy coating. The leadperatures (near the melting point, tin coating provides a surface that is highly 792 ° F.), extremely low t emperatures receptive to paint and extends the intervals beand cold working have a tendency to tween paintings. Minute perforations in the break down the zinc and cause metal lead-tin alloy permit corrosive elements to atfatigue. tack the steel sheet; thus, painting is required.Terne plate is also toxic because of its lead-tin
(2) Workabi lity. Zinc, although soft and 
coating and cannot be used where food is han
plastic, is nonductile. Bends and folds 
dled. (Tin plate, which is steel having a pure
must be made slowly an preferably 
tin coating is not toxic and may be used in con
at temperatures of 100-150° C. (212
nection with food handling). Application of
3020 F.). Rapid workino will frac
terne plate include roofing, siding, flashings,
ture zinc. 
and copings.
d. Installation. 
a. Tempe1·. The temper of terne plate is de
(1) Surface preparation. Zinc is highly pendent upon the mild steel sheet under theactive in galvanic actions and must coating and is copper bearing steel of low carnot come in contact with other metals, bon content similar to galvanized iron. 
22 AGO 8488A 
b. Thickness. Thickness of terne plate is 20. Corrosion-Resisting {Stainless) Steel 
measured in the gage of the basic sheet (usually Corrosion-resisting steels (Fed. Spec. QQ-S24-to 30-gage) and the weight of the lead-tin 766, QQ-S-682) are alloys of steels with varycoating in ounces per square foot (or lb per ing compositions of chromium, nickel, and copdouble base box-8; 20; or 40) . per. Most of the structural stainless steels are 
c. 	Chamcte1·istics. of a chrome-nickel-steel alloy and are austenitic in nature which means they cannot be heat
(1) 	Durability. Unpainted terne plate will rust because of the minute perforatreated but must be cold worked to alter their tions in the lead-tin coating. Unlike physical characteristics. Chromium stainless steels contain no nickel and are martensitic
galvanized iron, the lead-tin coating (less than 18 percent chrome) or ferritic (18
offers no protection against galvanic action after the steel sheet is exposed. 30 percent chrome) in nature. Their physical Painted terne plate, (TM 5-618) if characteristics can be changed with heat treatkept painted should outlast galvanized ment. AISI (American Iron and Steel Institute) numbers are generally used to differenti
iron. 
ate 	between the stainless steels, but in many
(2) 	Workability. The workability of terne 
cases the SAE (Society of Automotive Engiplate is the same for mild steel or galneers) numbers or composition ratios are used.
vanized iron. 
The first number of the composition ratio indi
d. lnstallcdion. 	cates the percentage of chrome and the second 
(1) 	Surface p1·eparation. The unexposed number indicates the percentage of nickel al
side of terne plate should be coated loyed with steel.
with paint (Fed. Spec. TT-P-31) be

a. Types of Corrosion-Resisting Steels.
fore installation. Exposed surfaces should be painted as required, after (1) AISI 301 (SAE 30301 or 17-7 compobeing given one prime coat of lead and sition) is a good general purpose oil paint. Masonry surfaces or surstainless steel used primarily in strip faces that are subject to repeated form for roof drainage applications. This steel has very high work harden
dampness should be coated with heavy bodied bituminous paint. ing properties and is difficult to form and fabricate.
(2) 	Fasten ers, seams and joints. Lead coated fasteners should be used with (2) AISI 302 (SAE 30302 or 18-8 compoterne plate. The lead-tin coating will sition) is the most widely used of the withstand severe folding and bending stainless steels. It will resist most before breaking down and can be utilcorrosive elements and has excellent ized in all forming and bending operaworking qualities for structural and tions. Soldering is recommended for architectural purposes. It is used exall seaming and joining operations. tensively in kitchens and food prepaThe lead-tin coating eliminates the ration areas. necessity of pretinning. Brazing and (3) AISI 309 (SAE 30309 or 25-12 comwelding destroy the coating in the position) has better corrosion resisarea of the weld and are not recomtance than AISI 302 and will resist mended. scaling at temperatures up to 2,000° 
e. Mc~intenance. Unde11 normal conditions F. This steel is primarily used for terne plate will require little or no maintenance high temperature work. except painting at periodic intervals. Mainte(4) AISI 31 6 (SAE 30316 or 18-8 MO nance inspections should include a visual incomposition) has the same composispection for evidence of rust and corrosion intion as AISI 302 except that 2-3 perdicating the need for repainting. cent molybdenum has been added to 
f. Reuse of Terne Plate. The low initial cost increase high temperature strength of terne plate makes it impractical and unand corrosion resistance. AISI 316 is economical to store or salvage. considered to be the premium of the 
AGO 8488A 
.______ _ 
stainless steels and is used for marine generally specified for articles that areapplications, sea coas: construction to be polished after severe forming.and in areas where corrosive indus
(3) 	No. 2B finish. Light cold rollingtrial fumes contaminate the atmosafter final annealing and pickling prosphere. 
duces a bright dense surface of harder
(5) 	AISI 410 (SAE 51410 or 12 . (12 % temper than No. 2D finish. The 2Bchrome, oro nickel) composition) is finish is specified where immediate anthe general purpose mar tensitic stainnealing and pickling are not requiredless steel. It is used where high as for shallow pans, serving trays,strength and low corrosion resistance and decorative stampings.is required. 
( 4) 	No. 4 finish. The surface is ground
(6) 	AISI 430 (SAE 51430 or 17 (17 7'o with successively finer abrasives tochrome, 07c nickel) c mposition) is remove all imperfections and producethe most widely used of the ferritic a uniform bright surface with a goodstainless steels. It has good corrosion 
luster. No. 4 finish is supplied whereresistance but less strength than AISI "commercial" or "standard" finish is
410. AISI 430 cannot be hardened by specified and is used in forming operaheat treatment or cold working and is tions where the original finish will not
ductile enough to be roll formed. Most be destroyed or otherwise require
applications of this steel are for inrefinishing.
terior use. 

(5) 	No. 6 finish. Commonly called "tam
b. Temper. Because of the variety of stainpico brushed" is produced on No. 4less steels and the different degrees of hardness finish by using a rotary brush of tamdeveloped through heat treatments and cold pico fiber charged with fine abrasives.working, a set of standards cannot be given for No. 6 is a conservative, soft, satinthe hardness of stainless steal. Generally, the finish with low reflectivity and is usedaustenite stainless steels range from 135 to 185 where glare or brilliant reflectionsBrinell (B75-90 Rockwell) in annealed condiare undesirable as in architecturaltion to 175-627 Brinell (C5 to 58 Rockwell) work to produce a contrasting effectwhen cold worked. Martensitic and ferrite with a higher finish.stainless steels range from 130 to 185 Brinell 
(6) No. 7 finish. A highly polished, semi( B70 to 90 Rockwell) in an annealed condition mirror finish produced by buffing No.to 180-375 Brinell (C10 to 41 Rockwell) after 
4 finish with high speed buffers and
heat treatment and working. 
fine abrasives. No. 7 finish is used
c. Thickness . The thickness of stainless steel as a higher contrast to the other finsheet is usually determined by a gage number ishes and for decorative rather than
(U.S. Standard for Iron and Steel Plate, (par. structural uses.llb). Decimal fractions of an inch are also 
e. ChaTacte1·istics.
used but are less common. 
(1) 	Durability. Corrosion-resisting steelsd. Types of Finish. Stainless steel sheets are will resist the action of most corroavailable with several surface finishes. 
Each sive agents including salts and acids.
finish is suited to a particular ty e of job. 
Muratic acid and chemicals contain
(1) 	No. 1 finish. Hot rolled, annealed and ing chlorides and fluorides have a cor
pickled to give a smooth, soft and pure rosive effect on stainless steels.surface for technical and chemical ap
(2) 	Wo1·kab i lity. Most of the stainlessplications. No. 1 finish is seldom used steels can be worked with little dif
for 	structural purposes. 
ficulty. However, continuous working
(2) 	No. 2D finish. Cold rolled before final will harden the metal and cause metalannealing and pickling to produce a fatigue. For excessive working orcompact dense surface an sheets with forming, the possibility of specialmaximum ductility. No. 2D finish is stainless steels should be considered. 
24 	AGO 8488A 
When cutting stainless steels, the cutof the stainless steel to eliminate the ter edges must be kept sharp and set possibility of damage during or after at a close tolerance to prevent the installation of the surrounding work. stainless steels from drawing be(2) Fasteners, seams, and joints.tween the cutters, leaving a ragged (a) Fasten ers. All fasteners used must
edge. Cutting and punching operabe of corrosion-resisting steel.
tions require twice the power normally 
Ordinary iron or steel fasteners correquired for ordinary mild steels. rode and leave rust deposits on theDrilling and sawing operations also 
surface of stainless steels. For inrequire special attention. Center
stallations in kitchens or where foodpunching should be done lightly to is to be handled, mechanical fastenprevent work hardening. Drills should ers are usually undesirable because
be of the high speed type with a flat dirt and bacteria lodge behind suchground cutting edge. Low-speed, highfasteners creating a health hazard.
pressure equipment is required to keep Adhesives, welding and hidden fast
a cutting action at all times. If drills eners on the backs of the sheets areand saws are permitteci to move on the 
recommended in these cases.
surface of stainless steel, the area will 
(b) 	Seams . Stainless steel is ductilebecome work hardened and prevent enough to permit all of the seamsfurther cutting. For deep holes and applicable to sheet · metal work.
cuts, a mixture containing 1 pound of Soldering procedures are the samesulfer and 1 gallon of lard may be as for ordinary iron and steel.
used as a cutting compound. The thickness of stainless steel sheets used (c) Joints. Strength is often an imin folding and forming machines portant factor for stainless steel inshould be 2 gages less than the rated stallations, and welding is usually capacity for mild steel sheets. recommended. Acetylene welding is used on lighter gages (under 0.050
(3) 	Miscellaneous. Other characteristics 
in.) 	with the use of jigs, forms, andthat differentiate stainless steel from chill bars (see glossary) to preventordinary steels are coefficient of exthe heat and stress from spreadingpansion and resistance to electrolysis. 
away from the area of the weldThe coefficient of expansion range for causing the rest of the sheet tostructural stainless steels is 0.0000058 
buckle. Electric arc welding, both(for AISI 430) to 0.0000096 (for AISI as spot or continuous weld, is the302). Generally the expansion and most common method of joiningcontraction for stainless steels is 50 heavier gages (over 0.050 in.).
percent greater than carbon steels. 
Direct current instead of alternatStainless steels are subject to corroing current is used with the weldsion from galvanic actions, but the ing rod being positive and the workdamage is only about one-third that of negative. Welding rods must be ofordinary iron or steel subjected to the higher alloy content that the worksame conditions. 
to allow for dilution and oxidation
f. Installation. 	of the weld metal. Special fluxes 
(1) 	Surface preparation. In most cases are necessary and many are availstainless steel is used as a trim or final able in commercial forms with the outside covering and is therefore one particular manufacturer's instrucof the last components installed. The tions for use. When possible the surfaces should be completely ready to inert gas shield method of arc weldreceive the stainless steel, and all coning should be employed. An inert struction work in the area should be gas shield produces a clean, nonfinished before attempting installation porous weld with a rod of the same 
AGO 84 88A 	25 
material as the base metals and eliminates fumes, spatters, residue, and the need for flux. Atomic hydrogen welding has proven successful on thickness up to 0.109 in. and produces a smooth, nonporous weld. 
(3) 	Prot ectiv e coatings. Quite often temporary protective coatings are applied by manufacturers to protect their products during shipping, storage, and installation. These coatings are in the form of strippable plastic coatings, tapes, and adhesive papers. Age and exposure to heat and sunlight tend to dry out these coatings, making them difficult to remove. Periodic checks must be made to make sure these coatings do not dry out. When evidence of drying out is noticed the coatings must be removed before the use of scrapers or similar too s are necessary. Protective coatings after installation are not necessary and are seldom used. Painting is done for decorative reasons only and can be accomplished by roughening the surface with stainless steel wool, abrasives (iron free), or chemical etching solutions such as phosphoric acid treatments. A variety of paints is used on stainless steel and the use and method of application are recommended by the manufacturer. 
g. Maint enance. Other than routine maintenance inspections, the only periodic maintenance required with stainless steel is cleaning. Normal cleaning is accomplished with mild detergent and water. Heavy accumulations of dirt containing oil or grease will require solvents. Organic solvents are usually satisfactory and will not harm the finish. Other deposits or stains require the use of stainless steel wool or abrasives. Use only stainless steel wool and scraper. Ordinary steel wool and scraners will contaminate the surface and eventually leave rust stains. Recommended abrasives include fine grade whiting or pumice, stainless steel cleaners, fine grade commercial scouring powders, and abrasive metal cleaners. Abrasives must be applied with a soft, damp cloth and rubbed lightly to prevent scratching of highly 
polished surfaces or bright spots in a dull surface. 
h. R euse of Stainless Steel. Stainless steels are considered permanent metals and have a high initial cost. Reuse is practical and economical with respect to flat sheets and fabricated items with potential use. Because of the rapid work hardening properties of stainless steel, pieces that have been severly stressed or formed can seldom be reused and should be scrapped. 
21. 	Black Iron 
Black iron, (Fed. Spec. QQ-S-636) commonly called "hot rolled, black sheet steel", is a low or mild carbon steel and the least expensive of the sheet metals. Unprotected, black iron offers little resistance to corrosion but high resistance to erosion and abrasion. Often, black iron is the base sheet for clad or coated metals such as galvanized iron (par. 17) and terne plate (par. 19). Most of the uses of black iron are centered around the low expense, high strength, and abrasive resistance. For these reasons it is used where the metal is expected to be worn away or consumed during use as in treadways, stove pipes, and floor plates around machinery. 
a. 
Temper. Black iron sheets are usually furnished in an annealed condition. The uses of black iron rarely require hardening, but when necessary, it can be work hardened or tempered by heating and quenching. 

b. 
Thickness. Black iron sheets are generally referred to by gage number (U. S. Standard for iron and st eel plate). However, black iron plates are referred to in fractions of an inch. 


c. Charac t eristics. 
(
1) Durab1:lity. Black iron is readily attacked by atmosphere, moisture, oxidizing agents, and acids. The durability of black iron is based around its resistance to heat and abrasion where it will usually outlast most other metals. 

(2) 	
Workability. Black iron is ductile and can easily be formed and worked. For severe forming operations, the iron is usually heated to its annealing temperature to prevent fracture. 


AGO 8488A 
d. Installation. 
(
1) 	Surface preparation. No special surface preparations are necessary. 

(2) 	
Fasteners, seams, and joints. Iron or steel fasteners should be used. Black iron is ductile and permits the use of all seams and forming operations. Soldering, brazing and welding are all acceptable methods of joining iron. 

(
3) 	Protectiv e coatings. Iron is usually painted to offer some protection against corrosive elements. Two coats of prime red-lead paint followed by a finish coat of lead base paint, except for high temperatures, produces the most satisfactory result (TM 5-618). 


e. 
Maintenance . In general, repair of black iron is limited to the replacement of a sheet or portion of a sheet. If the affected area is small in comparison to the size of the sheet, a patch can be welded in the damaged section. If the damage covers a large portion of the sheet, replacements is necessary. 

f. 
R euse of Black Iron. The low initial cost and severe abuse inflicted during use usually render it impractical to utilize reclaimed black iron. 


22. 	Miscellaneous Materials 
Many new materials constantly are being developed to provide better and, in some cases, less expensive materials for structural purposes. In some cases these materials are new alloys of the present metals and in other cases nonmetalic materials are being developed to replace sheet metals. 
a. Alloys. Most of the alloys have a small percentage of other materials added to a base metal to improve one or more characteristics of the base metal, thus making it more suitable for a specific job. These metals usually retain the characteristics of the base metal and can be treated in a similar manner. Other alloys are compr ised of large percentages of different metals and materials and often lose the characteristic of the base metals. These metals usually require special treatment and their manufacturer should be consulted for the specific details in handling their product. 
b. Plastics. The use of plastics in structural work is increasing but is still limited. Plastics are considered temporary and their use should be restricted to interior use or in places where replacement can be accomplished with little dif
ficulty. Most plastics used in structural work are preformed (shingles, flashings, trim, etc.) and can be installed in a manner similar to sheet metal. However, the field of plastics is large and complicated and other operations such as forming and fusing should be restricted to personnel specifically trained in this field. Plastic sheets of polyethylene, polyester, vinyl, and such are available in various thicknesses and sizes. 
c. 
Asbestos-Cement Materials. Asbestoscement sheets, consisting of portland cement and asbestos fiber formed into a dense, hard, tough, homogeneous material, are frequently used for ductwork, wall linings, heat insulators, roofing, and siding instead of sheet metal. Substitute pipe material such as asbestos-cement, vermiculate-cement, and terra cotta, are being used for smoke stacks, vents, sleeves, and drains. These materials vary in thickness from three-sixteenths of an inch to over 2 inches. 

d. 
Clad M etals. Clad metals are two metals bonded together to produce a metal that has qualities superi or to those of one metal alone. 


