ENGIN. LIB
TJ
DUPL
A 758,374 SSENDEN
164
P89
V.5
PIPING FOR POWER
AND
HEATING PLANTS
POWER PLANT
ENGINEERING
HANDBOOKS

C. H FESSENDEN
333 W. ENGINEERING BLDG.

ANN ARBOR,
MICHIGAN
POWER PLANT
ENGINEERING
HANDBOOKS
JAN - 1 1030
Piping for Power and
Heating Plants
TECHNICAL PUBLISHING CO.
Chicago, Ill.
Ine mering
Library
то
164
*
Copyright 1924. All rights reserved.
TECHNICAL PUBLISHING CO.
Chicago, Ill.
HONDA Uzban traghe

1
1
اتح
CONTENTS
Cut-
CHAPTER I. INSTALLATION OF PIPING SYSTEMS.
Taking Measurements for Pipe Lines.
ting, Threading and Making Up. Bending
Pipe. Methods of Supporting Piping. Colors
for Piping.
CHAPTER II. CONSTRUCTION OF PIPE JOINTS.
Screwed Joints Have Tapered Thread. Pur-
pose and Types of Pipe Nipples. Use of Pipe
Couplings. Use of Unions. Details of Flanged
Joints. Joints for Cast-Iron Pipe.
CHAPTER III. PIPE FITTINGS AND Bends.
Various Types of Screwed Fittings. Flange
Fittings Used With Large Pipe. Long Sweep
Fittings. Pipe Bends and Welded Nozzles.
CHAPTER IV. EXPANSION IN PIPING...
Coefficients of Expansion of Pipe Materials.
Methods of Taking Up Expansion. How Pipe
Bends Relieve Strains. Pipe Length Needed
for Bends. Cold Spring Relieves Strains on
Hot Pipe. Expansion Joints. Purposes and
Methods of Anchoring Pipe.
CHAPTER V. MATERIALS USED FOR PIPING..
Factors in Pipe Durability.
Wrought Iron
Piping. Cast Iron for Piping. Uses for Brass
Piping. Copper Piping. Types of Piping.
Lap-Welded Pipe. Butt-Welded Pipe. Drawn
Pipe. Riveted Piping.
CHAPTER VI. CORROSION OF PIPING AND ITS PRE-
VENTION
Deactivating Water. Protection for Inside of
Pipe. Coating Pipes to Prevent External Cor-
rosion.
CHAPTER VII. RADIATION LOSSES FROM PIPES....
Method of Calculating Radiation Loss. Ma-
terials for Covering Pipes. Insulation for Cold
Pipes.
сл
14
28
35
47
56
59
4
CHAPTER VIII. PIPE CAPACITIES AND FRICTION
LOSSES
Loss of Head in Pipes. Added Loss of Head
in Fittings and Valves. Flow of Steam in
Pipes. Wet and Superheated Steam. Effect
of Valves and Fittings.
CHAPTER IX. WATER PIPING SYSTEMS.
Suction Lines for Pumps. Suction Lift and
Head for Hot Water. Boiler Feed Lines.
Pump to Main. Feed and Service Piping.
Water Piping for Special Service. Cold Water
for General Service. Hot Water Supply Sys-
tem. Cold Drinking Water. Fire Service.
Hydrants and Hose Lines. Sprinkler Systems.
Pipe Sizes for Sprinkler System.
CHAPTER X. STEAM PIPING, MAINS AND HEADERS..
Arrangement of Steam Headers. Auxiliary
Steam Lines. Auxiliary Mains and Cross Con-
nections. Reduced Pressures. Draining Ap-
paratus. Separators to Remove Water. Holly
Gravity Return System. Draining Receivers.
Exhaust Steam Lines. Back-Pressure Valves.
CHAPTER XI. PIPING CONNECTIONS TO POWER
PLANT EQUIPMENT
Pipe Connections to Steam Pumps. Injector
Piping and Valve Arrangement. Feed-Water
Heater Piping. Boiler Feed Line Connections.
Feed Line Discharge. Water Column Connec-
tions. Blowoff Piping. Surface Blowoff.
Blowoff Tanks. Safety Valves. Steam for
Stoker Plungers. Soot Blowers. Pipe Con-
nections for Steam Engines. Steam Jackets
and Receivers. Turbine Piping.
Turbine Piping. Condenser
Piping. Condenser Systems. Jet Condensers.
Barometric-Condenser Connections. Surface-
Condenser Connections. Dry-Vacuum Piping.
CHAPTER XII. PIPING FOR EXHAUST STEAM HEAT-
ING SYSTEMS
Typical Exhaust Steam Heating Installation.
Size of Mains and Returns.
67
87
100
125
PI
CHAPTER I
INSTALLATION OF PIPING SYSTEMS
IPE lines should be kept as short as possible, the
number of joints reduced to a minimum, and in the
case of steam piping ample provision made for drainage
and expansion. Valves should be so arranged as to permit
cutting out of faulty sections without service interruption
and all covering employed should be applied in a neat and
durable manner and so as not to interfere with repairs.