Metals are clad to increase corrosion resistance, produce a surface more receptive to paint, or to produce a decorative effect. Iron is clad with with zinc (galvanized iron) to increase the corr osion resistance but still have the strength of the iron sheet. Copper is often clad with lead to prevent the copper from staining nearby surfaces and t o make the copper more receptive to paint, and at the same time have a base metal with the durability of copper. Folding and forming operations for clad metals is the same as for the base sheet except excessive working has a tendency to crack the less ductile metal or separate the two metals. Inst allation must take into consideration the possibility of galvanic action between the two metals or between a third metal and the more active of the two clad 
metals. 
e. Protected Metal. Protected metals are thin layers of metal such as iron, copper, aluminum and such, sandwiched between two layers of protective material like asphalt, felt, and plas-
AGO 8488A 

tics. (TM 5-617) This material has its widest usage in corrugated siding and roofing; and, as flashings of various type. Wartime roofing of 5-ounce copper so protected are still in service at extreme northern locations after 20 years. Therefore, this is a good method of conserving critical metals during periods of national emergencies. Protected metals should be installed, repaired, and maintained as recommended by the manufacturer. 
23. Mastics and Calking Compounds 
Mastic and calking compounds are available in a variety of forms for many jobs. Available forms are tapes, putties, pastes, paints, and solutions. Primary uses include bonding, calking, sealing, and insulating. 
a. 
Tapes. Tapes or ribbon sealers are applied to the overlapping edges of sheet metal before joining them with mechanical fasteners or after the final seaming operations to provide airtight and watertight joints. Tapes are generally used along the seams and around the joints of ductwork. 

b. 
M etal fillers. Putty and paste forms are used to fill cracks, tears, and dents in metal surfaces. Calking compounds usually fall into this group. White lead (Fed. Spec. TT-W-261) is a common compound used to fill seams in roofing when soldering is undesirable or impractical. Plastic calking compounds (Fed. Spec. TT-C-598 or TT-S-00227 (GSA-FSS)) are used in masonry joints and at joints formed between masonry and metal or wood. The latter being a rubber-base material, it will remain in a plastic state much longer than the former. When filling roofing seams, use only enough filler to insure complete coverage within the seam. Immediately remove all ex ess filler after the seam is formed. Before calking a joint, see that the area to be calked is clean and free of all loose particles and has a suitable backstop. Backs of grooves can be packed with rope yarn to provide a backstop. The entire groove ~hould be coat ed with sealer (Fed. Spec SS-S59) or as recommended by manufacturer of 


calking compound, and calked. Calking should be applied with a gun to force the calking into the groove with sufficient pressure to expel all air and fill the groove solidly. 
c. 
Adhesives. Adhesives are used to bond metals to ·wood, glass, r ubber, insulation, masonry, and other metals (MIL SPECS. MIL-A928, MIL-A-14443, MIL-A-1154, MIL-A45059, MIL-C-3316, MIL-C-1219, and MIL-A8623). Although bonding is the primary function of adhes ives, many serve dual purposes such as plastic cement (F ed. Spec. SS-S-153) which is used to waterproof and provide a flexible bond to compensate for thermal expansion and contraction. Epoxy based formulations are providing a complete new material for adhesives. They are used to join vinyl, rubber, wood, masonry, concrete, met al, glass, and other substances. Most adhesives are dielectric in nature and poor heat conductors and can be used as heat and electrical insu lation. Before applying adhesives, check the manufacturer's instructions to be sure the adhesive is intended for the materials being joined, that it will serve the intended purpose, and to determine the proper method of application. 

d. 
Maintenance and R epair. Maintenance inspections of adhesives and calking componuds should be conducted twice a year and should be integrated with the routine roofing inspections (par. 45) . Common causes of failure are drying out which shrinks the material causing cracking and loosening, mechanical failure from excessive movement and vibration, water seepage behind the material combined with freezing and thawing which forces calking compounds out of joints, and excessive heat which melts some compounds, permitting them to lose their strength and flow out of joints. Compounds that have become dry and cracked must be replaced. When replacing adhesives and calking compounds, all traces of old compounds must be removed with scrapers and solvents before the new compounds are applied. Sealers and calking compounds should be painted to prolong their life. 


Section IV. JOINTS AND FABR ICATION 
24. General fasteners, soldering, brazing, welding, and 
This section deals primarily with the methods seaming are discussed with respect to types, of joining sheet metals together. Mechanical uses, methods, and applicable materials. 
AGO 8488A 

25. Mechanical Fasteners The three common type of fasteners used with sheet metal are nails, screws, and rivets. Less common but still widely used for specific applications are cleats, hidden fasteners, and reglets, The factors governing their use are strength, cost, and types of material being joined. The composition of the fastener is also important, especially when there is a possibility of galvanic corrosion. Fasteners should be of the same material or a compatible material as the metal being joined. Fasteners should also be of stronger material than the metal being joined since they are required to absorb the 
same stress as the sheet metal with less crosssectional area. 
a. Nails . The primary use of nails is to fasten sheet metal to other materials, usually wood. Generally, except for roofing and siding, nailing should be confined to sheet metal having a width of 12 inches or less, and to one edge of the sheet to prevent loosening or tearing caused by the stress created by expansion and contraction. ails should be spaced evenly at 4inch intervals along the edge and a sufficient distance from the edge to prevent tearing 
(usually 1/2 to 1 in.). Nails should be driven until the head makes firm contact with the sheet metal. Overdriving will cause the head to dent or bend the metal, resulting in an enlarged hole or torn sheet. Various types of nails (fig. 10) have been developed for specific jobs and should be used for the purpose indicated. Various types of self clinching nails are also used where anchoring is difficult. 
b. Screws. Screw type fasteners are used where extra holding power is desired, where fabricated components are likely to be removed or dismantled periodically, or areas of vibration where other type fasteners are impractical. 
(1) 	Types of sc1·ew fasten ers. The job itself will determine the type of screw used. Sheet metal screws are the most common and are used to reinforce seams and attach objects to sheet metal. Wood screws are used to secure sheet metal to wood or in some cases wood or lead plugs. Drive screws are used to secure small objects to heavy gage sheet metal or metal plates. Bolts and nuts, or lag bolts, are used 
for 	maximum holding power. Figure 
11 	illustrates the various types of 
screw fasteners and their uses. 
(2) 	Types of heads. Screw heads vary in shape and slot type. Common head shapes are illustrated in figure 11. The roundhead is the most versatile and is commonly used because of its flat bearing surface which prevents pulling through lighter gage metal. Flatheads 
""""' ~ 
INSULATED SIDING NAILS 
CEDAR SHAKE NAILS 
., 
CEDAR SHINGLE NAILS 
ASBESTOS SHINGLE NAILS·o/t~HEADS-NEEDLE POINTS 
-E3 "'""' "' 1 
GYPSUM LATH NAILS 
<I 	iiilliiliil! 11 
WOOD SIDING NAILS -CASING HEADS 
I II 	I I I I 
!J 
WOOD SIDING NAILS-SINKER HEAD 
.C! ::::;: ~ 
SHINGLE NAILS-GENERAL PURPOSE 
<1. 	:::::::::: ~ 
ROOFING NAILS-LARGE HEAD-PLAIN SHANK 
ROOFING NAILS-NEOPRENE WAStiER ATTACHED-PLAIN SHANK 
~~ 

ROOFING NAILS-NEOPRENE WASHER ATTACHED-SCREW SHANK 

<3111111111111""'~ 
ROOFING NAILS-BARBED-SHANK WITH LEAD WASHER 
<I 1""'8 
ESCUTCHEON PINS 
Fi gure 10. Types of nails. 
AGO 8488A 


w0 WOOD SCREWS MACHINE SCREWS 
T w i V V V V 

ROUND FLAT OVAl TRUSS ROUND FLAT OVAl HEAD COUNTERSUNK COUNTERSUNK HEAD HEAD COUNTERSUNK COUNTERSUNK 
METAL SCREWS 
l l T T T 
ROUND FlAT OVAL TRUSS PAN-
HEAD COUNTERSUNK COUNTERSUNK HEAD HEAD 

HEAD AND POINT STYLES 
NUTS AND BOLTS SlOTIED PHILLIPS HEAD RECESSED HEAD SHEET METAL SCREWS 
CID ® 
~1~11 
Fl o lh• od Bol l Roundh•od Boll 
t i 
> C')  Type "A"  Type " 8"  
0  GIMLET POINT  BLUNT POINT  
00...  
00  
00 >  Figure 11.  Screw  type fasteners.  


a r e counter sunk and cannot be used with the lighter gage metals. Their use is limited to heavy gage sheets and plates where a screw head protruding past the surface of the metal is objectionable. Oval-heads are countersunk and are mostly used to secure decorative objects. Panheads are the most common type head used on sheet metal screws. They provide the maximum bearing surface at the base of the head to prevent pulling through the lighter gage metals. Screw heads are further divided into slotted and cross-recessed 
(Phillips). Slotted heads are the most common and provide a better grip between the screwdriver and screw. Cross-recessed heads prevent the screwdriver from slipping out of the head and are used where damage from a screwdriver will mar a decorative finish or puncture lighter gage metals. 
c. Rivets . Rivets are used where strong joints are r equired and brazing or welding is not practical. Common types of rivets (fig. 12) are flathead, roundhead, countersunk head and tinners. 
u IT TI IT 

FLAT ROUND UNIVERSAL MUSHROOM 
HEAD HEAD HEAD HEAD 

TI 	TI 

100° FLAT  60° OVAL  
COUNTERSUNK  COUNTERSUNK  
Figure 12.  

A further distinction is made by a tubular or solid shank. Solid rivets are usually installed by hand and tubular rivets by machine. Flathead rivets are used for lighter gage sheet metal to prevent the rivet from pulling through the metal. Roundhead rivets are used on heavy gage metals for high strength. Countersunk rivets are used on heavy gage sheets to provide a flush surface. Tinners rivets are used when the seam or joint is to be soldered or brazed after riveting. 
(1) 	S election of size . Rivet sizes are determined by two methods. The pound weight is the weight of 1,000 rivets. For example a 2-pound rivet weighs 2 pounds per thousand rivets. The other method is the actual size of the rivet in diameter and length. The diameter of the rivet should be 21/:! to 3 times the combined thickness of the metals being joined. The length of the rivet should be equal to the combined thickness of the metals being joined plus 1% times the diameter of the rivet. This leaves enough of the rivet projecting through the metal to form a head. 
TI TI TI 
BRAZIER BUTION 78° FLAT 78° OVAL HEAD HEAD COUNTERSUNK COUNTERSUNK 
IT 

MODIFIED TINNERS RIVET BRAZIER 
Types of rivets. 
AGO 8488A 

(2) 	
Spacing of rivets. Rivets should be spaced from the edge of t he metal a minimum distance equal to twice the diameter of the rivet. The minimum spacing between rivets should be sufficient to allow driving without interference or about three times the diameter of the rivet. The maximum spacing between rivets is twenty-four times the thickness of the sheets being joined. For exceptionally strong joints the rivets may be staggered in two rows. 

(3) 	
Riveting practices. Holes for rivets should be drilled or punched and be of sufficient size to permit a snug fit for the rivet. Insert the rivet into the hole and place a solid block against its head. Place the deep hole of the rivet set over the rivet and strike a blow with a hammer to draw the metal together. Remove the rivet set and flatten the end of the rivet with a hammer. Place the cup of the rivet set over the flattened rivet and strike several hard blows to form a head. 


d. 
Cleats. Cleats are strips of metal, 2 inches wide of the same metal and gage as the sheets being secured (fig. 23). The cleat is secured with two nails at one end with the remainder of the cleat folded with the seam of the sheets being joined. The actual development of the cleat is part of the seaming operation and is covered more thoroughly in paragraph 30c. 

e. 
Hidd en Fasteners . Hidden fasteners are devices soldered or brazed to the backs of sheets to secure them without having the fasteners exposed on the face of the sheet. Such devices include screw-type fasteners, hooks, clips, and special locking devices. 


26. Solderi ng Soldering (Military Specification MIL-S6872) is a process of joining two metals together by melting a third metal (at temperatures below 1,000 °F .) and allowing it to flow between the metals being joined. The bond formed is mechanical and relatively weak; therefore it is primarily used as a sealer or for joining where strength is not required. In sheet metal 
work solder is generally used in conjunction with seams to provide a watertight seal and to 
----. 
strengthen the seam. The process of soldering consists of cleaning the two metals, applying flux, heating the two metals to the melting temperature of solder, applying the solder, and allowing the metals to cool slowly and undisturbed. 
Caution: F umes generated by t he heating of flux are usually acid or toxic. Soldering operations should only be accomplished in wellventilated areas. P ersonnel must take every precaut ion to avoid breathing t hese f umes. 
a. Types of Solder. 
(
1) 	Half and half tinners solder consists of one-half tin and one-half lead. This alloy has a melting temperature of 415 °F. and a sheer strength of 5,240 psi (pounds per square inch) and is the most frequently used solder. 

(2) 	
Two-thirds tin and one-third lead is used where increased strength is required. Thi~ alloy melts at 360 °F. and has a sheer strength of 6,230 psi and is used for joining stainless steels. 

(3) 	
Soft solder contains 95 percent tin and 5 percent antimony and is used for soldering brass and copper and places where a low melting temperature is required. 

(
4) 	Silver solder is used where more than ordinary strength is required. Silver can be added to copper-zinc brazing alloy or alloyed with copper in varying compositions to obtain a desired melting temperature. Besides being strong, these alloys are mallable, ductile, corrosion resistant, and nontoxic which makes them suitable for kitchen equipment and food handling machines lead is unsatisfactory. 

(5) 	
Aluminum solders are alloys of tin, zinc, and small quantities of aluminum. Small quantities of copper and lead are sometimes added. These solders are strong and ductile and are classed as hard solders requiring a blow torch for application. 


b. Types of Flux. Flux (Fed. Spec. 0-F506) is used to remove the existing oxide film on metals and to prevent further oxidation during the soldering process. The use of flux is necessary to insure a good bond between metal and solder. 
AGO 8488A 
(1) 	Raw muriatic acid is frequently used on galvanized surfaces and zinc as a flux and on other surfaces as a cleaner before applying flux. This acid destroys zinc and zinc-coated surfaces rapidly and must be washed off im
mediately after soldering is completed. 
(2) 	
Cut muriatic acid, also known as zinc chloride, is made by adding small pieces of zinc to raw muriatic acid until the solution is saturated and the reaction ceases. Cut muriatic acid is used as a flux for terne plate, copper, brass, black iron, babbit, block-tin, monel, copper-nickel alloy, bronze, pewter, and nickel. It is also used on stainless steel following an application of raw muriatic acid and on aluminum after the surface has been tinned. 

(
3) Block or powdered rosin is less corrosive than acids and is preferred for tin and tin or lead coated (pretinned) surfaces. The block and powdered forms are applied after the metal has been heated. 

(
4) 	Tallow is used for soldering and burn

ing lead and in some cases, soldering aluminum. 

(
5) 	Soldering paste is a commercial product used primarily for copper wires and zinc. 

(6) 	
Sal ammoniac is generally used with a cut acid for tinning operations on large surfaces and as a flux for black iron. 

(7) 	
Phosphoric acid is an effective flux for stainless steel and usually produces better results than raw and cut muriatic acid. 


c. Soldering Equipment. Equipment necessary for soldering includes solder, flux, source of heat, soldering coppers, and cleaning equipment. 
(1) 	Soldering copper. Soldering coppers, commonly called soldering irons, are made of copper attached to an iron shank with an insulated wood handle. 
The weights and shapes of these coppers vary to suit the different soldering operations. Small, light work 
would require a small iron with a sharp point. Heavy work such as roof seams would require a large iron with a blunt point. The copper should be cleaned and dressed with a file if necessary, heated, dipped in flux, and pretinned before soldering. Untinned and undressed soldering coppers have poor heat transfer and usually result in an unstatisfactory soldering job. 
(2) 	
Soure of heat. Sources of heat vary from electric heating elements built into the soldering copper to blow torches. For shop work, the coppers are usually heated in bench mounted gas or electric furnaces. For on-thejob work, they are usually heated in gasoline-fired furnaces, stands adapted to blow torches, or charcoal pots. 

(3) 	
Cleaning equipment. Cleanliness is essential both before and after soldering. Before soldering the work must be free of all paint, grease, dirt, and corrosion to insure a good bond and prevent voids in the solder. After soldering, the work must be cleaned to prevent corrosion and staining by the flux. Corrosion can be removed with wire brushes, sandpaper, or emory cloth. Paint and heavy deposits of grease can be removed with solvents 


(MIL Spec. MIL-C-11090). Dirt and light grease should be removed with water and detergents (Mil. Spec. MIL-D-16791) . After soldering, all traces of flux should be removed with solvents followed by a thorough washing with detergent and water, and drying with clean, dry cloths. 
Note. Naphtha (MIL-N-15178), kerosene (Fed. Spec. VV-K-211) diesel oil (Fed. Spec. VV-F-800), and turpentine (Fed. Spec. TT-T-801) may be used as solvents. However, these solvents are flammable and should not be used if nonflammable, lowtoxicity, solvents will serve the purpose equally as well. 
d. Soldering Practices. Good soldering pract ices include: keeping the work clean; pretinning metals that are not coated with lead or 
zinc; using the proper solder and flux (a and b above) ; keeping the equipment in serviceable condition; drawing the copper along the work 
AGO 8488A 
slowly to allow full penetration of t he heat; not 28. Welding
disturbing the work until the solder has hard