W
(A)
(B)
FIG. 1. DIMENSIONS TO BE CONSIDERED WHEN TAKING
MEASUREMENTS FOR PIPE LINES
While roller-bearing saddles allow considerable freedom
of pipe movement, this type of support increases the
tendency of the pipe to vibrate. Many times, therefore, a
free-sliding support which allows the pipe to come and
go and at the same time places a damper on any tendency
to vibrate is preferable.
In taking measurements for pipe lines, it is customary
first to obtain the distance between the centers of the
fittings to be connected and then make the necessary
allowance for these fittings as at (A), Fig. 1, where X
represents the distance between the center of the elbow
and that of the tee, while Y is the actual required length.
For flanged fittings, make allowance as indicated in Table
6
I. For screw fittings, subtract from X twice the distance
from center to face; then add twice the distance pipe is
to enter fittings as indicated in Table II. Where specifica-
tions call for a simple U bend, the total length of stock
required may be determined by adding the sum of the
lengths of the two arms to the length of the curved portion
obtained by multiplying the radius of curvature by 3.14,
TABLE I. ALLOWANCE TO BE MADE IN PIPE LENGTHS FOR
FLANGED FITTINGS

Subtract for
1-1/4 1-1/2 | 2 2-1/2 3 3-1/2 4 4-1/2
10
5
6
7
8 9 10 12
Flanged
Std. 4
" Ex. Hy.
6
4-1/2 5 6
5-1/2 6 7
6
7
7 8
8
8
9 9
9 10 11 11 12 13 15
10
11 12 13 13 24 16
TABLE II.
LENGTH OF PIPE THREAD SCREWED INTO FIT-
TINGS TO PROVIDE A TIGHT JOINT

-A-

Pipe
Size
Dimension
A
Pipe
Size
Dimension
A
Inches
Inches
Inches
Inches
1/8
1/4
3-1/2
1-1/16
1/4
3/8
4
1-1/16
3/8
3/8
4-1/2
1-1/8
1/2
1/2
5
1-3/16
3/4
1/2
6
1-1/4
9/16
7
1-1/4
1-1/4
5/8
8
1-5/16
1-1/2
5/8
9
1-3/8
2-1
2
11/16
10
1-1/2
1/2
15/16
12
1-5/8
1
Dimensions given do not allow for variation in tapping or
threading.
CRANE CO.
all measurements being taken along the center line of the
pipe.
To estimate the length of an irregular curved line or
offset, make an exact scale drawing of the proposed work,
measuring along the center line by means of a tape line
7
or measuring wheel and multiply by the length of scale
employed.
When measuring offsets of 45 deg., as at "B" Fig. 1,
distance "Y" may be obtained by direct measurement along
the axis of try pieces t, t, or if this is inconvenient, by
multiplying "W," the exact distance between centers of the
two parallel pipe lines to be joined, by the secant of 45
deg., or 1.41 and subtracting from the result thus ob-
tained two times the distance between the center and the
inner end of the threaded portion of the fittings.
For 60, 30 and 22½-deg. fittings, multiply distance W
by 1.15, 2.00 and 2.61, respectively, to obtain X.
In the majority of cases and especially on small jobs it
is the duty of the man who is to install the new piping to
determine the quantity and sizes of piping and fittings
required. This may best be done by making a sketch
(preferably to some convenient scale) of the proposed lay-
out and from that determine the necessary number and
size of fittings and lengths of piping.
CUTTING, THREADING AND MAKING UP
Piping up to 2 in. in diameter may be cut by means
of a single wheel cutter, while larger sizes and that in
trenches or otherwise where impossible to give the cutter
arm a full turn, should be cut with a three-wheel cutter.
All sizes above 6 in. are usually cut with a hack saw or
cutting machine, the oxy-acetylene flame or the electric
arc.
In cutting and threading, care should be taken first
that there is no reduction of the internal diameter of the
pipe, and second that the thread is so cut as to give a
proper amount of make-up. Any burr made by the cutter.
on the inside of the pipe should be carefully removed and
the end of the pipe examined for cracks or splits started
in the cutting process. The length of the perfect thread
should correspond with that shown in Table III of pipe
rizes, but should not exceed such value in order to avoid
Lae joint leaking or the pipe entering the fitting too far
and throwing it out of alinement, or possibly in the case
of a coupling or tee causing interference between pipe ends.
In making up a pipe joint, it should be screwed
securely into place but not forced more than necessary in
8
TABLE III.
DIMENSIONS OF STANDARD WROUGHT PIPE
although, if absolutely necessary to use such a coupling,
flange form is to be preferred to a right-and-left coupling,
making up the final joint, a union, either of the screw or
likelihood of cracking them when steam is turned on. In
order to avoid producing a strain on the fittings and the

Diameter
Circumference
Length of Pipe
Per Sq. Ft. of
Length
of Pipe
Nominal Weight
Per Foot
Nominal
Internal
Inches
Approx- Nominal
Containing
Number
of
Length of
imats
External
Internal
External Internal Thickness External Internal
Surface
Surface
Опе
Cu. Ft.
Threads
Perfect
Plain Threaded
Ends
Per
Inghes
Inches
Inches
Inches
Inches
Peet
Feet
Feet
and
Coupled
Inch of
Screw
Screw
1/8
0.405
0.269
0.0€8
1.272
0.845
9.431
14.199
1/4
0.540
0.364
0.088
1.696
1.144
7.073
10.493
2533.770
1383.790 0.424
0.244
0.245
27
0.19
0.425
18
0.29
3/8
0.675
0.493
0.091
2.121
1.549
5.658
7.747
754.360 0.567
0.568
18
0.30
1/2
0.840
0.622
0.109
2.639
1.954
4.547
6.141
473.910
0.850
0.852
14
0.39
3/4
1.050
0.824
0.113
3.299
2.589
3.637
4.635
270.030
1.130
1.134
14
0.40
1.315
1.049
0.133
4.131
3.296
2.904
3.641
166.620 1.678
1.684
11-1/2
0.51
1-1/4
1.660
1.380
0.140
5.215
4.335
2.301
2.767
96.276 2.272
2.281
11-1/2
0.54
1-1/2
1.900
1.610
0.145
5.969
5.058
2.010
2.372
70.733 2,717
2.731
11-1/2
0.55
2
2.375
2.067
0.154
7.461
6.494
1.608
1.847
42.910 3.652
3.678
11-1/2
0.58
2-1/2
2.875
2.469
0.203
9.032
7.757
1.328
1.547
30.080 5.793
5.819
8
0.89
3
3.500
3.068
0.216
10.996
9.638
1.091
1.245
19.480
7.575
7.616
8
0.96
3-1/2
4.000
3.548
0.226
12.566
11.146
0.954
1.076
14.560 9.109
9.202
8
1.00
4.600
4.026
0.237
14.137
12.648
0.848
0.948
11.310 10.790
10.889
1.05
6.663
5.047
0.258
17.477
16.866
0.686
0.756
7.198 14.617
14.810
1.16
6.625
6.065
0.280
20.813 19.054 0.576
0.629
4/984 18.974
19.186
8
1.28
7.625
7.023
0.301
23.958
22,063
0.500
0.543
3.717 23.544
23.769
8
1.36
8
8.626
8.071
0.277
27.096
25.356
0.442
0.475
2.816 24.696 25.000
8
1.46
9
9.625
8.941
0.342
30.238 28.089 0.396
0.487
2.294 33.907 34.188
8
1.57
10
10.750
10.192
0.279
33.772
32.019
0.355
Q.374
11
11.750
11.000
0.375
36.914
34.558
0.325
0.347
12
12.750
12.090
0.330
40.055
37.982
0.299
0.316
13
14.000
13.250
0.376
43.982 41.626 0.272
0.288
14
16.000
14.250
0.375
47.124
44.768
0.254
0.268
0.903
16
16.000
15.250
0.376
50.625
47.909 .0.238
0.250
1.785 31.201 32.000
1.515 45.557 46.247
1.254 43.778 45.000
1.044 64.688
58.573
0.788 | 62.579
66.824
60.375
64.500
· CD CD CD CD ED M
8
1.68
1.77
1.87
2.00
8
2.10
2.20
9
care should be taken to have the fitting make up onto both
ends of the pipes so as to give a tight joint.
For steam-tight screw joints, many engineers use a
mixture of cylinder oil and graphite, although the follow-
ing mixture suitable for both steam and water pipes is
recommended: Ten pounds fine yellow ocher; 4 lb. ground
litharge; 4 lb. whiting and ½ lb. hemp cut up fine. Mix
thoroughly with linseed oil to about the consistency of
putty.