Welding is the process of joining two metalsened; removing all traces of flux after soldertogether by heating them to their melting teming. Insufficient heat or moving t he joint be
perature and fusing them together either by
fore the solder is completely solid will result in pressure or by filling the joint with a metala cold joint. Good soldering points are smooth similar to the metals being joined. Welding isand uniform. Cold joints have high uneven done at extremely high temperatures and prospots and appear to have a crystallized strucduces a high strength joint. The melting and
ture. 
solidifying of the metal in the weld area isextremely rapid (especially for arc welding)
27. Brazing 
and small quantities of air and slag do not haveBrazing is a method of joining two metals sufficient time to separate from the metal.together with a filler rod, usually copper or 
Arc welding is usually not recommended wherecopper alloy. Unlike solder, the filler rod water tightness or corrosion resistance is reforms a fused joint of high strength between quired because of the porosity of the weldthe two metals. For nonferrous metals, a caused by the entrained air and foreign parbrazed joint is often stronger than the parent ticles.metals. Brazing is often pr'eferred to welding 
Caution: Fumes generated by the heatingbecause the joint formed is nonporous, water of welding flux are usually acid or toxic. Weldtight and highly corrosive resistant. 
ing should only be accomplished in well-ventiCaution: Fumes generated by the heating lated areas. Personnel must not breathe these
of brazing flux are usually acid or toxic. Brazfumes.
ing operations should be accomplished in well

a. Gas Welding. Gas welding is accomplishedventilated areas and personnel must avoid by using a torch to heat the metals to theirbreathing such fumes. 
melting temperature. Oxy-acetylene torches
a. Uses of Brazing. Brazing is adaptable to are used for most metals. Hydrogen and oxsteel, cast-iron corrosion-resisting steel, brass, ygen are generally used for aluminum.bronze, and aluminum. Standard copper alloy b. Electric W elding. Electric welding is acbrazing rods are used for iron, steel, cast iron, 
complished through the use of alternating orbrass, and bronze with borax or borax comdirect current electricity of low voltage andpounds for flux. Special silver-copper rods high amperage. Electric welding sets consistwith phosphoric acid for flux are recommended of a motor generator or transformer to confor corrosion-resisting steel. Special aluminum vert conventional alternating current to directalloy rods and fluxes are required with alumcurrent with the required voltage and amperinum. age; necessary cables to transfer the current
b. Bmzing Practices. Surfaces to be brazed to the work ; and clamps or holders to securemust be clean and free of paint, grease, and oil one cable to the work and the other to a weld(use same procedure as for soldering (par. ing filler rod or carbon pencil. 26c (3) ) . The flux is generally applied to the (1) Spot welding. Spot welding is combrazing rod by heating the rod and dipping the mon ly used in the fabrication of sheetheated portion into the flux. The work must be met al items that do not require waterproperly aligned and clamped; the use of chill tight joints. Spot welding is accompbars to prevent the heat from spreading is reclished on a special welder that hasommended. The work is heated with an oxytwo electrodes mounted on the front.acetelyene torch to a temperature above the The seam to be welded is placed bemelting point of the brazing rod but less than tween the electrodes and an arc isthe melting point of the work. The flux coated struck. Pressure is applied immedirod is fed into the joint while the heat is being ately to complete the weld.applied. The chill bars and clamps should re(2) Metal arc welding. The metal arcmain in place until the work has cooled to keep process utilizes a filler rod clamped inthe stress and heat in the area of the brazing. an insulated holder which, in turn, is 
34 AGO 8488A 
connected to one terminal of the power source (usually the positive). The other terminal is connected to the work. An arc is struck between the filler rod and the work, creating an intense heat which melts the parent metals and filler rod, fusing the three metals together. 
(3) 	Carbon a1·c we lding. Carbon arc welding incorporates a corbon rod or pencil to create an arc in the area of the weld. A metal filler rod is placed in the arc and allowed to flow into the joint where it is fused to the parent metals. Carbon arcs are commonly used for brazing and cutting where neat cuts are not required. 
c. Atomic Hydrog en W elding . Atomic hydrogen welding is accomplished between two tungsten electrodes in an atmosphere of hydrogen. The process depends upon the intense heat developed when atomic hydrogen, which has been dissociated from molecular hydrogen by the arc formed between the two tungsten elect rodes, recombines to form molecular hydrogen. The heat produced in this manner is more intense and better controlled than the heat produced by an oxy-acetylene torch. The weld produced is smoother and less porous than the welds produced by other arc welding proc
esses. 
d. Fille1· Rods. Filler rods are produced commercially and are precoated with the proper flux corresponding to the composition of the rod. The flux coatings are generally composed of metal oxides, silicates, organic materials, and carbonates. Rods should be of similar material as the metal being welded, with the diameter approximately equal to the thickness of the work. 
e. Inert Gas-Shielded Elect1·ic A 1·c W elding. 
This method of electric arc welding is used extensively for welding stainless steels and aluminum without damage to the surface finish. Welding is accomplished between two tungsten electrodes with a blanket of inert gas (helium or argon) to shield the welding zone from oxides and other impurities during the welding operation. The use of inert gas shield eliminates the necessity for flux and produces a smoother, cleaner weld than other electric arc welding methods. The elimination of fumes, spatter, salts, and other flux residues tends to reduce cleanup operations and minimizes weldmetal porosity. 
29. 	Joints 
Joints are formed when two or more pieces of sheet metal intersect. Methods of joining sheet metal at these intersections include soldering, brazing, welding, mechanical fasteners and seams. Seams are the most common method of joining the lighter gage metals and are covered in detail in paragraph 30. The remaining joints are secured by welding, brazing, and mechanical fasteners and include butt joints, lap joints, corner joints, and flange joints. 
CL Butt Jo ints. (fig. 13). Butt joints used to join heavier gage sheet metal where a smooth, flat surface is desired. Plain butt joints are either brazed or welded and seldom need reinforcement at the joint since the welded or brazed portion is as strong or stronger than parent metals. The use of mechanical fasteners (screw type or rivets) and spot welding require the use of angles, tees, channels, or heavy strips to reinforce the joint. Rivets (par. 25c) are the most common method of securing butt joints. 
b. Lap Joints. (fig. 14). Lap joints are used where a stronger joint or water tight joint is desired. When strength is not a factor, lap 

osssssnzzm MSSST"'"'" 

CHANNEL 	TEE 
f??Z??~SSSSSS\ 
ANGLEDOUBLER 
iSSSSSSSSSSii?ZZZ?/222?/ 
PLAIN BUn 
Figure 13. Typical details of butt joints. 
AGO 8488A 


joints are usually soldered. When moderate strength is desired, the plain or joggled lap joint may be used. For high strength and rigidity, a reinforced lap joint is necessary. 
c. Flanged Joints. (fig. 15) . Flange joints possess strength and rigidity without the necessity of additional reinforcement. Flange joints are usually prefabricated, easier to install, and neater in appearance than other joints incor porating mechanical fasteners. 
d. Corner Jo ints. Corner joints can be of the flange type as shown in figure 15 or of t he reinforced or welded type as shown in fig ur e 16. Flange corner joints are the most commonly used and have sufficient strength and rigidity for most jobs. Where high strength a nd rigid-
FLANGE DOUBLER 
ANGLE 
CHANNEL TEE 
VZZZZZJ<(~SS$SSSSSS$$$$1
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JOGGLED
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"-!.,.~~+-----~ NOTCH DEPTH TO SUIT BRAKE WIRE OR
JOGGLE TO eND LAP
SUIT --+---..,l 
EXAMPLE OF LAYOUT 
Figu1·e 14. Typical details of plain and rein[o1·ced lap joints. 
36 AGO 8488A 

VZ7%ZZZZZZ~ssssssssss~ 

PLAIN 
HEMMED 

INVERTED PLAIN  HEMMED  ANGLE  
PLAIN  DOUBLE  
Figure 15.  Typical details of flange joints.  

ity are required, the reinforced joints (fig. 16) should be used. Welded corner joints are not recommended where excessive vibrations will be encountered. 

30. 	Seams 
Seams are a common method of joining sheet metal, uiilizing folds at the edges of sheet metal instead of mechanical fasteners to secure the joints. Seams are usually water tight, but for roofing and structural application, the edges to be seamed are pretinned before the seam is formed and completely soldered after the seatn is formed. In cases where soldering is undesirable, calking or sealing compound is folded into the seam, or sealing compounds and tapes are applied over the finished seam. Carefully plan all seams before proceeding with the work, as most sheet metals cannot be straightened and refolded without splitting or cracking. 
a. Types of Seams. Typical seams used in the fabrication of ductwork, hoods, canopies, and similar items are shown in figure 17. The Pittsburgh or hobo seam is the most commcln and many shops are equipped with a special forming machine for fabricating this seam. The remaining seams can all be formed on a standard bending brake machine. 
(1) 	Roofing seams. Common roofing seams include the single lock and double lock for flat seam roofing (par. 34a), standing seam for standing seam roofing (par. 34b), and batten seams for batten seam roofing (par. 34c) . The single and double lock seams are either soldered or calked to insure water tightness. Standing and batten seams are left free to allow for linear movement caused by thermal expansion and contraction. The development of the lock seam is illus-

AGO 8488A 


RIVETED OR BOLTED 
WELDED 
Figure 16. Typical details of corne1· joints. 
trated in figure 18 and the standing and batten seams in figure 19. 
(2) 	Slip or bar seams. (fig. 20). Slip seams are made by driving or forming a strip of sheet metal over the mating flanged edges of the sheets to be joined. In some cases the edges of the metals being joined ar e left flat and inserted into a slip joint. This type of seam requires sheet metal screws to secure the slip j oint to the sheet metal. Slip and bar seams are generally used in ductwork (par. 46) 
• to join pieces of duct together, and occasionally they are placed as expansion joints or for ornamental purposes. 

b. Stiffeners. (fig. 21). Stiffeners are placed along the edges and in the body of metal sheets to attain strength and rigidity over large flat surfaces. Edge stiffeners are used on metal shelves, hoods, trim and other items having an exposed edge that is subject to stress or handling. Body stiffeners are placed at 18-to 24inch interval~, running the full length of the sheet in the direction of the stress to prevent 
AGO 8488A 



-jl/4"f
ljSSSSSS-?17%772)
pzzzz~ 
\SSS$\3 
DOUBLE SEAM 
GROOVED FLAT
PLAIN FLAT 
INSERT DOUBLE SEAM 
PITTSBURGH OR HOBO SEAM 

r-~.. 
POCKET NONWATERTIGHT FLANGE CONNECTIONS 
Figure 17. Typical details of common seams. 
Y2" r 
STEP 2
STEP I
STEP I 
@ DOUBLE LOCK SEAM
(l) SINGLE LOCK SEAM 
STEP  I  STEP  2  STEP  3  STEP  4  
@  DEVELOPMENT  OF  DOUBLE  LOCK  SEAM  WITH  CLEATS  
Figure 18.  Development of lock seams.  

AGO 8488A 

S TE P 
S TEP 2 ST EP 3 
STEP 4 
DEV E LOPM E NT OF STAND I NG . SEAM 
STEP 2 STEP 3 
ST EP 4 
DEVELOPMENT OF BAT T EN SE AM 
NOTE : VARY BEVEL OF BATTEN TO PROVIDE 
SPACE FOR EXPANS ION (TABLE 2) 

STEP 5 
Figure 19. Development of standing and batten seams. 
buckling or noise from stress or excessive viness as the metal being secured. The width bration. Another method of eliminating noise should be 2 inches and the minimum length 3 and buckling in flat sheets is cross breaking inches. Maximum spacing of cleats is 12 inches (fig. 22). Cross breaking is a comm n practice from center to center. One end of the cleat is in ductwork for light gage metals larger than secured to the building surface with two nails 18 inches square. and the end of the cleat is folded over the head of the nail. The other end extends to the outer 
c. Cleats (fig. 23). Cleats are used in con
edge of the sheet metal and is formed as an 
junction with seams to secure the sheet metal 
integral part of t he seam as shown in fig ures 18 
to flat surfaces (walls, roofs, etc. ) . Cleats 
and 19. If the seam is to be soldered, the cleat should be made of the same material and thick-must be pretinned before installation. 
AGO 8488A 

SSSSSSSSS $ SSSSSS' 
ISS$ $~~~11$
S $$$$$$\ 
/// / 
·m'<r "'"'"'r 
vzzzzz~sss;,ss•
v/2/?~SSSSSSSSSj 
Figure 20 . Typical details of edge and body slip and bar seams. 
AGO 8488A 
VZZZ??ZZ?ZZZZZ~ 1'22777222 < 2772~ 
SINGLE HEM DOUBLE 
k 2 2 22 2 2 2 ( , z 2 2 2 2 zaOfi2:z.N 
rzzzzzzzzzzzzzzz~ ~ \ Z?Zt ?Z?%72~ 
HALF ROUND HOLLOW HAT BAR SOLID SPLIT PIPE 
BOXED EDGE FLANGE 
ANGLE STIFFENED DOORJAMB 
EDGE STIFFENERS 

\11 111111~ 
<2222222~~2ZZZZ3 
BEAD OGEE SWEDGE 
CHANNEL PLAIN 


~::::::::::~ 
CHANNEL BAR FLANGED V BAR HOLLOW HALF ROUND 
TEE ANGLE BODY STIFFENERS 
Figure 21. Typical details of edge and body stiffeners. 
AGO 8488A 

CLEAT DETAILS 
FLAT-LOCK SEAM AND CLEAT 
ABOUT 2 " 
Figure 22. Cross broken flat surface. 

DOUBLE -LOCK SEAM WITH CLEAT 
Figure 23. Typical details of cleats. 

Section V. INSTALLATION , MAINTENANCE, AND REPAIR 
3 I. Expansion Joints 
Expansion joints are installed to absorb the thermal expansion and contraction of the sheet metal and the building to which it is attached. In many cases, the nature of the installation provides for thermal movement through the use of small sheets with standing, batten, and loose lock seams. However, in long continuous runs, expansion joints are necessary to prevent buckling of the metal or tearing of the seams. Types of expansion and contraction joints should be the flanged U, the slip, loose locked, or manufacturers recommended design, spaced as needed for thermal movement expected. The actual movement of the metal can be calculated from table 2 (par. llc). Metal that is exposed to t he direct rays of the sun should have an additional 50 ° F. added to its temperature to compensate for its absorption of radiant heat. Consideration must be given to temperature at the time of installation to determine whether the allowance should be made for expansion, contraction, or both. The expansion joint in figure 24 was installed midway of its expected temperature range and illustrates the position at minimum and maximum temperatures. The dimensions shown are sufficient for all sheet metals at intervals of 30 feet over a temperature range of 150° F. 
32. Cornices and Belt Courses 
A cornice is a projection from the vertical wall of a building and is an architectural rather than a structural item. Cornices are often used to house built-in gutters and leaders 
(par. 35) on large permanent or monumental building where the larger gutters need extra support and their presence would distract from the appearance of the building. Belt courses, however, are structural rather than arctitectural. The belt course is located where the construction material changes or the structural method varies. Examples of this would be a stone masonry wall for the first two stories of 
AGO 8488A 


. . 	.

5 5 	5
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1-	-, ,
~ 

-~u~Lf -1 ~&·~s;;L111~j 
~;

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TOPANGLEI LAP LAP 	p 
<I) 1;4·
-I·-	--31:-
--1MINIMUM 

~ 	CLEARANCE
1);: 
j 

~ A 	A 
_r~ 	_jt~ 
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l 

A. AT INSTALLATION B. EXPANDED C. CONTRACTED 
Figure 24. Movement of expansion joints. 
a building with the remainder of the building finished in red brick, or a tall building with thick lower walls for support changing to lighter walls at the upper levels. A definite joint is made where t hese changes occur, and a belt course is installed to drain the water away from the joint while at the same time provide a decorative effect to hide the joint. The top surface of the cornice or belt course is sometimes covered with 20-ounce lead-coated copper; the outer edge of the surface covering is locked into an edge strip (par. 33h(l)) and the back edge is turned up on the wall or parapet to form a base flashing (par. 33a). Flat sheet covering should be laid with locked and soldered cross seams with a 3-inch loose-locked jointed filled with plastic cement at intervals of not more than 8 feet. Additional looselocked joints should be placed not more than 8 feet from an internal or external corner. Miters and joints should be carefully fitted, reinforced, riveted, and soldered. 
a. Cornices. Cornices are constructed of wood, stone, terracotta, brick, and sheet metal. Most cornices can be treated with flashing as shown in figure 25 to prevent seepage of water into the wall, or with gutter linings as described in paragraph 35 to provide water drainage for the protection of the lower wall against strains and water damage. Sheet metal cornices are often used because of light weight, ease of construction and durability. Materials for cornices include copper, monel, stainless steel, aluminum, and galvanized iron. The followi g factors must be kept in mind when constructing sheet metal cornices. 
(1) 	
Material must be at least 20-ounce lead coated copper or equal, except on wood cornices where the edge strip will be not less than 24-ounce. 

(2) 	
All fasteners and supports must be of compatible material as the cornice or properly insulated (par. lle). 

(3) 	
Cornices greater than 24 inches wide should have a cap and base flashing (par. 33a) at the wall instead of a continuous run of metal from wall to edge. 

(4) 	
Sheets should be secured with screws and lead washers instead of nails. Sheets wider than 36 inches should' have enlarged holes around the screws and caps soldered over the screws. 

(
5) 	Longitudinal seams should be loose locked and filled with calking compound or mastic sealers. Expansion joints must be placed at intervals not greater than 30 to 48 feet. 

(6) 	
Tight seams subject to stress must be riveted and soldered. 

(7) 	
Ornaments and decorative components are soldered to plain surfaces. Large heavy items are riveted and soldered. 

(8) 	
Drip edges must be provided where setbacks occure at the bottom of vertical faces. 



44 	AGO 8488A 




. .
c:

rr::l

DETAIL AT EDGE 
STONE CORNICES 

CEMENT 
WASH 
FLUSH STONE BE L T COURSE
GABL E COPING

TERRA COTTA CORNICE 
: •.
. 
·. •·· 
.. ~ ~ 
.
. 

.. 
., . 
.. 
' ~_:~_!;-'-._ _ --..L 
BELT COURSE AT 
MOULDED BRICK 

BELT COURSE
STONE AT FLOOR LINE 

STREET LEVEL 
BELT COURSE 

BELT COURSr 
CORNICES B BELT COURSES 
Figure 25. Flashings jo1· cornices and belt cou1·ses. 
AGO 8488A 

b. Belt Courses. Belt courses, because of their structural aspects, are seldom constructed of sheet metal. The treatment of belt courses (fig. 25) is identical to the treatment of through wall flashing (par. 33c) . 
c. 	Maintenance of Cornices cmd Belt Courses. 
Periodic (at least twice a year) inspections should be made for cleaning and physical damage. Cornices, especially those with built in gutters, collect dirt and foreign matter which plugs the gutter drain or causes water to flow off the edge of the cornice and, if blown against the side of the building, may cause staining. All flashings must be checked carefully to insure water tightness. Water seeping behind stone cornices and belt courses, combined with the effects of temperature change and freezing, will break the masonry bond securing the cornices and belt courses. Loose cornices and belt courses provide a potential safety hazard to both propert y and personnel and must be reported and repaired immediately. 
33. 	Flashings Flashing is the name given to metal or other suitable material used in structures to prevent the seepage of water through critical points or areas. Flashings are primarily used over masonry and at joints formed at the intersection of sloping roofs or roofs and walls. The most common metal used fo r flashing is copper; however, consideration must be given to the surrounding metals and the effects of possible copper staining. Aluminum, monel, stainless steel, clad metals (lead, and zinx coatings, etc.), and sheet lead are a lso used (see table 10, app. II for thickness of various sheet metals). Usually, the flashings are installed with only one edge secured ; the other edge is left free or attached by some method that will allow for expansion and contraction. Straight runs of flashing less than 30 feet but more than 8 feet should have a 3-inch loose-locked, slip type expansion joint (as shown in fig. 37) filled with plastic cement installed at the center of the run. Longer runs of flashing should have an additional expansion joint for each addit ional 30 to 48 feet of flashing or portion thereof. Intermediate joints between expansion joints are locked and soldered. Since it is impossible to 
cover every type of flashing application, the following discussions will cover the basic fundamentals involved with each type of flashing along with the more common application. 
a. Cap, Bas e and Wall Flashings . Cap, base, and wall flashings are used to protect the joint formed at the intersection of a roof and a vertical wall. The base flashing protects the joint while the cap flashing protects the portion of the base flashing that extends up the wall. The overlap between the two flashings should be at least four inches. Figure 26 illustrates a few of the typical installations of cap and base flashings used in conjunction with the various type:;: of walls and roofs. 
(1) 	
Cap flashing. Cap flashings are formed with the upper edge secured in such a manner as to provide a water tight seal between the flashing and attaching surface. The lower edge extends down over the base flashing a minimum distance of four inches and is folded under one-half inch for stiffness and is formed so as to keep a constant pressure against the base flashing. Methods of securing the upper edge to provide a water tight seal include reglets (h(8) below), setting the edge in a brick wall, forming the cap flashing from an extension of a through wall flashing (c below) and extending the end not less than 2 inches under a composite wall. On wood construction, cap flashing should extend up under the exterior coverings, such as shingles and slate, not less than 2 inches above the butt of the second course and not less than 4 inches above the roof. These methods are illustrated in figures 26 and 27. 