FIG. 2. METHOD OF BENDING SMALL PIPE
For ammonia pipe joints use a mixture of litharge and
glycerine. This filler sets so quickly, however, that only
enough for one joint should be mixed at a time, and when
the joint is once made it should not be disturbed as the
filler is useless if broken after having once set.
BENDING PIPE
Sizes of brass and copper pipes commonly employed.
and iron pipes 1 in. and less in diameter may be bent cold
in the following manner, care being taken when doing so
to have the seam on the inner curve: With a brace and
bit bore a hole about 1½ in. larger in diameter than the
pipe to be bent, in a solid well-supported soft pine timber.
Insert the pipe to the point at which the bend is desired
and make the bend by pulling slowly to one side, moving
the pipe in and out a little after each pull.
If any considerable bend is required, a form should be
made having the curvature to which it is desired to bend
10
the pipe, and while one end of it is held fast, the pipe
should be bent around this form. If the curvature is
sharp, fill the pipe with perfectly dry sand and heat it to
a red heat before bending, as in Fig. 2.
METHODS OF SUPPORTING PIPING
Frequency of pipe supports is determined more by
branch connection requirements and for the prevention of
vibration than by the weight of the piping itself. The
interval between hangers should, however, not exceed 12
ft., except for small pipe, which may be supported on 18-ft.
centers.

FIG. 3.
METHOD OF SUPPORTING RISER IN HEATING
SYSTEM
In vertical runs the risers are anchored only sufficiently
to prevent sidewise movement, the weight of the piping in
short lines being sustained by the connecting horizontal
runs or the branch connections as in Fig. 3. Long and
heavy vertical runs may be supported by means of a base
elbow, as at A, Fig. 4, resting upon a concrete pier and
steadied by guides at frequent intervals.
Medium size vertical runs may be supported as at B,
C and D, Fig. 4, the adjustable bracket support shown at
D being particularly well adapted where risers run parallel
to walls or columns.
Hangers suitable for both light and heavy piping are
shown at A to M, Fig. 5. These are generally attached
to overhead construction, clamps being employed for con-
necting to I beams, heavy eyebolts or lag screws for wooden
beams, or ceilings, while plates or bars are imbedded in
11
reinforced concrete, to which the hangers may be attached.
Where hollow tile construction exists the hanger may be
suspended as at K. Compensation for expansion and con-
traction and proper alinement of the pipe line is secured
by the use of swing joints, ball-and-socket joints and turn-
buckles. A more satisfactory provision for the movement
of pipe lines, however, consists of short lengths of piping



(A)
(8)
(C)
(0)
I


FIG. 4.
METHODS OF SUPPORTING MEDIUM-WEIGHT AND
HEAVY RISERS
or cast saddles capable of rolling on some form of center
pin, as may be seen by referring to E, I, L, S and T, Fig. 5.
Large and heavy piping, such as steam and exhaust
headers, air lines, water mains, etc., when not in trenches,
is generally carried on substantial wrought-iron or cast-
steel brackets securely bolted to side walls or columns, the
pipe resting in a cradle or a rolling saddle, adjustable in
both vertical and horizontal directions.
12
Floor stands, or pillars (N, O and P, Fig. 5), adjust-
able as to height, are generally provided with Y-shaped
brackets, although semi-circular brackets or cradles with
holding-down straps conforming to the curvature of the
pipe are preferable.
Pipe lines crossing alleys, streets, yards or courts where
the use of hangers or pillars is impracticable, require some.
exceptional form of suspension or bracing, as in Fig. 6.

(A)
(B)
(C)
(N)
από
10:
(F)
(J)

(GI

(K)
ан
(H)
(1)



(M)
(5)
131


(0) 1

(A)
(7)
(0)
FIG. 5. TYPES OF HANGERS, PILLARS AND BRACKETS
13
COLORS FOR PIPING
For the purpose of ready identification of piping sys-
tems, colors should be used on valves, flanges and fittings
only, with the piping proper painted to conform to the

(A)
W

(B)
W
FIG. 6. CABLE SUSPENSION AND BRACING FOR
LONG PIPE LINES
color scheme of the room.
mended are as follows:
Identification colors recom-
Steam division....
Water division..
Oil division..
Pneumatic division.
Gas division.
Fuel oil division.
a-High pressure-white.
b-Exhaust system-buff.
c-Fresh water, low pressure-
blue.
d-Fresh water, high pressure
boiler feed lines-blue and
white.
e-Salt water piping-green.
f-Delivery and discharge-
brass or bronze yellow.
g-All pipes-gray.
.h-City lighting service-alu-
minum.
•
i-Gas engine service-black,
red flanges.
j-All piping-black.
Refrigerating system....k-White and green stripes al-
ternately on flanges and
fittings, body of pipe being
black.
P
CHAPTER II
CONSTRUCTION OF PIPE JOINTS
IPE fitting is largely a matter of securing tight joints,
and great care and good judgment are required if
best results are to be had, particularly where high pres-
sures are used. In ordinary power plant piping, two types
of pipe joints are commonly employed; these are screwed

"
-0.028
M0.100"
Mus0.075"
4 THREADS-2THR. COMPLETE THREAD
INCOMPLETE FULL AT
ROOT
0.50"
-0.25
0.89"
FIG. 7. TAPERED THREAD FOR 212-IN. PIPE
and flanged joints. Where cast-iron pipes, such as water
mains, are used, the common joints are flanges cast on or
the bell and spigot type.
SCREWED JOINTS HAVE TAPERED THREAD
Screwed joints are the most common in small piping
and are frequently used in sizes as large as 8 and 10 in.,
although in the larger sizes screwed joints are difficult to
work with and many engineers recommend flanged joints
in all piping above 21½ in.
Pipe threads have two duties to perform, one to hold
the pipe ends together, the other to prevent leaks. The
standard machine thread would perform the first duty, but
in drawing the pipe ends together a slight opening is left
on one side of the thread through which steam can leak.
To overcome this difficulty the tapered thread was devised,
a section of which is shown in Fig. 7. With a tapered
thread on the fitting to match that on the pipe end, a tight
joint throughout the entire length of the thread is ensured
when the fitting is screwed up tight on the pipe end. In
Table III on pipe dimensions the length of perfect screw
15
is given, being represented by the space marked "complete
thread" in Fig. 7. The standard taper is 1 in 32 to the
axis of the tube.
PURPOSE AND TYPES OF PIPE NIPPLES
In pipe lines of considerable length, made up of screwed
joints, it is desirable to make some provision for opening
the line at one or more joints, otherwise the entire line
may have to be taken down to make some slight repair near
the beginning of the run.
Pipe nipples are short pieces of pipe threaded at both
ends, and are convenient in making up connections with

CLOSE
SHOULDERED
FIG. S.
R AND L
WITH HEX, CENTER
LOCKNUT
SEVERAL TYPES OF NIPPLES
screwed joints. They are made for all sizes of pipe and
any convenient length, and threaded right-handed, left-
handed or right-and-left handed, tapered or straight. The
right-handed nipple is used in cases where it is possible to
extend the pipe by turning a fitting and the right-and-left
where the fitting cannot be turned to extend the pipe.
To secure a tight joint against high pressure, the tapered
thread is almost a necessity and should be used wherever
possible; where a long thread is necessary, however, the
straight thread must be used.
Close nipples may be made by threading the end of
a pipe and cutting the threaded part off the desired length.
This gives a straight thread the entire length. The close-
shouldered nipple is threaded from both ends with a
tapered thread, the threads coming close together at the
center. Short and long nipples are alike, except for
length, the thread at each end being just the length to
enter the fittings. Nipples should be of extra heavy pipe,
as they are turned with a wrench and are easily distorted
in shape. Some stock nipples used for radiator connections
are made with a hexagonal nut at the center, have right
and left threads, and are turned with a thin wrench called
a spanner.
16
Locknut nipples or long screws are convenient in mak-
ing up final connections when a union is not at hand.
This consists of a short nipple with a tapered thread at
one end and a long thread at the other. A locknut made
by cutting off the end of a coupling and reaming it to give
a small recess for packing and a straight-thread coupling,
reamed in a similar manner, are screwed onto the long
thread of the nipple. With the pipe in place, the coupling
is screwed off the nipple onto the end of the pipe to half



OW
PLAIN
RIBBED "R, AND L
OFFSET


ミ
​1/1:
16

OFFSET REDUCING
MALE AND FEMALE
FIG. 9.
REDUCING
OFFSET REDUCING.
TYPES OF COUPLINGS IN COMMON USE
the length of the coupling, or until tight, and the locknut
is then screwed tight against the coupling with packing
made of lamp wick or hemp soaked in white lead in the
reamed space between coupling and locknut.
USE OF PIPE COUPLINGS
For connecting continuous length of pipe, the coupling
is used. This is really a sleeve with tapered thread inside.
Right-and-left couplings are sometimes used for final con-
nection when the pipes cannot be turned.
When connecting pipes of different sizes, the reducing
coupling is employed. This is a casting similar to the
coupling, except that one opening is reduced in size.
Offset or eccentric reducing couplings, with openings not
concentric, are employed where it is desired to keep one
side of the pipe run in a straight line as along a floor,
17
wall or ceiling. The offset male and female reducing
coupling is used to connect a fitting to a pipe of larger
size and is convenient in connecting up steam radiators.
The plain offset resembles a bent coupling and is used to
continue a run at an offset but parallel line.