(2) 	
Bas e flash ings. Base flashings are formed to fit the joints between a roof and vertical wall to provide a waterproof covering for the joint. The upper edge of the base flashing extends up the wall a minimum distance of 8 inches and is protected with a cap flashing. On sloping roofs, the lower edge extends out onto the roof ing surface not less than 4 inches and is folded under one-half inch for stiffness. Typical installations and methods of securing base flashings are illustrated in figure 26. On composi-


AGO 8488A 
> 
C"l 
0 
~ 
00 00 
> 
~I 
SHINGLED VERTICAL
STEPPED SIDEWALL BRICK VERTICAL 
WALL FLASHING
FLASHING-CAP 8 BASE WALL FLASHING 
Figure 26. Typical installations of cap, base, and wall fla shings. 
~ 
..... 
tion or built-up roofs, metal base flashings are generally not recommended. Instead, the roofing composition is extended over the joint and up the wall not less than 8 inches as shown in figure 27. The joint is furtr_er protected by a layer of either 4-inch selvageedge mineral-surfaced asphalt roll roofing (Fed. Spec. SS-R-630), bituminuos impregnated cotton fabric (FS-HH-C-581, or 591), woven glass fabric, or 3-ounce sheet copper sandwiched between protective coverings. This top sheet is cemented between its end laps, and between the underlying felt with plastic roofing cement (FS-SS-C-153, type I or II) applied with a trowel at the rate of 50 pounds per 100 square feet of surface. Mineral-surfaced roofing strips are cut from the width of the material (36 in. wide) and laps are made the width of the selvage. The other materials are installed in strips about 16 inches wide and 5 feet long with ends lapped 6 inches. When metal base flashing is required it should be coordinated with the roofing work and installed accord
ing to current specifications for new construction. In such cases metal base flashing should be installed after three layers of roofing or plastic flashing felt have been set in the angle formed by the roof and vertical surfaces. Strips of metal base flashings of the required width should be rounded, not bent at sharp angle, into the proper shape and imbedded in plastic roofing cement in the angle against the three layers of felt. The edges of such base flashing on wood or gypsum roofs is held in place on the roof side by roofing nails spaced 3 inches on centers and the tops covered plastic roofing cement before balance of roofing is installed. The ends of such strips are joined and treated as outlined in paragraph 33. 
(3) 	Wall flashings. Wall flashings are combinations of cap and base flashings or, in cases where the upper portion of 
the base flashing is protected by shingles (shingled vertical wall) or where sufficient allowance can be made fo r expansion and contraction, the cap flashing is eliminated and one piece construction is used as illustrated in figures 26 and 28. 
b. 
Hip and Ridge Flashings. Hip and ridge flashings cover the joint formed when two planes of a roof intersect in a hip or ridge. Several types of hip and ridge flashings are shown in figure 29. These flashings are generally performed (except when integrated with shingles) in 8-foot lengths and installed with 3-to 4-inch overlapping or slip joints. Nails are used to secure the shorter section and screws with lead washers for the longer sections. Caps should be soldered over screws on horizontal surfaces or on vertical surfaces where leakage is possible. 

c. 
Through-Wall Flashing. Through-wall flashing is installed in the masonry during the construction of the wall in places where leakage may occur and penetrate to the interior or the wall, or to the lower portion of the wall 


(figs. 25 and 30). Two types of through-wall flashings are used. Type ( 1) goes through and extends beyond the wall. Type (2) is completely concealed within the wall. Type ( 1) flashings are installed to catch moisture running down the inside of the wall and divert it to the outside wall. Type (2) prevents the penetration of moisture by gravity and is generally used above the roof level where the moisture can be passed off to either the outside wall or the roof. Quite often, through-wall flashings are extended to serve a dual purpose as flashing for belt courses (par. 32b) and cap flashings (a above). 
(1) 	
M aterial. Thorugh-wall flashing is usually manufactured performed with special corrugations or embossing which will provide a mechanical bond with the mortar bed. Such embossing should run in two directions to form a mechanically keyed interlocking feature as shown in figure 30. See table 10 for materials and thickness of through-wall flashings. 

(2) 	
Instcdlation. Through-wall flashing is installed with a thin layer of mor-


AGO 8488A 
I 
----~~~~~~~~~i 
BUILT-UP ROOF 
t 
STUCCO STUCCO ON WOOD ON MASONRY 
THRU WALL FLASHING 
Figure 27. Cap and base flashings for composition (built-up) roofs. 
tar both under and over the metal and sloped in the direction the water should drain. The back edge is usually turned up to form a water stop (type (1) flashings only). This turn up must finish at least 1 inch high and preferably 2 inches high. When the flashing extends through the outside 
AGO 8488A 
wall, the outer edge must be folded down to form a one-half inch drip (h below). Sheets should lap at the ends not less than 2 inches. 
d. Spandrel-Beam Flashing. Spandrel-beam flashings are installed where steel beams are used for ~:upport and bracing in masonry structures. The steel beams are usually encased in 

(. 

THRU WALL FLASHING 
NAIL IN LEAD PLUG 
SIDE WALL FLASHING RUBBLE WALL THRU FLASHING TILE ROOF AGAINST BRICK 
PAPER 
WALL 
THRU WALL CAP FLASHING 
NAIL 
THRU  WALL  FLASHING !  WALL  FLASHING  END WALL  
TILE  ROOF  AGAINST  BRICK  TILE  ROOF  AGAINST  FRAME  

F igu?·e 28. Wall flashings for sloping roofs. 
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concrete and form a part of the wall. The steel, concrete, and masonry walls have different coefficients of expansion and the area surrounding the beam will be loose and subject to some movement and stress. The surface to which the spandrel-beam flashing is to be applied is first coated with asphalt-primer and then given a thorough brush coating of asphalt roof-coating. The flashing is applied with 3-inch lap seams cemented with plastic cement. Typical spandrel-beam flashing installations are illustrated in figure 31. Spandrel-beam flashings are usually made of 3-to 5-ounce copper coated with plastic bituminous compounds or laminated with cloth or paper in asphalt to provide a flexible, waterproof material. Other materials include wire mesh that has been sealed in asphalt and coated with cotton fibers, nonmetallic materials (plastics, etc.), sheet aluminum that has been treated similarly to copper, and sheet zinc. 
e. Valley Flashings. Valley flashings cover the joints formed by the intersection of two sloping roofs. Valley flashings are divided into two types. The open valley is the most common and is constructed of 8-foot sheets laid in a continuous run with overlapping seams. The closed valley is installed on shingled roofs with the flashing integrated with the singles. 
(1) 	Open valleys (fig. 32). Open valley flashings are designed with a slight increase in width as the flashing progresses down the slope to eliminate the possibility of trouble caused by water backing up when the valley is clogged with snow or debris. The exposed portion of the flashing is 4 inches wide at the top and increases 1 inch per 8 feet down the slope (i.e., in a 24-ft valley, the top of the flashing is 4 in. wide and the bottom of the run is 7 in. wide). Each side of the flashing extends at least 6 inches under the roofing for the entire run. The top of each sheet is secured with nails on 3inch centers with the ends of sheets overlapping not less than 8 inches. The sides of the sheets are secured with cleats (par. 30c), on 12-inch centers. A metal or treated wood cant strip is usually included to provide 
AGO 8488A 
even bearing for ends of shingles and to contribute to waterproofness of the valley. When the slope of the valley is 4 inches or less per foot or the intersecting roofs are on different slopes, provisions must be made to prevent the water from backing up or washing over the valley and backing up the water on the flatter slope. This is accomplished for extreme conditions by placing additional flashing members on the lower slope by dovetailing them between the shingles and soldering edges of the valley as indicated in figure 33, section AA. For less severe conditions, and inverted V-crimp or other suitable baffle is formed in the valley flashing as shown. Also for valley slopes of 4 inches or less the ends of sheets should be seamed and soldered (fig. 32). 
(2) 	Closed Valleys (fig. 34) . Closed valley flashings are limited to shingled roofs where the slope of the valley exceeds 8 inches per foot. On lesser slopes, closed valleys should not be used, as the snow is held by the rough shingles and as the snow melts the water backs up and runs down behind the flashing. The flashing pieces are cut to fit the joint and the shingles (by use of a template), with a 2-inch extension at the top of the flashing. The extension is either nailed to the sheathing of the roof or folded behind the shingles. The material should be in accordance with table 10, appendix 
II. 
f. Chimney Flashing. Chimneys projecting through flat roofs can be treated with cap and base flashings as detailed in a above. Chimneys projecting through sloped roofs require five types of flashings. The side facing up the slope requires a saddle or cricket to prevent water, snow and debris from settling in the pocket formed at the intersection of the chimney and roof. The sides running with the slope require stepped side wall flashings (cap and base flashings), and the side facing down the slope requires a cap and base flashing, both of which can be of one-piece construction since they are 
5 1 
DETAIL -A 
DETAIL 8 
DETAIL C 
HIP OR RIDGE FLASHINGS BEND UNDER 
R. H. SCREWS 
8 LEAD WASHERS 

I 
LOOSE LOCK 
HIP FLASHING 
Figure 29. T ypical hip and ridge flashings. 
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LINING  
BRICK  LINTEL  STONE  SILL  
·.. ·.  RADIATOR  RECESS  .·. :·.....  STON E  LINTEL  ALTERNATE BRICK LINTEL FOR UNPLASTERED BRICK WALL  

Figure 30. Typical through-wall flashings. 
only secured in the brick work of the chimney. Usually the cap flashing installed around the base of a chimney is formed as part of a through-wall flashing (c above) for added protection to the lower portion of the chimney. All of the flashings are described in this paragraph. The construction and installation of the saddle are illustrated in figure 35. Small saddles are made in once piece with V-shape filler pieces locked and soldered at the end openings. Large 
AGO 8488A 
~addles are flashed in two pieces with a locked and soldered seam a long the ridge. The met al is turned up against the chimney to form a base flashing and is covered with a cap flashing having a 4-inch overlap. The flas hing is carried out under the shingles or into a bu ilt-up roof 6 inches with the edges fo lded back one-half inch to form a water drain. See table 10, a!>pendix II for chimney flashing materials. 
/ .J.-1--1<1--6' CINDER 
BLOCK 

S T ONE LINTE L 
METAL
WINDOW 

SPANDREL WATERPROOF I NG 
DEEP SPANDRE L 

WEEP HOLE 
lEACH ~ TH. 
COURSE 
SHALLOW B E AM OPEN WEB CAVIT Y WALL SPANDRE L CONSTRU ~TI ON 
Figure 91 . Typical spandrel-beam flashings. 
g . Roof Projections (fig. 36). Stacks and sleeve is snug fit with some allowance for expanvents projecting through roofs present difficulty sion and contraction. The bottom of the sleeve in waterproofing si ce the vents and stacks are is usually flared sli ghtly and flanged to provide usually round and made of metal. Generally, a flat surface for soldering to the base flashing. three types of flashings are necessary to waterA cap flashing is formed with the upper edge proof these projections. The base flashing on folded to fit into the stack or vent, and the built-up roofs extends into the roofing composi~ lower edge extending down the outside of the tion 6 to 8 inches and is sealed in plastic cement. stack or vent to form a 4-inch overlap wit h the On sloping, shingled roofs, the upper edge of flashing sleeve. Most stacks and vents are made the base flashing ext ends under the roofing surof cast or galvanized iron; 24-gage galvanized face 6 inches and is sealed in plastic cement; iron or sheet lead is usually recommended for the lower edge is brought out over the roofing stack and vent flashing (except copper is used and extends down the slope a minimum distance in conjunction with copper roofing) . Be sure of 4 inches. The top and side edge~ are turned the flashing and vents are of compatible materiup to form water drains and the bottom edge is als. Other flashings for similar roof projection turned under for stiffness. A flashing sleeve can be treated in the same manner as stack and 
vent flashings except for the cap flashing. In
is constructed to extend up the stack or vent a minimum distance of 8 inches. The top of the many cases the cap flashing will have to be sold-
AGO 8488A
54 
--------~
CANT 	STRIP 
OPEN 
SIDES 

2" CLEATSTRIP 
OPEN VALLEY
STRAP 

PARALLEL SIDES 
ALTERNATE -WOOD CANT STRIP 

Figure 82. Open valley flashings . 
ered to the projection or sealed with plastic cement and clamped. 
h. Misc ellaneous. Flashings are often formed to serve a dual purpose in connection with roof drainage or protection. The following are miscellaneous flashings and adaptations used with flashings. 
(I) 	Edge and drip strips (fig. 37). Edge and drip strips are installed at the 
AGO 8488A 
outer edges of sheet metal coverings on roofs, cornices, belt courses, and parapets to provide a continuous locking edge that permits freedom of movement. The edge strip is formed of a material compatible with the covering, and is secured to the supporting structure with screws spaced not over 12 inches on centers. Lead plugs 


ANGLE OR TE E 
11 TEE 11 
OR" 1ANGLE11 IN VALLEY BAFFLES"CRIMP11 IN VALLEY BAFFLE 
Figure 89. Valley flashings for unequal slopes. 
should always be used in conjunction with screws secured in masonry. The outer edge of the roof or flashing is folded over and locked under the edge strip to form a drip edge. The drip edge provides a surface for water t o run off, thus preventing the water from flowing over the edge of projections and down the face of the building. Edge and drip strips are also in
st alled in wood frame construction at gable ends ( (3) below), and projections such as window head cornices, water tables, and moldings ((6) below) . Gravel stops ((2) below) for built-up roofs with gravel surface, serve also as edge and drip strips. F or such roofs of smooth surface the shape of strips is lightly modified, however installation is about t he 
same. 
AGO 8488A 
SET SHEETS BACK OF $WtNG>U! •UTTS SHEETS 2" ABOVE !>NJIII~£$ 
a 
----1 
EXTENSION MAY 
c 
i 'Oj 
I LAP+EXP.+I" · 
f 
J 
FLASHING WITHOUT FLAPS 
~AP 
A 

EXPOSURE 
>· 
SECTION "A · A" ALTERNATE FLASHING SHEET WITH FLAPS 
figure 34 . Closed valley flashings . 
AGO 8488A 
EDGE OFS HI NGL ES 
SADDLE MADE IN ONE PIECE 
DETAIL OF SADDLE
OR CRICKET
STEPPED CAP FLASHING 
CAP ANDIIASE ONE PI ECE 
ALTE RNAT E 
BASE
FLASH IN G 

CONTINUOUS CAP'
FLASHING AT BASE 

Figure S5 . Typical details of chimney flashings. 
(2) Gnwel stops (fig. 38). Built-up roofs eaves, turned back and mopped with covered with slag or gravel require hot bitumin over the succeeding layers gravel stops at the edge of the roof and of roofing felt a distance of 10 inches. around drains to prevent the slag or The inner flange of the gravel stop is gravel from being washed into gutters extended onto the roof not less than 4 and drains. In some cases the top edge inches, embedded in plastic cement and of the gravel stop is formed 2% to 3 secured with nails on 3 inch centers. The inner flange is then mopped wtih
inches above the level of the gravel to 
serve as a dam to retain water on the two layers of roofing felt 9 and 12 
roof; thereby reducing heat transfer inches wide. The outer edge of the 
through the roof. When gravel stops gravel stop is formed over the edge of 
the roof with the bottom forming a
are required around drains, they are formed as part of the drain flashing drip strip secured by an edge strip (par. 38) . Before installing gravel (par. 33h(l)) . Gravel stops are stops at eaves, the two bottom layers formed from sheets having a maxiof roofing felt are extended past the mum length of 8 feet with lapped and 
AGO 8488A
5& 
HOOO 
FLASHING 
FLASHING BUILT • UP SLEEVE JtOOI'IMG-· 
S~EEVE 
~-~/l 
FLASHING FOR FLAGPOLE
VENT PIPE FLASHING 
ON COPPER ROOF 

VENT PIPE WITH I CAP 	VENTILATOR ON RIDGE 
Figu1·e 36. Typical roof projection flashings. 
soldered joints. Gravel stops exceeding 30 to 48 feet in length are provided with loose lock (fig. 37) expansion joints. Materials for gravel stops are as listed in appendix II table 10. 

(3) 	Gable ends for shingled 1·oojs. Gable ends are flashed to prevent water from 
A GO 8488A 
being absorbed by t he exposed wood and eventually saturating the subsurfaces of the roof. Typical gableflashings are shown in figure 39. Flashings formed from 8-foot sheets with a drip edge are preferred ; however , when the gable end is subjected t o 


( 
L
SECTION A-A MASTIC 
LOOSE LOCK EXPANSION CAP 
Figure 37. Edge ,...-[ drip strips. 
Figure 3 8. Gravel st ops. 
severe driving rains, overlapping 
flashing integrated with the shingles 
offers better protection. 
(4) 	Changes of slope (shingled roofs). Changes of slope or shingled roofs produces a joint that usually cannot be protected by the shingles. Methods of flashing these joints are illustrated in figure 40. 
(5) 	Walls and parapets. Because of the large variety of walls and parapets projecting through, or adjacent to roofs, no set standards can be given for their flashing. Generally, the flashings used are combinations of cap, base, and through-wall flashings and can be treated as such. Typical installations commonly dealt with are illustrat ed in figure 41. 
(6) 	
Flashings for w ood frame construction. .Flashings are necessary at all places where projections or breaks in the siding occur. The flashings are constructed of copper or equal (table 10, app. II) and installed as shown in figure 42. 

(7) 	
Copings (figs. 41 and 43). Copings are installed over the top of walls to prevent the penetration of water into the wall. Copings are formed from copper or equal (table 10 app. II) in 8-foot lengths. Seams are locked and soldered with expansion joints (par. 31) placed at 30-to 48-foot intervals. The edges are formed over the sides of the wall into drip strips and secured with edge strips (fig. 37). 

(8) 	
R eglets. Reglets are used to secure sheet metal to masonry or concrete where water tight points are required. The reglet runs the full length of the joint to provide a continuous water tight seal. Reglets are installed before placing the concrete by nailing them to the wooden forms with double headed nails (of same material as, or 


AGO 8488A 
ROOF EDGING 
EDGE
EDGE NAILED
NAILED 

Figure 39. Gable end flashings. 
are cut flush with the concrete. Opentype reglets are filled with fiberboardor other suitable filler to preventcrushing or filling of the slot duringthe placing of the concrete. The formsare set and the concrete placed and allowed to flow around the reglet. Whenthe forms are removed, the reglet ispermanently set in the concrete. Theedge of the sheet metal being securedin the reglet is formed as detailed infigure 44 and inserted into the reglet.The sheet metal is secured by drivinglead plugs into the reglet on 12-inchcenters. Lead wool is often used topack the reglet but plugs are pre
FLASHING 
ferred. The remainder of the slot isfilled with calking compound. 
WOOD SCREW 
WITH 34. Roofing 

STRIP Four basic types of sheet metal roofs (TMS-617) are in common use and include fiatseam, standing seam, batten seam, and corrugated roofing. (TM S-617) Flat seam roofs al
FLASHING 
though adaptable to any roof are primarilyused on fiat decks and warped or curved surFigure 40. Change of slope flashings (shingled roofs). faces such as spires, domes and cupolas. Standing seams are the easiest to intall and offer goodof material compatible with, the regdurability but are limited to roofs having alets), and spaced on 12-inch centers. minimum slope of 3 inches per foot. BattenAfter removal of the wooden forms, seams are more difficult to install and are subthe nails projecting from the reglets ject to the same limitations as standing "earns 
AGO 8488A 
61 
. 
FLASHING 
BATTEN 
PENTHOUSE WALL 
HIGH PARAPET 
AT FLUE-CAP LOW PARAPET 
FOR PROMENADE DECK 
.
PARAPET LEAD WOOL 
FIREWALL 
LOW PARAPET 
Figure 41. Typical flashing s for walls and parapets. 
but offer better durability with ess mainteand staggered cross seams. Cross seams are nance. Corrugated roofing is generally inexfolded in the direction of flow. All seams are psnesive and temporary depending upon the flattened with a mallet and sweat soldered to metal used) and offers rapid installation and insure water tightness. Large roof areas rehigh strength without the use of solid decking. quire expansion joints every 30 to 48 feet. An 
a. Flat Seam Roofing. Small sheets, usually expansion batten ~ection is recommended bemeasuring 16 by 18 or 14 by 20 inches, are reccause of its water tight construction. Flange ommended. (See tables 9 and 10 of app. II for type expansion joints are not water tight and selection of material) . All edges are pretinned will leak if a drain becomes clogged and the and the corners clipped to permit folding, as dewater backs up to the top of the joint. tailed in figure 45. Opposite sides of the sheet b. Standing S eam Roofing. Standing seam are folded in opposite directions to permit lockroofing is constructed from sheets not larger ing with adjacent sheets. The sheets are secured than 20 inches by 96 inches (See tables 9 and 
with three cleats (par. 30c) two on the long side 10 of app. II for selection of material). The and one on the short side. The other two sides standing seam should finish not less than 1 inch are locked to adjacent sheets already cleated. high. The development of the standing seam is The roof is laid with straight longitudinal seams detailed in paragraph 30a. The spacing between 
AGO 8488A
62 
SHINGLES-+ 
EDGE STRIP 
EDGE STRIP 
1 Casing flashing (drip cap and moulding) 
2 Dormer si ll flashing 
3 Window head cornice (shingles) 
4 Window head cornice (stucco) 

5 Casement window sill 6 Door si ll (above canvas deck) 7 Water table 8 Termite shield 
Figure 42. Typical flashing s for wood frame con s truction. 
SOLDERED SEAM 
COPING 
OVER MORTAR 
Figu1·e 43 . Copings. 
AGO 188A 
the seams varies with the width of the sheet and the height of the seam. In no case should the distance between seams be greater than 16% inches. Standing seams are not soldered to permit lateral movement and eliminate the necessity for expansion joints. Cross seams are staggered and locked but not necessarily soldered unless the conditions dictate otherwise. Standing seams can be used on roofs having a minimum slope of 3 inches per foot. Figure 46 details the installation of a standing seam roof . 
c. Batten S earn Roofing. Battens are square or rectangular strips of wood such as cypress, spruce, or pine, (cypress preferred), with the lovver edges beveled to permit free lateral movement of the metal roofin g. The battens must be 

WOOD 

... 
... 
... 
. \ ... 
.." ..::.:\ . 
FORM 
HEAD NAIL 
"'-REGLET IN CONCRETE 
FLASHING INSTALLATION 

FLASHING 
:PREFORMED REGLET AND FLASHING NOTE~ NAILS SHOULD BE NONFERROUS AND 
Figure 44. 
smooth, have all nails set, and be treated (Fed. Spec. TT-W-571) to resist rot and insects before the roof is laid. The battens are generally spaced between 20 and 30 inches apart with the exact spacing being adjusted to fit t he width of the sheet. Sixteen-ounce copper or equal (table 10 app. II) is recommended when the width between battens is less than 20 inches, and 20ounce copper or equal for width over 20 inches. The development of the batten seam is detailed in paragraph 30a(l). Cleats (par. 30c) are spaced at 8 to 10 inch intervals along the batten and at the center of each cross seam be-
COMPATIBLE WITH METAL REGLET 
Reglet details. 
tween the batten. The batten pans are installed between the battens with sufficient allowance between the beveled portion of the batten and the seam to provide for expansion and contraction. The cross seams are locked but not soldered. On roofs having a slope of 3 to 6 inches per foot, the cross seams are calked with white lead. Details of batten roof installations are illustrated in figure 47. 
d. Corrugated Roofing and Sidi ng. Corrugated roofing material is generally made of galvanized iron. However, for more durable construction, corrugated aluminum, stainless steel 
AGO 8488A 
EXPANSION BATTEN SECTION "B·B" 
8 ...---,... -.-, 
-,
·r....I -~ ------~
-------1 
1!'--\ ; · [ -1 ~
l
A 1 CLEATS . __... .J A i5 
jil6" ~
t 1. --.J §
I 	~ I I 
J~-j---------' 	0 I -~N_E-0~ ~~L~J --I 1 L _J 
-~--..1
18" 
INTERSECTION SECTION A·A 	TYPICAL SHEET 
Figure 45. Flat seam t·oofing. 
and copper are also available. The pitch of corlowed to overhang the eaves 2 inches. The rugat ions varies for different metals, the most sheets are secured with nails and lead or neocommon being 114 inches and 21!2 inches wide pr ent washers driven through the highest point measuring from peak to peak. The 2%-inch of every fourth corrugation. The longitudinal corrugation is the most widely used. All comspacing of nails is usually 24 inches but varies ponents for corrugated roofing and siding are depending upon the spacing of nailing slats. fabricated at the factory for ease of installation. Solid roof sheathing should be covered with one All components must be of the same size corrulayer of asphalt-saturated felt prior to instal1gation and the same material. Laying of the ing corrugated sheets. Additional rigidity may corrugated roofing sheets is begun at the lo¥rest be obtained by staggering the ends of sheets. corner away from the prevailing winds to preRidge caps and methods of flashing corrugated vent rain from driving under the lapper edges. roofing are illustrated in figure 48. Rubber end The order of laying is shown in figure 48. The seals are utilized to provide water-tight joints side lap is 1% corrugations (one corrugation at eaves, ridges, and flashings as required. for siding) and the overlap at the ends of the Various good methods of treating external and sheet is at least 6 inches ( 4 in. for siding) . The internal corner joints of corrugated siding are sheets are set flush with the gable ends and al-in use. Manufacturers' recommendations for 
AGO 8488A 
'/2." FLAT 
RIDGE DETAILS 
SECTION A-A 
TYPICAL BAY-STANDING SEAM METHOD 
"A " 
STEP I 
STEP 2 
STEP 3 SHEETS PANNED AT CORNERS RIDGE 
I 
~::=::=s===:==:::::::I::::=7STANDING ·SEAM 
PEAK OF HIP 
I 
Figure 46. Standing seam roofing. 
66 AGO 8488A 
COMPLE TE D 
INTERSECTION 
AT RIDGE 
PORTION Of BATTEN SEAM ROOf 
}2•CAP-LOCK ( USED FOR BOTH LOW 
AND STEEP PITCfl ROOFS) 
LOW PITCH (3"TO 6" PER FOOT ) 
Figure 47. Batten seam 1·oojing. 
these should normally be followed. This roofing should not be installed on roof slopes lower than 3 inches to the foot . 
35. Gutters 
Gutters are placed a t the edges of sloping roofs to catch the water draining off the roofs and carry it to downspouts. Hanging and builtin gutters are the two common types of gutters. Hang in g gutters are exposed and suppored at the eaves with hangers. Built-in gutters (gutter linings) are installed in cornices or where a verti cal wall projects past the eaves of a sloping roof. See tabl e 10, app. II for gutter material. 
a. GutteT sizes. Gutter size is computed from the leader size (par. 36cd. When the leaders are placed at 20-foot intervals, the gutter width is equal t o that of the leader. F or each addit ional 30 feet of gutter (or fraction thereof) between the leaders, the gutter width is increased 1 inch. Gutters less than 4 inches wide are not recommended in any case. 
b. 
GutteT Slope. Guters must slope in the direction of the leader with a minimum drop of 1 ) 1; inch per foot of length. 

c. 
Expansion J oints. Provision must be made for expansion and contraction in all gutters. Most hanging gutters are installed with slip or un soldered lap joints at 30-to 48-foot intervals. Built-in gutters over 30 feet long are constructed in 30-f oot sections joined together with expansion j oints. Gutter ends should never abutt a vertical wall. A minimum clearance of one-half inch should be left between the end of the gutter and the wall. 


AGO 8488 A 

RIDGE 

.F LAT 
ALTERNATE WALL BASE FL ASHING 
FINISH 
NOTE : PROVIDE A LIB E RA L CA LK ING BEAD BETWEEN EACH END AND SIDE LA P OF SHEETS AND ACCESSORIES 
Figure 1,.8. Corrugated ?·oofing . 
d. Hanging Gutte1·s. Hanging gutters are outer edge 1 inch lower than the inside edge to supported at the eaves with hangers or straps allow the water to spill away from the building (2, fig. 49) spaced not more than 30 inches in the event a leader becomes stopped up . apart. Other types of hangers are illustrated e. Built-In Gutter (Gutt er Linings). Gutin figure 50. A variety of gutter shapes are ter linings are constructed to fit the shape of available for decorative purposes; however, the the cornice or bed provided for it (fig. 51). The half-round and molded box gutters are used in inne1· edge extends up the roof or wall to a level 
practically all installations. Gutters are in5 inches above the outer edge and is either sestalled with a minimum slope of VJ. 6 inch per cured under a metal roof, extended 4 inches foot in the direction of the leader and with the into a composition roof, or protected under a 
AGO 8488A 
1 Gutter 7 Gutter end 
2 Hanger strap 8 Leader head 
3 Strainer 9 Leader strap
4 Outlet 10 Leader (downspout)
5 Bird screen 11 Leader shoe 
6 Elbow (goose neck) 12 Leaf screen 
Figure 49. Roof d1·ainage components. 
cap flashing. The outer edge is lower to permit overflowing in the event of a clogged drain and is therefore usually formed over the side of the cornice or wall and formed into a drip strip sP.cured by an edge strip. The outlet detail for built-in gutters is deta iled in figure 51. 
f. 
Hanging Gutter Outlets. The gutter outlet is shaped similar to a funnel to prevent the water from flowing over the outlet. The outlet opening of the gutter should be as long as the gutter is wide and two-thirds as wide as the gutter. The depth of the outlet is 11/2 to 2 times the leader diameter with a continuous taper ending in an opening equal in size to the leader. A strainer basket of material compatible with gutter is set loosely in the outlet to prevent debris from clogging the leader. Strainers set in ferrous-metal-gutter openings must be completely coated with asphaltum paint (Fed Spec. SS-A-701). Strainers used with aluminum gutters should be made from 0.06inch aluminum w1re. 

g. 
Leaf Screens. Leaf screens (fig. 49) are one-half-inch mesh wire screens fabricated from materials compatible with gutters. Screens are a vailable in various-length removable sections, and are used to prevent the clogging of 


AGO 8488A 
outlets and downspouts in wooded areas where leaves are a problem. 
36 . Leaders (Downspouts) 
Leaders (or downspouts) are placed at intervals in the gutter to carry the water from the gutter outlet to t he ground level. Leader components are illustrated in figures 49 and 52 and include elbows or goosenecks to move the flow of water from the eaves to the side of the structure; leader heads to prevent vacuums in long runs (40 ft or more) ; leader pipes to carry water to the ground level; hooks or straps to secure the leader to the structure; and leader shoes to deflect or divert the vertical flow away from the building. 
a. Leader S ize. Leader size is computed from 
the intensity of the rainfall in the area and the area of the roof being drained. Table 6 gives the roof area drained by 1 square inch of leader for various storm intensities. The intensity of storms is measured in inches per hour and is computed from storms lasting 5 minutes. Storm information can be obtained for any locality from the U.S. Department of Commerce. This information is compiled in chart form and gives the storm intensities which may be exceeded one in 5 years, once in 10 years, and maximum recorded storms. When computing the leader size, consideration must be given to whether or not the gutter can overflow periodically without damaging the structure. The leader size is computed by finding the actual roof area drained per square inch of leader for the expected storm intensity (table 6) and dividing it into the roof area to be drained. The answer will be the required cross sectional area in square inches of the leader required. 
Table 6. Sizing of Leader s 
Sq ua r e feet of actua l roofInten s ity of sot rm lasting 5 
drained through 1 s quare in c h 
minutes (in in. p er hr.) 
of leade r 
1 850 2 600 3 400 4 300 5 240 6 200 7 175 8 150 9 130 10 120 11 110 

...... 
<'~
~»--, ~ I 
?<tl ~ I 
SINGLE BEAD SINGLE BEAD DOUBLE BEAD SLIP JOINT 
HALF-ROUND 
,,,
\ \.\\\. \ 
..,.....,,,,,,,
",..s~''"' 
"' 
MOLDED GUTTERS 
OUTLET STRAINER 
> 
Cl 
0 
~ 
00 00 
> 
STRAP HANGERS 
GUTTERS 
ADJUSTABLE HANGERS 
\(JO 
OUTLET, ASSEMBLY AND END CAP 
SPIKE AND FEitRULE INSTALLATION 
F igu1·e 50. H anging gutter components. 
SOLDERED LOCK SEAMS 
DIAGRAM OF GUTTER LINING 

GUTTER LINING IN STONE CORNICE 
Figure 51. 
b. 
Spacing of Leaders. Leaders should be placed at corners wherever possible to avoid the necessity of water flowing around sharp bends. The maximum spacing of leaders is 75 feet. 

c. 
Goose Necks. Goose necks are formed between the gutter outlet and leader head to move the flow of water from the gutter to the side of the building. The goose neck is factory preformed or made up of two elbows joined to form a smooth flowing 5-curve. The goose neck should be the same size as the leader with all joints soldered. 


d. L eader Heads. Leader heads are placed 
at 40-foot intervals to eliminate the vacuum created by water falling down the leader. In long runs, this vacuum can collapse the leader or draw air into the leader; thus reducing the efficiency of the draining system. The general installation of leader heads is shown in figure 
AGO 8488A 
BRAZED 
2 
W=3GUTTER WIDTH 
f------W 