HEXAGONAL
FACED OR FLUSH
ECCENTRIC
FIG. 10


SQUARE HEAD
COUNTERSUNK
FIG. 11


PLAIN
F16.12
RIBBED
FIG. 10. BUSHINGS OF STANDARD FORMS
FIG. 11.
CONVENIENT FORMS OF PLUGS
FIG. 12. CAPS OF FORMS COMMONLY USED
For connecting a pipe to an outlet of larger size, the
"bushing" is used similar to a coupling but threaded inside
and out with taper threads, usually right-hand. The faced
or flush bushing is threaded the entire length of its surface
and enters the fitting opening completely; another type
has an hexagonal portion for convenience in turning it
18
with a wrench. Bushings are also sometimes made eccen-
tric for convenience in connecting up piping.
Plugs are used to close tapped openings in fittings.
where pipe connections are not required. These are usually
made with a square head and right-hand tapered thread,
but the faced type is sometimes used to enter the fitting
flush to the opening and with a square depression in the
face by means of which it can be turned.

FIG. 13.
PART SECTIONAL VIEW OF STANDARD PIPE UNION
For dead-ending a pipe, a cap is used which is a hol-
low casting threaded inside. It may have a square pro-
jection, hexagonal or ribbed body or be entirely plain, but
is always threaded tapered, either right or left hand.
USE OF UNIONS
For making final connections the pipe union is the
most convenient fitting. It consists essentially of three
parts, two sleeves threaded to screw onto the ends of the
pipes to be joined, and a threaded ring to draw the sleeves
together and make a leak-proof joint. In the standard type
as recommended by the American Society of Mechanical
Engineers, a gasket is used to secure a good seating sur-
face, but in high pressure steam and water piping the
ground joint is preferable; the seat being made of non-
corrosive metal and with seating surfaces of the ball and
socket shape, absolute alinement of the pipes is not neces-
sary.
Unions are made up with any combination of threads
desired.
For the larger sizes of piping and higher pressures,
flanged joints are almost universally employed. The ad-
vantages are that the pipes do not have to be turned; any
individual length may be removed without disconnecting
the rest of the line, individual joints are more easily re-
19
paired, and a tighter connection can be made. Flanged
joints are, however, expensive and accurate alinement is
necessary, except where special provision is made.
DETAILS OF FLANGED JOINTS
Standard pipe flanges are cast rings which fit over
the ends of the pipe. When of the screwed type, the flange
is tapped and screwed on to the end of the pipe a sufficient
distance to secure proper strength.
TABLE IV. AMERICAN BRIGGS STANDARD FOR THICKNESS OF
SCREWED FLANGE

RING GAGE A
1
FLAT ON PLUG

Pipe Size
Adopted Thickness
of Ring Gage A
Pipe Size
Adopted Thickness
of Ring Gage A
1/8
1/4
3/8
3/4
4824
0.1801
0.200
5
0.937
6
0.958
0.240
7
1.000
0.320
8
1.063
0.339
9
1.130
1
0.400
10
1.210
1-1/4
0.420
12
1.360
1-1/2
0.420
14
1.562
2
0.436
15
1.687
2-1/2
0.682
16
1.812
3
0.766
18
3-1/2
2.000
0.821
20
2.125
4
0.844
22
2.250
4-1/2
0.875
24
2.375
In Table IV is noted the American Briggs standard
recommended by the American Society of Mechanical En-
gineers. In some cases a boss is cast on the flange, making
possible the use of a longer thread. One side of the flange
is faced to fit accurately the flange of the joining pipe.
Holes are drilled for bolts to hold the companion flanges
together, standard practice using four or multiples of
20
four bolt holes in the flanges. Some flanges have recesses
into which the heads of the bolts fit to prevent them from
turning. Another provision sometimes made is a calking
recess to be filled with lead as an extra precaution against.
leaks.
Flanges are sometimes shrunk, peened and riveted to
the pipe. The method employed is to turn the end of the
pipe smooth for the length of the flange, bore the hole in