OUTLET 
DETAIL 

OUTLET TUBE 

Gutter linings. 
49. There is no solid connection between the 
leader head and the upper section of the leader; therefore, the problem of expansion and contraction is eliminated in long runs. ~ote the use of bird screens (5, fig. 49) to prevent the entrance of birds, squirrels, and debris. 
e. L eaders. Leaders are constructed of 16ounce copper or equal (table 10, app. II) in the styles shown in figure 52. The corrugated leaders offer better resistance to freezing, thawing, and collapsing. Leaders are set plumb and clear of the wall by hooks (fig. 52) or 2-inch wide strips (fig. 49) soldered to the leader and secured to the supporting structure. Hooks or straps should be placed at the top and bottom of the leader, at each floor level, and at intermediate points as required. Material for straps should be compatible with the leader and at 
least three times as thick as the lead3r material. The hooks and straps should not be 



tightened against the leader to the extent that the leader is dented or deformed since they are intended to hold the leader to the building and offer little or no vertical ~upport. Leaders are generally supplied in 10-foot lengths and are installed with lapped and soldered seams. Slip joints should be provided at 20-foot intervals for expansion and contraction. 
f. L eader Sho es. Leader shoes are placed at the bottom of the leader to project the water in a horizontal direction away from the building. Since the falling water and debris have an errosive effect that is accelerated by the deflection angle, the shoes are us ually reinforced at the outlet or cast of harder materials (i.e. brass or bronze for copper lead~rs ; cast iron for ferrous leaders). 
37. Splash Pa ns and Splash Blocks 
Splash pans are installed under all downspouts discharging onto composition roofs to prevent errosion of the roof and splattering of the walls in the area of the downspout. Splash pans are constructed not less than 18 inches 
I • I 
P L A IN CORRUGA TED P L A I N C OR R UGATED 
RO U ND R E C T A NGUL A R 
LEADER PIPES 
Y11 
LEADER HOOKS 
LEADER SHOES 
Figure 52. L eader accessories. 
wide and 24 inches long, of material compatible with the gutters (table 10, app. II) with undercut saw-tooth ribs or other suitable deformation along the bottom of the pan. The sides and one end of the pan are formed with baffles not less than 1 inch high and doubled over to form continuous horizontal flanges not less than 3 inches wide which are stripped into the top layer of roofing composition and mopped with hot bitumen before the slag or gravel top covering is placed. The rear flange of the pan is formed 8 inches high to extend under the side wall covering or cap flashing. Splash blocks are required to divert drainage discharge away from building at ground level where downspouts are not connected to storm drains. Blocks are constructed of concrete and are about the same size as splash pans. Such block are available where precast concrete products are sold, or may be precast at jobsite. 
38. Scuppers and Roof Drains 
Scuppers are emergency overflow drains leading from built-in gutters (par. 35 e) or roof drains to the outside wall of a building to relieve the excess water in case of drain or gutter failure. Scuppers should be made of 20-ounce copper or equal (table 10, app. II), have a minimum opening of 12 square inches, and be installed not more than 2 inches above the level of the roof drain. The inside edges of the scupper must be of sufficient length to permit lapping and soldering to the base flashing. The scupper lining is formed smaller than the opening to allow for expansion and contraction with the seams locked and ~oldered. The outside edge projects through the wall and is formed into a spout with the bottom edge folded into a drip edge. The inside of the scupper opening is coated with plastic cement before installing the lining to insure a water-tight seal. Roof drains are constructed of 20-to 48-ounce copper or cast bronze and flashed with 20-ounce copper. Heavy cast strainers should be provided for all drain openings. Gravel stops ~hould be formed where there is a possibility of water carrying gravel into the scu ppers or roof drains. Roofs using water as a cooling agent require a water dam around the roof drain, to retain the proper water level. Figure 53 illustrates typical scupper and roof drain installations. 
AGO 8488A 


SCUPPERSOLDERED TO BASE
GRAVEL STOP OR 
FLASHING
WATER DAhl 

COMPO ROOF 
·:.;·-: _ ....._ . 
. " 4 "·.. f). 
. •. 
OUTLET WITH SCUPPER 
DETAIL OF SCUPPER 
Figure 53. Scuppers and roof drains. 
39. 	Scuttles made straight and without buckles. The top ofScuttles are openings in roofs and are genthe lining is rounded to provide a smooth flowerally used to gain access to the roof from the of warm air into the room. The lining is atinside of the building. The sides and lid are tached with straps to provide freedom of moveusually made of wood and covered with sheet ment. Material recommended for recess liningsmetal. The side coverings are nailed to the is 26-gage galvanized iron. A typical cross secinside, formed over the top, and extended down tion of a radiator recess lining is shown in figthe outside of the scuttle where it is treated as ure 30. a base flashing {par. 33a). The lid should belarge enough to provide a 2-inch overhang on all 41. Snow Guardssides with a lip to insure proper seating. The 
Snow guards are placed on roofs to protect
sheet metal is laid across the top with the edges doorways, gutters, cornices, and other projecfolded under the apron and secured with nails 
tions below the eaves against snow sliding off
on 111 inch centers. The sheets are secured to roofs. Snow guards are formed from copper orthe top of the lid with cleats spaced on 12-inch copper alloy wire, nine gage or heavier withcenters folded into locked and soldered seams. loops approximately 2 inches high. Areas subjected to heavy snow falls require a heavy snow
40. Radiator Recess Linings 
guard constructed similarly to the pipe snowRadiator recess linings are installed around 
guard illu trated in figure 54. For new shingled
radiators that are set flush in the wall. The roofs, the leg of wire guards is formed to be
rece~s to be lined is fully insulated to prevent driven into the roof sheathing between the
heat loss through the wall. The lining is formed 
shingles with the loop projecting just below the
to provide a loose fit in the recess with all bends 
edge of the succeeding course. For old shingled 
AGO 8488 A 
73 
'---------------
roofs, the leg is formed into a hook which is slipped between the shingles and hooked over the top of the lower course of shingles. For sheet metal roofs, the legs are bent in opposite directions for stability and flattened to facilitate soldering. The guarde are placed at not more than 18-inch intervals both horizontally and vertkally with each course staggered. The snow guards extend from the eaves a distance of 31 ~ to 5 feet up the slope of the roof and not less than 5 feet each side of the area to be protected. 
42. Roof Ventilators (fig. 55) 
Roof venblators are prefabricated from 24ounce copper, 24-gage galvanized iron, or other material such as aluminum. The venblator is usually formed with a built-in base flashing and a sufficient length of body protruding below the base flashing to support the ventilator. The opening in the roof should be cut slightly larger than the ventilator body and the roofing surface should be stripped to accommodate the base flashing. The opening in the roof and the uncovered portion of the roof are coated with 
METAL ROOFS
NEW WORK OLD WORK 
TYPES OF WIRE GUARDS 
pla tic cement to provide a water tight seal around the ventilator. The ventilator is positioned in the roof opening and flashed with a sleeve and cap flashing similar to a stack or vent flashing (par. 33g) . The gable louver-type roof ventilator has been standardized to the point that it is more economical to purchase than to fabricate. It consists basically of a fame, stor'm slats, and insect screen, and is adjustable to various roof slopes. Gable (and wall) ventilators are also made in other shapes and are usually of aluminum, but are also made of copper, galvanized iron, or wood. 
43. Smoke Jacks and Breaching (figs. 56, 57, and 58) 
Smoke pipes projecting through temporary structures present a flashing problem because of the smoke jack and breaching. The smoke jack consists of a pipe 4 inches greater in diameter than the smoke pipe with a length sufficient to project a minimum distance of 9 inches above and below the roof or intermediate floors. The purpose of the smoke jack is to provide a flow of air between the two pipes, thus reducing the heat intensity around the pipe to protect the 
I INSTALLED WI R E GUARDS 
I 
INSTALLED PIPE GUARD 
Fi gure 54. Snow gua1·ds. 
AGO 8488 A 
ADJUSTAtiLE GABLE 
Figu1·e 55. Typical r oof v entilato1·s . 
""Urrounding wood frame construction. A linch airspace must be provided between the smoke pipe and roof flashing to vent the air flowing through the smoke jack. A drip cap is installed on the smoke pipe to prevent water running down the smoke pipe from entering the roof flashing through this air space. The major cause of leaks around smoke pipes is improper installation of drip caps. The outer edge of the drip cap must be at least 8 inches greater in diameter than the smoke pipe and installed 1 inch above the top of the roof flashing. The inner edge of the drip cap is sealed with stove putty or other heat resisting sealer and secured with a clamp or mechanical fasteners. The roof opening is formed to provide 4-to 9-inch minimum airspace between smoke jack and combustible materials as shown in (fig. 56, 57, a \ :1 58) for various types of smoke pipe materials and arrangements. Adjacent combustible materials are also lined with asbestos millboard as indicated. The roof flashing is formed so the base will completely cover the breached area 
AGO 8488A 
with a 4-inch flange extending onto the roof in all directions. The body tapers inward until the top of the flashing is secured with mechanical fasteners and spacers; the bottom flange is embedded in plastic cement and mopped with two layers of roofing felt. Modifications may be made to ventilated smoke jacks to eliminate the loss of heated room air by installing fresh air ducts as shown in B figure 56 . Insulating materials are used to reduce and eliminate the loss of warm air for coolin g purposes (figs. 57 and 58) . 
44. 	Air Movers 
Air movers are placed at the top of smoke stacks and ventilators to draw fumes and air up the pipes and ductwork. Two types of air movers are used. One operates by natural stack draft andj or wind currents, and the other by mechanical means. Mechanical type air movers are used only on large stacks and ventilators that require continuous or exceptional drawing qualities. 
45. 	Maintenance of Roofs and Flashing 
Routine maintenance inspections are conducted twice a year to check for physical damage and cleanliness of roofs, flashings, and gutters. Spring and fall are usually recommended as ideal times to conduct these inspections. 
a. 
Clecming . Roofs and gutters should be t horoughly cleaned of all foreign matter that will clog the gutters and drains. Strainers should be checked for conditions that would indicate the possibility of a clogged or partially clogged drain. 

b. 
Inspections. Inspections should be conducted by personnel who are experienced with sheet metal. Inspections should include the following: 

(1) 	
General appearance for evidence of physical damage, corrosion, and condition of paint or protective coatings. 

(2) 	
All flashings making a watertight connection with the roof (base flashings, sleeve flashings, and various wall flashings) for deficiencies that may develop into leaks. 

(3) 	
Seams and reglets for condition of calking compounds, tightness, and condition of solder. 