SCREWED
고
​LA MOD
ዝጋ
CALKING

RECESSES FOR BOLT
HEROS
теб
CALKING
RECESS



PEENED ANDRIVETED
FIG. 14.
FLARED
WELDED RING
SECTIONS THROUGH FLANGE JOINTS
the flange slightly smaller than the outside diameter of
the pipe, heat the flange, insert the pipe and allow it to
cool. The inside end of the flange bore is chamfered, the
end of the pipe is peened out into this chamfer and rivets
are put through the pipe and flange, making the joint
doubly secure.
Flanges are sometimes held on the pipe by flaring the
end of the pipe after the ring has been slipped on. In this
case the ring fits loosely around the pipe, forming what is
called the Van Stone joint. The end of the pipe is flared
out and faced up true to give a surface against which the
next pipe end fits. The flanges in this case merely hold
the ends of the pipe together. As the pipe end is flared
21
it becomes thin and the flange is sloped slightly to give
even contact or the pipe is upset before being flared in
order to prevent the thinning out.
With modern methods of manufacture, the Van Stone
joint is made with additional metal at the turn and the
water pocket right at the joint has been eliminated. This
type of joint greatly facilitates erection because the flanges
can be easily turned to match bolt holes. It is a first-class



о
PLAIN
FINISHED RING
CORRUGATED
GROUND


÷ +
TONGUE AND GROOVED
MALE AND FEMALE
FIG. 15. TYPES OF FLANGE FACES
commercial joint which is dependable, and suitable for
high pressures. Pipe manufacturers have recently de-
veloped a method for Van Stoning genuine wrought iron
pipe.
A modified form of the flared joint is the welded ring
type in which a ring is welded to the end of the pipe. The
loose flange fits a 45-deg. seat on the back of the ring and
with its companion holds the pipe ends together. This
type of joint allows the pipe to be turned and is particu-
larly convenient in connecting up bent pipes.
Various forms of flange faces are used, the most com-
mon being the plain face which has the entire side of the
22
flange smoothed free of irregularities. Another common
form of flange is faced around the opening a short distance,
but the rest of the surface is turned down, giving a recess
between the outer edges of the flanges when the joint is
made up. A modification of this is a flange with a cor-
rugated face, as illustrated herewith, the ground face con-
sisting of several concentric rings of metal projecting
from the body of the flange.
Tongue and groove, and the male and female types of
flanges are extensively used for high-pressure piping as



O
FULL FACE
RING INSIDE
BOLT CIRCLE
A

B

C
FIG. 16. GASKETS FOR FLANGE JOINTS. A, FORMS OF
FIBROUS GASKETS; B, SIMPLE COPPER RUBBER FILLED; C,
FRENCH TYPE VICTOR; D, ALL COPPER CORRUGATED
these forms prevent the blowing out of gaskets. Ground
joints are no different from those described above except
that greater care is taken to give an exact fit between flange
faces, the surfaces being accurately ground to fit so as to
need no gaskets.
The ball-shaped flange with inserted noncorrosive rings
is coming more into use; no gasket is necessary and the
ball joint allows a reasonable misalinement of the pipe;
it is similar to many screwed unions.
Flange faces that are not ground are fitted together
with gaskets made of material suitable to the pressure,
temperature and fluid handled. Soft gaskets are made of
23
fibrous and composition materials and can be purchased
already cut for common pipe work, but are often cut from
sheet packing carried in stock, except when doing a big
piping job. It is common with plain-faced flanges to cut
the gasket full size of the flange with holes for the bolts.
as well as for the pipe openings. This is not necessary,
however, as the gasket may be cut with a smaller diameter,
allowing it to be inserted within the bolt circle, which
form is also easier to install.
Gaskets must have sufficient strength to withstand the
pressure under which they work, and this limits the use

7"″EX. HY PIPE
16-3°
BOLTS
FIG. 17.
SECTION THROUGH EDWARD WELDED JOINT
of soft gaskets to moderate and low pressures, although
soft gaskets reinforced with wire cloth may be used where
pressures are comparatively high. Where the face of
the flange is of the tongue and grooved type soft gaskets
may be used to advantage on high pressures, as they cannot.
be blown out of the joint. Several forms of copper gaskets
filled with asbestos or other fibrous material to give them
the elasticity necessary for filling up the small irregu-
larities of the flange face are on the market and give good
satisfaction in all kinds of high pressure piping. All
copper corrugated gaskets, also those having corrugations
filled with asbestos, are patented articles, and procurable i
standard sizes on the market. Even a plain soft copper
wire in the shape of a ring also makes a serviceable metallic
24
gasket. One of the principal advantages of metallic
gaskets is the fact that they can be used over and over
again.
Recently solid aluminum gaskets have come into quite.
extensive use and for extreme high pressures and tem-
peratures around 700 deg. F., they are reported to be well
suited.
In some cases no flanges are used, the ends of the
pipe being welded solidly together; this makes a solid.