~----3 /16 X lf2"STOVE BOLTS 
24-GA BLACK-IRON CAP-----.._ 
~---THREE 24-GA SUPPORTS 
1; a" RIVETS 
C
24-GA BLACK-IRON SMOKE PIPE~-'+--f------r
•" -~3' -0" MIN ABOVE 
ROOF RIDGE
I/
DRIP CAP RIVETED TO 
PIPE. 1/8" RIVETS 4" OC AND SEALED WITH STOVE PUTTY  SIX 3/8" DIA X 1" PIPE USED AS SEPARATORS HELD WITH SIX 3/16'' STOVE BOLTS  
~~~v.-----1" AIR SPACE OPEN  
\.------24-GA BLACK-IRON FLASHING  

FOUR 12-GA WIRE HANGERS 
~---1/4" ASBESTOS MILLBOARD SHIELD CEILING FINISH TO EXTEND 1'-0" BEYOND ENDS OF SMOKE BOX 
SECTION THROUGH RIDGE WITH CEILING 
SIX 3/&''DIA X 2 " PIPE 1" AIR SPACE OPEN 
USED AS SEP
ARATORS HELD WITH SIX 3/16'' EXTEND 1/4" ASBESTOS STOVE BOLTS MILLBOARD 1'-0" BEYOND FRAMED OPENING 
LEGEND SYMBOL DIMENSION tiNCHESI 
A  6  7  8  9  10  12  
B  12  14  16  18  20  24  
c  4  5  s  6  6  7  SECTION WITHOUT CEILING~  

A-Details of ventilated smoke pipe utilizing cooling air from room 
Figure 56. Ventilated smoke pipe. 
AGO 8488A 
VENTED 
AIR SPACE 

EXISTING ROOF FLASHING 
FRESH AIR INTAKE 
WITH %" MESH 
BIRD 	SCREEN 
SECTION WITHOUT CEILINGS 
PLAN 
EXISTING CONSTRUCTION NEW CONSTRUCTION 
B-Details of vent ilated sm oke pipe modifications for utilizing external cooling air 
Figure 56-Continued. 
(4) 	
Cap flashings for distortions and pulling away from the base flashings. 

(5) 
Through-wall 	flashings and sheet metal imbedded in masonry for broken bonds between the sheet metal and 

masonry. 

(6) 	
Gutters for secure mounting, damage from erosion or corrosion and broken seams. 

(7) 	
Leaders and down spouts for evidence of stoppage, buckling around straps or 


AGO 8488A 
hooks, insecure fasteners, and broken or missing strainers. 
(8) 	All roof projections for condition of flashing and weatherproofing. 
c. R epairs . The first step with any repair job is to determine the cause of the damage. If improper design or installation is the cause, redesign or reinstallation may be required for correction. Damage caused by fair wear and tear can usually be repa ired by the sheet metal mechanic without difficulty, the extent of re
24-GA W EATHER CAP 
THREE 12-GA 
HIGH POINT
GUY WIRES ---.;' 
OF ROOF 
THREE EQUALLY SPACED s/8" SPACERS 
3/4" AIR SPACE 
__..---11 /2" INSULATION !LAMINATED ASBESTOS WITH 26-GA METAL JACKET) 
~====--12-GA STEEL WIRE STAYS 
l:i.l~------20-GA INSULATION RING WITH 3 /4" ANNULAR OPENING 

SECTION AT ROOF 11 /2" INSULATION 
(LAMINATED ASBESTOS 
WITH 26-GA 
METAL JACKET l 


rfl(~---i~~fl:;____11 /2" 1NSULAliON-CONTINUE THROUGH ROOF 
1/&" X 1 3/4" SCREW EYE 

-fl~--+----~ 20-GA INSULATION L--+-__; RING WITH 3/4" ANNULAR OPENING 
SECTION AT CEILING 
SCHEDULE  
SYMBOL A B c  6 12 4  7 14 5  DIMENSION 8 9 16 18 5 6  IINCHESI 10 20 6  12 24 7  14 28 9  16 32 10  

DETAIL OF INSULATED METAL SMOKE PIPE 
Figu?·e 57. Detail of insulated and ventilated smoke pipe. 
AGO 8488A 


THREE 16-GA SUPPORTS WELDED TO CAP----
SHEET-METAL SCREWS 
1 
z 
28-GA METAL JACKET----.jj 
i
·. 
q
2 " INSULATION 
;.,
(REFRACTORY CONCRETE TYPE) 
24-GA 	METAL COLLAR 
2" WIDE ------

14-GA 	METAL HOOD 
I 
METAL BEAD ROLLED TO ALLOW FOR 1" x 1" x Ve " METAL (OLLAR 
...
... 
ii 
> 
"' 
z i 
2" SLAB 2 ' -0" x 2 ' -0" SQ MIN 
3" x 3" 12-GA MESH REINfORCING 

FOUR 	18-GA 1V2" WIDE STRAPS 
6 " DIA SMOKE PIPE----olt 
Figure 58. Detail of insulated smoke pipe. 
placement and method of repair being left to 
the judgment of the sheet metal foreman. 

46. Ductwork 
Ductwork (fig. 59) is used to transfer air, gases, and fumes through structures. The most common uses of ductwork are in ventilating, air conditioning, and air-heating systems. The National Board of Fire Underwriters (NBFU) Pamphlet 91 covers requirements for special ductwork and should be complied with. Most of the components used in ductwork systems are factory made or formed in the s hop, leaving only the installation to be done on the job. Table 7 gives the recommended gages for sheet metal ducts, type of transverse joint connection, and the required bracing for various size ducts. 
a. Seams and Joints. The side seams are either double lock or Pittsburgh seams (par. 30a). Other ~earns can be used but these are the most universally accepted. The end con-
FigU?·e 59. Typical ductwork ins tallation. 
AGO 8488 A 

Table 7. Recommended Gages for Sheet Metal Duct Construction 
Rectangular Ducts • 
Aluminum Maximum
B. & S. Steel U.S. s id e, T ype of transverse join t connections h Bracing
standard gage
gage inches 
24 26 Up to 12 S-dr ive, pocket or bar slips, on 7-ft. 10-in. None centers . 13 to 24 S-dr ive, pocket or bar slips, on 7-ft. 10-in. None centers. 22 24 25 to 30 S-drive, l -in. pocket or l-in. bar slips, on 1-x 1-x 1h-in. angles 4 ft. from 7-ft. 10-in. centers.'' joint. 31 to 40 Drive, l-in. pocket or l-in. bar slip s, on 1-x 1-x lh -in. angles 4 ft. from 7-ft. 10-i n . centers! joint. 20 22 41 to 60 P h-in. angle connections, or P h -in. P h -x l lh -x lh -in. angles 4 ft pocket or P h-in bar slips with Us-in. from joint. x lh -in. bar reinforcing on 7-ft. 10-in. centers. 18 20 61 to 90 11h -in. angle connections, or 1 1h -in. llh-x P h -x lh -in. diagona pocket or l lh-in. bar slips 3 ft. 9-in. angles, or Ph -x Ph-x lh -in maximum centers with 1 % x lh -in. bar angles 2 ft. from joint. reinforcing. 2-in. angle connections or P h -in. pocket P h -x Ph -x Ys -in. diagona
16 18 91 and up or 1%-in, bar slips 3-ft. 9-in. maxiangles, or Ph -x l lh -x 1h-in mum centers with 1 % -x Ys -in. bar angles 2 ft. from joint. reinforcing.'' 
a For normal pressures a nd veloc ities utilized in typical ventil at in g and air conditioning system~. Where s pec ia l rigidity or stiffness All uninsul ated ducts 18-i n e h es and larger s hou ld be c ross-broken. 
is req ui red, ducts s hould be constructed of meta l two gages heavier. Cross-breaking may be omitted on uninsulated ducts if two gages of heavier metal are u sed . h Other joint connections of eq uivale nt mechanical s trength a nd air tightness may be u sed. 
in ch es with bracing a ngles omitted m ay be u ed ins t ead of 7-foot 10-inch lengths with joints indicated.
•· Duct sections of 3 feet !) 
d Ducts 91 inch es and la rger require special field study for han gi n g and supporting methods. 
Circular Ducts d . Damp ers. Dampers are installed to control the flow of air through the duct. The damper 
Aluminum \
B&S Steel U .S. Diameter of duct-inc h es is mounted on a shaft running through the duct
standard gage
gage with a control handle mounted on one end of the24 26 Up to 13 shaft. The control handle must be accessible,
22 24 Over 13 to 33% 20 22 Ov er 33Y2 to 67% have a locking device, and indicate the position of the damper. Fire dampers are installed in 
nections are usually formed to incorporate a ducts at junctions between rooms or sections of 
drive or bar slip seam (par. 30a(2). buildings as required by NBFU Standards Nos. 
b. Sealing of S eams and Joints. Normally the 90A and 90G. The fire damper is constructed seams and joints are adequate to prevent the of approved fireproof material such as steel leakage of air. In situations where the leakage plate, and attached to the inside of the duct of air or fumes would prove annoying or danwith hinges located at the top of the damper. gerous, the seams can be sealed with solder, Flexible wire 0r small metal chain with fusible mastic and calking compounds, and tapes. Tapes link is used to hold the fire damper in open position. A fire inside the duct or directly outside
are easily installed and are available in many sizes and types to suit most sealing requirethe fire damper will melt the link, permitting 
the fire damper to swing closed; thus prevent
ments. 
c. Hanging of Ducts. Ducts are usually susing the spread of fire through the duct. . pended from ceilings by steel rods fastened to e. Flexible Connections. Flexible connections are installed at the inlet and outlet connections
an angle iron bar for a cross brace under the 
duct. Size and spacing of these supports is of fans and other equipment that may cause vi

given in table 7. brations which can be carried through the duct
, AGO 8488A
80 
work. Flexible connections are made of heavy canvas, or if heat is a factor, asbestos or other fireproof cloth. The cloth is attached to the sheet metal as shown in figure 59 and the cloth is loose to absorb vibrations. 
f. Obstructions . Obstructions in ductwork should be avoided whenever possible; however, in some cases, pipes or similar obstructions must pass through a duct. When this occurs, the turbulence created by the object can be reduced by encasing it in a streamline collar as shown in figure 59. 
47. Shower Linings and Pans 
· Shower linings and pans because of their nature are subject to high water and moisture concentrations and severe abuse. From the hygenic point of view the shower must be easily cleaned and be able to withstand strong cleaning agents. 
a. Choice of Materials. Shower linings (fig. 60) are made of enameled black iron, galvanized iron, aluminum, and stainless steel. Enameled black iron is inexpensive and easy to install, but is readily attacked by corrosion when the enamel begins to wear off; it is therefore only recommended for temporary structures. Aluminum has good corrosion resi stance and sound deadening qualities, but is difficult to solder and waterproof. Stainless steel has excellent corrosion resistance, cleaning qualities, and is easily waterproofed; however, it is costly and is recommended for permanent structures only. Lead and copper possess excellent corrosion resistance, sound deadening and waterproofing qualities, and are recommended for shower pans and corner flashings. However, they should be covered with tile, concrete, or such, as their toxic nature renders them unsatisfactory for exposed shower linings. Shower linings should be made of 22-gage material, and shower pans of 6pound lead or 32-ounce copper. 
b. Installation. 

(1) 	Shower pans . The lead or copper sheet should be cut to allow pan to extend up all sides a minimum of 2 inches above step or curb. The corners are notched to permit the folding of the sides. After the pan is formed, the corners are brazed (burned if lead is used) to provide a watertight joint. The drain is located on the pan 
AGO 8488A 
and the proper size hole cut to receive the drain. If the pan is to be installed in cement-type material, the pan and cement are coated with asphaltum before installation. On wood, asphaltcoated building paper is placed between the pan and wood floor. The inside of the pan is coated with asphaltum before placing the drain the cement-type material. 
(2) 	ShoweT linings . Shower linings extend the full height of the shower and are secured on 16-inch centers at the top and sides of sheets with mechanical fasteners in such a way as to prevent leakage around the fastener. The bottom of the lining overlaps into the pan and is secured in the cement. Showers incorporating a concrete curb at the base of the show~r have the lining terminating on top of the concrete curb overlapping a metal skirt. The metal skirt is installed over the curb to protect the joint formed between the concrete curb and wall. Seams in the shower lining are locked and soldered. 


48. 	Range Hoods and Canop ies 
a. Range Hoods. Range hoods are placed over cooking ranges, ovens and similar equipment to reduce heat intensity and exhaust steam, odors, and fumes . For maximum effectiveness the hood should extend outward 6 inches past the sides and 12 inches past the front of the equipment, and be installed as close to the equipment as possible without interfering with the access t o or use of the equipment (min height is usually above the head level of personnel or 6 ft. 6 in.) . The minimum height of the hoods is 1% feet to trap steam or fumes. Material should be as given in table 10. All seams should be welded or brazed to provide a smooth, easily cleaned, airtight surface. The bottom edge of the hood should be folded under, forming a lip or trough to catch condensation and grease running down t he inside of the hood. The grease lip also serves as an edge stiffener (par. 30b). The opening in the top of the hood should be the same size as the attaching ductwork and accessible for cleaning (i.e. grease filter and air flow controls, if used, should be removable). 
8 1 

.• 
• ,0 '. 11 
:. · ~ .o . .... :." ~ : '\ --......_-_..-:-::-=-••.•• ;/~
..-_.-00· ... -_-_.:·._.(> .:·~ ·:· ~;-', ;~ 
~... · -0 .
SHOWER PAN (COATED BOTH CONCRETE FLDOR SIDES WITH 
AND CURB 
ASPHALTUM ) 

~ e::J

u 17 
SHOWER PAN 
Figure 60. Typical shower installations. 
The ductwork must be of sufficient size and equipped with a ventilating fan to provide a minimum air flow of 100 feet per minute over the horizontal face of the hood. (This air flow is called capture velocity.) Ceiling supports for hoods should be of steel rods or straps to afford a smooth surface for cleaning. Chains are difficult to clean and accumulated grease and dust which presents a health and fire hazard. 
b. Canopies . Canopies are protective coverings placed over equipment, doorways, windows , and similar areas as a protection against weather, dust, and falling objects. Canopies installed to protect machinery and shop equipment should be constructed of 26-to 23-gage galvanized or black iron. Canopies installed in kitchens usually are constructed of stainless steel, monel, or aluminum. Canopies installed on the outside of buildings should be constructed of a material compatible with the roofing and surrounding materials. Dimensions of canopies should permit a minimum overhang of 1 foot beyond all sides of the area to be protected . Bottom edges of canopies should be 
AGO 8488A 


formed into edge stiffeners (par. 30b) to provide Ridged edges for support. Seams for outside canopies should be locked and soldered to provide a waterproof surface. Seams for inside canopies may be welded, brazed, or joined with mechanical fasteners. 
49. 	Medical X-Ray Protection 
Medical X-ray protection for flouroscopic, radiographic, photofluorographic, dental, and other such rooms will be as required by TB MED 62. Hospital rooms and laboratories utilizing X-ray and other equipment that produce radiation dangerous to personnel require shielding to absorb or confine the radiation in the area of the equipment. Radiation is measured in roentgen; the maximum permissable dose is 
0.1 roentgen per week for occupational exposure, and 0.5 roentgen per year for nonoccupational exposure, both being whole body exposure. Radiation protection surveys should be performed for Army installations by organic health physicists of the installation, and by radiation protection specialists of the Army Environmental Hygiene Agency upon writt en request to The Surgeon General, Department of the Army, Washington, D.C., ATTN: MEDPSPO, to determine the placing of equipment and r equired shielding for personnel protection. When radiation protection surveys are impossible, the following installations will be adequate with a high margin of safety. 
a. 
Placing of Equipment. Radiation emitting equipment is shielded by the manufacturer to prevent radiation leakage. Placement should be in accordance with manufacturer's instructions and approved plans of the project as developed in line with the requirements of TBMED 62. 

b. 
Protection R equirements. Fluoroscopic, radiographic, photo-fluorographic, and dental X-ray rooms are subj ect to the following requirements. 


(1) 	Walls and floors having an occupied area within 50 feet of the outside surface thereof must have a density equal to 1ft6 inch of lead or be shielded with 1;1 6-inch lead. Table 8 gives the lead equivalents of concrete; and the weight per square foot of concrete wall. Figure 61 diagrams a typical X-ray room showing the location of shielding. 
AGO 8488A 
EXTERIOR 
0 
w 
0 
a.
Ill 
:J 
0. 	0 
u
:J 
0
u 
u 
0 
OCCUPIED 
PLACEMENT OF SHIELDING 
.. ..... ... . .... •''. 
0 ...... . 
............. ...... . 
... . . ........... 

• •• ••• 0 
•• • 	0 •• 
. . . . 	... . ·····.
. ... . .. .. 
0 0 •• 
.. .. 
... .. ... ·. 
. . . ..  .... .. .  .. .  ....  
: ..  
I ·''  
I' •  
INSTALLATION OF SHIELDING  

Figure 61 . Typical shielding for X-1·ay 1·ooms. 
Table 8. L ead Equivalents of Concrete for Shielding Against X-Rc!'ys 
Weight of 
concrete w a ll in lb/sq. ft. 
Vto-inch lead 5-in. thick concrete 65 1hz-inch lead 3-in. thick concrete = 40 0.5-mm lead 2-in. thick concrete = 27 
Note. Other building material such as bt·ick, solid cinder, or gypsum blocks may be substituted provided t he weight per square 
foot is at least eQua l to that indicated above and th e joints prov ide t he same attenuation as t he block or brick. 
(2) 	Operator shields. The X-ray control panel should be placed in a remote position away from the equipment but still in line of sight of the patient. A shield must be placed between the controls and the equipment to protect the operator. The shield must have a lead equivalent thickness of lf1 6 inch and be equipped with an observation 
window of the same equivalent thickfactory made lead-lined plywood 
ness. The observation window is losheets. 
cated so that the equipment and patient are in full view of the operator at all times. The shield is 7 feet high and arranged so that the radiation·is scattered twice before entering the control area. For dental X-ray work, a screen equal to %2 inch lead is placed behind the equipment to protect the operator. 
c. Installation PToceduTes. Lead sheets 1h6 inch thick should be used for covering walls and floors . A reduction in shee: thickness should not be made without the authorization of qualified personnel. The following rules must be followed to insure complete radiation shielding. 
(1) 	
Wall barriers must be at least 7 feet high. 

(2) 	
Lead must be mounted in such a manner that the weight of the sheet will not cause the lead to creep. One method of preventing this is to use 


(
3) 	Lead covered nails, screws, and other fasteners should be installed in such a manner as not to impair the overall protection. 

(4) 	
Seams and joints must overlap at least 1/ :! inch, or be welded or burned to provide an equivalent lead thickness at the joint, or be covered with a 3-inch lead strip and secured with two rows of nails spaced on 3-inch centers. 

(5) 	
Observation and protective windows must be constructed of a special glass to afford the same protection as the wall. Glass manufactured with a high lead content (lead glass) is generally used. Protective windows are overlapped by the wall shielding at least lh inch. 

(6) 	
Holes for pipes, conduits, and louvers should be provided with baffles to scatter the radiation in small quantities. 


84 	AGO 8488A 
APPENDIX I 
REFERENCES 

I. Department of the Army Technical Publications 
TB MED 62 Medical X-Ray Protection. 
TM 5-610 Maintenance and Repair-Buildings and Structures-Preventive Maintenance and Safety Requirements Repair and Utilities. TM 5-611 Repairs and Utilities; Post Engineer Shops. TM 5-612 Post Engineer Shop Equipment and Maintenance and Service-Equipment Inspections and Preventive Maintenance Services. 
TM 5-615 Concrete and Masonry, Repairs and Utilities. 
TM 5-616 Carpentry (when published) 
TM 5-617 Roofing; Repairs and Utilities. 
TM 5-618 Painting; Repairs and Utilities. 
TM 5-745 Heating, Ventilating, and Sheet Metal Work. 
TM 10-270 Repair of Quartermaster Items of General Equipment. 
TM 10-450 Sheet Metal Work-Body, Fender, and Radiator Repair. 

2. Military Specifications 
JAN-S-627 Solder, Low Melting Point. 
JAN-P-735 Zinc-Chromate Primer. 
MIL-A-928 Adhesive, Metal to Wood Structural. 
MIL-A-1154 Adhesive, for Attachment of Synthetic Rubber to Metal. 
MIL-A-8623 Adhesive, Epoxy Resin, Metal to Metal Structural Bonding. 
MIL-A-8625 Anodic Coatings, for Aluminum and Aluminum Alloys. 
MIL-A-14443 Adhesives ; Glass to Metal. 
MIL-A-45059 Adhesive for Bonding Chipboard to Terne Plate, Tinplate and Zincplate. 

MIL-B-7883 Brazing of Steels, Copper, Copper Alloys, and Nickel Alloys. 
MIL-C-1219 Cement, Iron and Steel. 
MIL-C-3316 Cement, Adhesive, for Thermal Insulation. 
MIL-C-3923 Calking Compound. 
MIL-C-11090 Cleaning Compound, Degreasing, Self Emulsifying. 
MIL-C-11794 Compound, Calking. 
MIL-C-14504 Coating, Pretreatment-! Package Wash Primer for Steel, Aluminum, and Magnesium. MIL-C-18969 Calking Compound (for Metal Seams). MIL-D-16791 Detergents, Nonionic. MIL-F-6939 Flux, Aluminum and Aluminum Alloy, Gas Welding. MIL-F-7516 Flux, Welding, Corrosion-and Heat-Resistant Alloys. MIL-F-14256 Flux, Soldering Liquid (Rosin Base). MIL-F-16136 Fluxes, Welding (For Copper-Base and Copper-Nickel Alloys and Cast 
Iron). 
AGO 8488A 


MIL-F-20138 MIL-F-20329 MIL-N-15178 MIL-P-6883 
MIL-R-1150 
MIL-S-6872 MIL-S-10104 MIL-S-12204 MIL-S-12875 MIL-T-704 MIL-W-6858 
MIL-W-8611 
3. Federal Specifications 
0-F-499 0-F-506 HH-C-581 HH-C-591 HH-F-191a 
&AM-2 QQ-A-359 QQ-B-613 QQ-B-00655 QQ-C-576 QQ-L-156 QQ-L-201 QQ-N-281 
QQ-S-551 QQ-S-561 QQ-S-571 
QQ-S-636 QQ-S-00640 QQ-S-682 QQ-S-763 QQ-S-766 QQ-S-775 QQ-T-201 QQ-Z-00100 RR-C-440 RR-S-141 SS-A-701 SS-C-153 SS-R-00451 SS-R-630 SS-S-159 Steel Corrosion-Resisting, Plate and Sheet, Floor, Rolled. 
Flux, Soldering, Noncorrosive. 
Naphtha, Solvent. 
Paint, Blended-Type, Coat-Tar-Pitch Base, Bituminous. 
Rivets, solid (Aluminum Alloy), and Aluminum Alloy. Rivet Wire and Rod. 
Soldering Process, General Specification for. 
Sheets, Metal, Coated. 
Solder, Aluminum Alloy. 
Sheets, Perforated Metal. 
Treatment and Painting of Material. 
Welding: Aluminum, Magnesium, Nonhardening Steels or Alloys, and Titanium, Spot, Seam, and Stitch. Welding, Metal Arc and Gas; Steels, and Corrosion and Heat-Resisting Alloys; Process for. 
Flux, Low Melting Point Silver Alloy Brazing. 
Flux, Soldering, Paste and Liquid. 
Cotton-Fabric, Woven, Asphalt-Saturat ed. 
Cotton-Fabric, Woven, Coal-Tar-Saturated. 
Felt; Asphalt-Saturated (for) Flashings, Roofings, and Waterproofing. 
Aluminum Alloy, Plate and Sheet 3003. 
Brass, Leaded and Nonleaded, Plate, Rolled Bar, Sheet, and Strip. Brazing Alloys. 
Copper Plates, Rolled Bars, Sheets and Strips. Lead Calking. 
Lead Sheet. 
Nickel-Copper Alloy (Monel and R-Monel) Bars, Plates. 
Rods, Sheets, Strip, Wire, Forgings, and Structural and Special Shaped Sections. Solder, Brazing. Solder, Silver. Solder; Lead Alloy, Tin-Lead Alloy, and Tin Alloy; Flux Cored Ribbon and Wire, and Solid Form. 
Steel; Carbon (Low-Carbon), Sheets and Strips. 
Steel, Carbon; Sheet and Strip. 
Steel, Corrosion Resisting-Clad Plates, Sheets, and Strips. 
Steel Bars, Shapes, and Forgings-Corrosion Resisting. 
Steel, Corrosion Resisting: Plates, Sheets, Strips and Structural Shapes. 
Steel, Sheets, Carbon, Zinc-Coated. 
Terne Plate for Roofing (Roofing Ternes). 
Zinc Alloy Sheets and Strips. 
Cloth, Wire, Industrial. 
Screening, Wire, Insect. 
Asphalt-Primer; (for) Roofing and Waterproofing. 
Cement; Bituminous, Plastic. 
Roof-Coating; Asphalt, Brushing Consistency. 
Roofing, Felt, Roll, Asphalt-Prepared, Mineral Surfaced. 
Sealing Compound, Cold Application Ready-Mixed, Liquafier Type, for Joints in Concrete. 
AGO 8488A 


TT-A-468 TT-C-598 TT-F-320 TT-P-31 TT-P-86 TT-P-641 TT-S-00227 
TT-T-801 TT-V-51 TT-V-119 TT-W-251 
TT-W-261 TT-W-571 UU-P-147 VV-K-211 VV-F-800 
Aluminum-Pigment, Powder and Paste for Paint. 
Compound, Calking; Plastic (For Masonry and Other Structures) . 
Filler, Crack and Seam (For Wood, Metal, or Concrete and Cement Mortar. 
Paint, Iron-Oxide, Ready-Mixed, Red and Brown. 
Paint, Red-Lead-Base, Ready-Mixed. 
Primer, Paint, Zinc Dust-Zinc Oxide (for Galvanized Surfaces) . 
Sealing Compound; Rubber Base, Two Component (For Calking, Sealing and Glazing in Building Construction). 
Turpentine, Gum Spirits. 
Varnish; Asphalt. 
Varnish, Spar Phenolic-Resin. 
White-Lead, Basic-Carbonate, Dry, Paste-in-Oil and Semipaste containing Volatile Thinner. White-Lead; Basic, Sulphate, Dry and Paste-in-Oil. Wood Preservative, Treating Practices. Paper, Building, Waterproofed. Kerosene. Fuel Oil, Diesel. 
AGO 488 A 
00 00  APPENDIX II  
SELECTION  OF MATERIALS  
(Tables 9, 10, and 11)  
Table 9.  Properties of Sheet Metal  
Mat~rial  Characteristics  P1·inciple u~es  Cost comparison copper == 100% (approximately)  Melting point  Coefficient of expansion (per degree F.)  Method of Joining  Precautions  
Copper  ______  High corrosion resistance. Excellent workability. T arnishes easily hnt P.VP.ntnally forms decorative coating called patina. Excellent heat and  Roofing. Gutters. Downspouts. F I ash i n g. Lab o rat o ry table tops, and sinks. Louvers. Scuttles. Drains. Shower pans. Should not be used where  100%  1980°F.  0.0000093  Use caution when welding. Excellent for a ll other methods.  Water which has been in contact with cop per will stain mason ry and painted sur faces, and corrode most other metals.  
electrical  conductor.  food  is  h a n d I e d.  
Aluminum  ___  Toxic. Good corrosion resistance. Light weight. Excellent heat and electrical conductor. Nontoxic. Good work Roofing. Sid ing. Trim. Flashing. Ductwork. Hoods. C a n o p i e s. Kitchen equipment.  50o/r  1218°F .  0.0000128  Welding requires shield of inert gas. Soldering not recommended. Brazing mechanical fasteners and seams  Not recommended for extensive seaming H i g h I y subject to electrolytic corrosion  
a b i I i t y.  E as i I y  recommended.  
Galvanized iron. Black iron____  cleaned. Fair corrosion resistance. Good workability. Nontoxic. Good fire resistance. Poor corrosion resistance. Good workability-Excellent resistance to a b r a s i o n.  Roofing. Siding. Gutters. Downspouts. Ductwork. Hood s. Wall linings. Canopi es. Fire doors. Ventilators. Floor plates. S t a i r treads. Roof decking. Wall I i n i n g s for stairways and eleva 15% 10%  Coating 786°F. Base (sheet 2700 °F. 2700 °F.  0.0000065 0.0000065  Excellent for soldering, seaming and mechanical fasteners. Welding and brazing destroy g a I v a n i z e cl surface. Excellent for al l methods of joining and seaming.  Protect i v e coating (Zinc) highly subject to electrolytic corro sion. High tempera tures destroy surface Easily damaged by a! corrosive elements.  
> C) 0 ~ co >  Stainless  steel  High strength. High corrosion resistance. Good workability. Nontox i c. Easily cleaned. Workhardens rapidly.  tors. Flashing. Decorative trim. Food handling equipment table tops, trays, s i n k s, and utensil s). Wall li nings.  133%  2560 °F.  0.0000058 to 0.0000096  R e q u ires additional power for seaming. Inert gas shield not required for welding but recommended to prevent surface clamage.  Extra power required for cutting and form ing operations. Sur face can be con taminated by i ron particles, c a u s i n g rust.  

> C'l 0 ~ 00 00 >  Monel  _______  Excellent corrosion resistance. Good workability. Nontoxic. Easily stained. Difficult to clean.  
Brass  _______  I High corrosive resistance. Poor workability. High strength and abrasive resistance. Brittle. Nontoxic.  
Lead  ________  I High corrosion resistance. Soft Plastic. S u b j e c t to creep. High density.  
Zinc· _________  I Good atmosphere corrosion resistance. High!y subject to electrolytic corrosion. Poor workability. Nont ox i c. Subject to creep.  

Roofing and drainage components (in highly corrosive atmosphere and salt water areas). Kitchen and food handling equipment. Laundry equipment. Decorative and protective items (door knobs, push plates, trim). Used with copper for support or abrasion resistance (screws, edge strips, brackets, straps, cast items). 
Shower pans. X-ray and radiation shielding. Sound proofing. Vibration dampeners. Acid and chemical containers. 
Nontoxic replacement for lead. Linings for refrigerators. Coverings for drain boards, sinks, and kitchen equipment. 
136% 2370°F. 0.0000077 
108%  1840°F.  0.0000104  
50%  618•F.  0.0000162  
53%  786 °F.  0.0000173  

Excellent for all methods. Solder offers no strength. 
Excellent for soldering, brazing, and mechanical fasteners. Seams have t e n d en c y to s pI it Welding not recommended. 
Soldering, seaming, and "lead burning" recommended. Mechanical fasteners should only be used in special cases. 
Soldering and mechanical fasteners recommended. Seams have tendency to s p I i t. Welding and high heat destroy metallic zinc. 
Surface tarnishes easily and is difficult to clean. 
Subject to fracture and split when stressed. If unprotected will tarnish easily. 
Subject to creep and fracture if unsupported. 
Subject to creep and fracture if unsupported. Splits easily, especially in co I d weather. 
(X) 
-o 
Table 10. Use and Recommended Thickness of Sheet Metals 
Copper Galvanized Corrosion-
Brass Aluminum Monel Terne 
(wt. per steel 3 resisting steel
(inches) (inches) (inches) (U.S. Std.)
sq. ft. ) (U.S. Std.) (U.S. Std.) 
Cornices and belt courses_______ 20 oz 24 gage 0.032 0.021 26 gage 24 ga ge Coping 20 oz 24 gage 0.032 0.021 26 gage 24 gage Corrugated siding 26 gage 0.032 26 gage 26 g age Ductwork Table 7 Table 7 0.021 26 gage 26 gage 
Drip strip ---------------------20 oz ------------------0.032 0. 021 24 gage Edge strip 48 oz 14 gage 0.083 14 gage F lashing: General 16 oz 24 gage 0.025 0.032 0.021 26 gage 24 gage 
Closed valley 16 oz 26 gage 0.032 0.025 26 gage 26 gage Spandrel beam 6 oz 1 32 gage Smoke pipes and vents______ 24 gage 
Through-wall 16 oz 0.018 26 gage Gravel stops 16 oz 24 gage 0.02 5 0.032 0.018 26 gage 24 gage Gutter linings 20 oz 24 gage 0.021 26 gage 24 gage Gutters (attached) 20 oz 26 gage 0.025 0.032 0.021 26 gage 26 gage Gutters (hanging) 16 oz 26 gage 0.025 0.032 O.D18 26 gage 26 gage 
Hoods and canopies_____________ 20 oz 26 gage 0.032 0.021 26 gage 26 gage 
Leaders (downspouts) 16 oz 26 gage 0.025 0.024 0.018 28 gage 26 gage Radiator recess linings__________ 26 gage 26 gage Roof ventilators 24 oz 24 gage 0.040 0.025 26 gage 24 gage 
Roofing: Corrugated 22 gage 0.032 24 gage 22 gage Batten seam ---------------16 oz ------------------0.032 0.018 26 gage 26 gage Flat seam -----------------20 oz ---------------------------0.021 24 gage 24 gage Standing seam -------------16 oz ---------0.032 0.018 26 gage 26 gage 
Scuttles -----------------------16 oz -----------------· 0.032 0.018 26 gage Shower pans 32 oz ' Splash pans 20 oz 0.025 0.040 0.021 24 gage 
Note. The above thicknesses are the minimnm to be used with the wo1·k indicated . Heavie r gages s hould be used when called for by 
the work or when conditions indicate that the minimum thickness will be unsatisfact01·y. 
1Requi res coating of plastic bituminous compounds (par. 33d). 
'Six pound lead may be substituted for 32 oz. copper. 
:: Galvanized steel and iron-for use principally on temporary a nd semipermanent work. 
Table 11. Comparative W eights of Roofing Materials 
Approximate installed weight.
Materia l lb for !OOsf 
Al uminum, 0.019 to 0.032--------------------------------------------------------33 to 60 60 to 75
Terne Plate --------------------------------------------------------------------
Corrugated or r ibbed galvanized sheets, 20 to 26 gage_____________________________ 215 to 120 Zinc sheets, 20 gage_____________________________________________________________ 
125 Copper sheets, 16 to 10 oz _____ _________________________ ________________________ 
130 to 80 Lead sheets, 0.125 thick__________________________________________________________ 
750 250
VVood shingles ------------------------------------------------------------------
Cement asbestos shingles__ ______________________________________________________ 275 to 600 500 to 1,000
Slate -------------------------------------------------------------------------
850
Tiles, Spanish -----------------------------------------------------------------
130 to 325
Asphalt shingles ---------------------------------------------------------------
Asphalt roll roofing_____________________________________________________________ 
35 to 80 "Built up" roofing (saturated felt, bitumen, slag, or graveL_______________________ 400 to 675 
AGO 8488A 
GLOSSARY 

Building papeT-A tough, tar-or asphalt-saturated or unsaturated paper. The term is used when referring to any kind of paper used in building construction. Further qualifications normally are required. In sheetmetal work coal tar or asphalt-saturated felt (or simply "felt") will satisfy most all needs such as sheathing paper, protective coverings, and insulating strips. 
Cant st?·ip-Strip of wood or metal used to elevate or change the slope of a row of shingles. Commonly used at the eaves to keep the first row of shingles elevated from gutters and flashings. Also a triangular piece of wood placed to provide a transition in angle of intersection of roof with a vertical surface. 
Chill bars-Various shaped pieces of conductive metal which are placed around the area where metal is being joined by welding, brazing, and such to absorb and lessen the spreading of heat from the area. This reduces distortion to articles being joined. Sometimes these bars serve in addition as jigs, supports, or holddowns. 
Co1·nice-Decorative projection placed near or at the top of building walls. 
Co?·Tosion-The decomposition of a metal when subjected to air, water, acids and similar solutions. 
C1·eep-The slow flow of a metal when subjected to sustained stress at elevated temperatures. Lead and zinc creep at normal temperatures while most metals must be elevated to high temperatures before appreciable flow occurs. 
Density-Weight of material per unit volume. Do1l'nspout-(Leader) A pipe constructed of sheet metal or other material used to carry water from gutters to ground level. DTip Edge-Formed edge of metal projected beyond the finished edge of a roof or projec-
AGO 8488A 
tion to discharge water without runback on walls or other surfaces. Ductility-The property of being able to withstand bending and drawing without fracture. Ducts-Round or rectangular sheet metal pipes used to transfer air and gases. Eaves-Projecting lower edges of roofs usually overhanging a wall. 
Elasticity-The property of a material to assume its original shape after a load or stress has been removed. 
Expansion joint-A movable joint that absorbs the movement caused by thermal or other expansion and contraction. 
Fatigue-Weakening or rupturing of metal caused by repeated stressing. 
Flash·ing-Sheet metal (or other suitable material) used in roof and wall construction to waterproof joints and critical areas. 
GutteT-A channel or trough used to catch water draining from roofs and carry it to leaders or downspouts. 
HaTdness-Ability to resist indentation. Malleability-Capable of being rolled or ham
mered without rupturing. Mastic-Flexible adhesive Plasticity-Ability to retain a deformed shape Po1·ous-Containing minute holes or separa
tions permitting the penetration of liquids, air, or gases. 
Saddle or· C?"icket-lnverted V-shape flashing used to cover the pocket formed between the downhill slope of a roof and a chimney, rectangular vent stack, or wall. 
Stmin-Deformation or distortion of materials due to stress or force. 
StTess-Intensity of internal forces resisting a change in the form of a body. 


T em.pe1·-The state of a metal or other subThe1·mal movem ent-Expansion and contrac
stance, especially as to its hardness or toughtion of materials caused by changes in temness. Temper in steel is either indicated by 
perature.
its carbon content or its color in tempering. 
It is designated either by a "Brinell" or a Toughness-Resistance to impact or permanent 

"Rockwell" set of numbers. deformation without fracturing. 

AGO 8488A 
INDEX 

Paragraph 
General lla,22a 
Adhesives  23c  
Air  movers  44  
Alloys:  

Nickel-copper (monel)----------14 Nickel-chrome-steel (CRS) ______ 20 Zinc-copper (brass) ____________ 15 
Aluminum (general) ---------------13 
Bar seams ------------------------30a Base flashing ----------------------33a Base metals -----------------------11a Batten seam roofing________________ 34c 
Beam flashing (spandrel)-----------33d Belt courses -----------------------32b Brass (general) -------------------15 Brazing --------------------------27 Breaching ------------------------43 
Built-in gutter linings______________ 35e Butt joints ------------------------29a 
Calking compounds ----------------23 Canopies --------------------------48 Cap flashing -----------------------33a 
Asbestos-cement materials __________ 22c Change of slope (flashing)----------33h (4) Chimney flashings -----------------33/ Clad-metals -----------------------22d 
Cleats ____________________________ 25d,30c 
Copings ---------------------------33h (7) 
Copper (general) ------------------12 Copper sheets, thickness of (table 4) _ Coppers, soldering -----------------26 Corner joints ----------------------29d Cornices --------------------------32a 
Corrosion resisting (stainless) steeL_ 20 Corrugated roofing -----------------34d 
Dampers (ductwork) --------------46d Downspouts (leaders) --------------36 Drain (roof) ----------------------38 Drip strips------------------------33h(l) 
Ductwork ------------------------46 
Edge stiffeners --------------------30b Edge strips -----------------------33h (1) Electro-chemical series (table 3) _____ 
Electrolysis -----------------------11e Equipment, sheet metal work________ 76 Expansion and contraction (table 2) _ Expansion, coefficient of____________ _ 11c Expansion joints ------------------31 
AGO 8488A 

Page 
28 75 
11,27 17 23 18 15 
37 46 11 63 49 46 18 34 74 68 35 
28 81 46 27 60 51 27 31,40 60 13 14 32 36 44 23 64 
80 69 72 55 79 
38 55 13 13 
6 13 12 43 
Pai'R.gn\ph 
Fasteners, mechanical --------------25 Fillers, metal ----------------------23b Fire prevention --------------------10 Flange joints ----------------------29c Flashing --------------------------33 
Flat seam roofing__________________ 34a Flux soldering --------------------26b 
Gable end flashing -----------------33h (3) Gages : 
Classification ------------------11b 
Recommended for duct con
struction (table 7) -----------
Table of sheet metal gages 
(table 1) ------------------Galvanized iron -------------------17 Gravel stops -----------------------33h (2) Guard, snow ----------------------41 Gutters ---------------------------35 
Hanging gutters -------------------35d Head, leaders ---------------------36d Hip and ridge flashing_____ _________ 33b Hood, range -----------------------48 
Iron, black ------------------------21 Iron, galvanized -------------------17 
Jack, smoke -----------------------43 Joints, expansion ------------------31 Joints, general ---------------------29 
Lap joints ------------------------29b Lead, general ---------------------16 Lead equivalent of concrete for shielding against X-rays (table 8) _ Lead sheets, thickness of (table 5) __ _ 
Leader heads ----------------------36d Leaders ---------------------------36 Leaf screens ----------------------35g
Linings, built-in gutters_____________ 35e Linings, radiator recess ------------40 Linings shower --------------------47 
Machinery, shop -------------------7b Maintenance, mastic and calking_____ 23d Maintenance, roofs and flashing_____ 45 Mastic and calking compounds_______ 23 Miscellaneous materials -----------22 Monel, general --------------------14 
N a ils -----------------------------25a 

Page 
29 28 11 36 46 62 32 
59 
12 
80 
12 20 58 73 67 
68 71 48 81 
26 20 
74 43 35 
35 19 
83 20 71 69 69 68 73 81 
7 98 75 28 27 17 
29 
93 


Paragraph 
Outlet, gutter  35[  
Pan, shower  ---------------------- 47  
Pan, splash  ---------------------- 37  

Parapet flashing -------------------33h ( 5) Patterns --------------------------9b Personn~ -------------------------6 
Plastics ---------------------------22b Practices : Shop 9 Trade 5 Precautions, shop ------------------10 Purpose --------------------------1 
Radiation shielding ----------------49 Radiator recess lining --------------40 Range hoods ----------------------48 References ------------------------App. I Reglets ---------------------------33h ( 8) Ridge flashing ---------------------33b 
Rivets and riveting_________________ 25c 
Roof drains -----------------------38 Roof projections, flashing___________ 33g Roofing, general -------------------34 Roofing seams ---------------------30a 
Saddles, chimney flashing___________ 33[ 
Safety ----------------------------3 Scope -----------------------------2 Screw fasteners -------------------25b Scuppers --------------------------38 Scuttles --------------------------39 Seams, general --------------------30 
Selection of materiaL______________ App. II Shielding, X-ray -------------------49 Shoes, leaders ---------------------36[ 
Page 
69 
81 72 60 10 
5 27 
10 5 
11 
3 
83 73 81 85 60 48 31 72 54 61 37 
51 3 3 
29 72 73 37 88 83 72 Shop layout -----------------------
Shower linings and pans____________ Sizing of gutters_____ ______________ Sizing of leaders___________________ 
Slip seams ------------------------
Slope of gutter_____________________ 
Smoke jacks ---------------------Snow guards ---------------------Soldering ------------------------Spandrel-beam flashing ------------Splash pans -----------------------
Standing seam roofing______________ Stiffeners, edge -------------------Stock -----------------------------
Stop, gravel ----------------------Stainless steel ---------------------
Tape, adhesive -------------------Terneplate (tin) -----------------Thickness of copper sheets (table 4) _ Thickness of lead sheets (table 5) --Thickness of sheet metal (gag·e) ____ Through-wall flashing -------------Tool s, hand -----------------------
Valley flashings ------------------Ventilators, roof -------------------
Wall flashings ---------------------Welding --------------------------Wood frame construction, flashings for --------------------Workability of metals______________ 
X-ray protection -------------------
Zinc, general 
Paragraph Page 
5 5 47 81 35a 67 36a 69 30a 37 35b 67 43 74 41 73 26 32 33d 49 37 32 34b 62 30b 38 8 7 33h (2) 59 20 23 
23a 28 
19 	22 14 20 
llb 12 33c 48 7a 6 
33e 51 42 74 
33a 46 28 34 
33h ( 6) 60 lld 12 
49 	83 
18 	20 
94 	AGO 8488A 
By Order of the Secretary of the Army : 
Official: 
J. C. LAMBERT, 
Major General, United States ATmy. 
The Adjutant General. 

Distribution: 
Active Army: 
USASA (3) 
ASA (I&L) 
CofEngrs (20) 
TSG (2) 
CSigO (2) 
DCSLOG (4) 
USCONARC (4) 
USAMC (4) 
OS Maj Comd (5) 
OS Base Comd (5) 
MDW (5) 

NG: None. 
USAR: None. 
For explanation of abbreviations used, see AR 320-50. 

EARLE G. WHEELER, 
General, United States A1·my, Chief of Staff. 
ZI Armies (5) 
Instl (10) 
USMA (2) 
USAES (100) 
Dep (10) 
Arsenals (10) 
Cen (10) 
Div Engr (5) 
Dist Engr (5) 
Engr Fld Maint Shops (2) 
AGO 8488A