45
45'
-30°
PIPE
FITTING
-30-0
45"
<PIPE FLANGE
FIG. 18. SARGOL JOINT PRESENTS SMOOTH INSIDE SURFACE
pipe line, and for permanency is unexcelled. The Edward
welded joint, Fig. 17, is applicable to joints between fit-
tings or between pipe and fittings, or a flange union. In
this joint the companion flanges, or a flange of a fitting,
must be especially prepared, as shown in Fig. 17. Com-
panion flanges fit loosely on the pipe, and as shown, the
end of the pipe is flared and rolled back, the outer edge
being suitably machined for welding and the face machined
true.
The welding takes place in the small "V" shaped
opening between the two ends of the pipe. The general
dimensions and the bolting of the flanges for this joint
are a great deal heavier than called for by the accepted
standards for extra heavy fittings.
25
Increasing steam pressures up to 600 to 1200 lb. and
correspondingly high temperatures have brought about.
the development of the Sargol welded joint. This joint
is made as shown in Fig. 18. The pipe end is upset sim-
ilar to the Van Stone joint, but is specially machined for
welding while the fittings have a special face as shown.
No gaskets are used, the weld being used to seal the joint
while all of the stress is taken by the bolts and not on
the weld. In putting up this joint, temporary bolts are.
used while the welding is being done which bolts are
replaced when the weld is completed.
Using the ordinary cold rolled steel, the strength of
which decreases rapidly with increase of temperature.

FIG. 19.
SAME DIAMETER AS
ROOT OF THREAD
SPECIAL STUD BOLT USED ON HIGH-PRESSURE
STEAM LINES
above 500 deg., it is practically impossible to get in enough.
bolts to give the required factor of safety. This has led
to the use of special alloy steels, usually a chrome-nickel
alloy, having a higher tensile strength and less affected
by temperature. Some of this material has a tensile
strength of well above 100,000 lb. per sq. in. with an
elastic limit of over 75,000 lb. per sq. in. All bolting
should be done with double-ended studs instead of bolts
on account of the crystallizing effect of the upsetting
process on the bolt head. On account of the pipe stresses,
which cannot be calculated, the bolt stress calculated at
the root of the thread, and figured at the outside diameter
of the gasket or welded joint should not exceed 5000 to
6000 lb. per sq. in.
Due to the fact that in the ordinary stud the tendency
is for all the elongation to take place at the root of the
threads not engaged in the nut, where the diameter is the
26
smallest, a special stud used to distribute this elongation
over a greater length has advantages. A sketch of this
stud is shown in Fig. 19.
JOINTS FOR CAST-IRON PIPE
While the small sizes of cast-iron pipe are put to-
gether with screwed joints, the sizes ordinarily used for
conveying water have flanged joints with the flanges cast


:85"
40°
UNIVERSAL
BELL AND SPIGOT


FLEXIBLE JOINTS
FIG. 20.
CAST-IRON PIPE JOINTS
on the end of the pipe, the type illustrated as Universal
in Fig. 20 being most commonly used. The flanges are
turned to a finish and the bolt holes drilled at the factory
or shop before delivery to the job.
Flanged piping requires very careful alinement and
for underground lines such careful work is next to im-
possible, so the bell and spigot joint is most commonly
used for this work. All cast-iron bell and spigot-type joints.
are of the same form and shape in regard to the bell and
bead of the spigot, regardless of size; that is, the lead
27
space and oakum space are the same, whether the pipe is
4 in. or 30 in. in diameter. The sketch shows these
dimensions.
When putting in the oakum, drive it hard and even
with a yarning tool up to the joint of the taper in the bell,
keeping the pipe centered so as to obtain an even lead
space all around. After the oakum is driven the pouring
band is put on and holes stopped up with mud. The lead
is heated until it will char a pine stick, then poured. The
lead is then driven up, the procedure being first to drive
up and cut off the pouring gate, then with a small tool,
beginning at the bottom, drive the lead hard, finishing
with a tool that just fills the lead space.
For pipe lines in uneven ground and at the bottom
of streams, a flexible joint is necessary. Two types of
flexible joints for cast-iron pipe are illustrated in Fig. 20;
these give the proper flexibility, yet when properly made
up will hold against common pressures.
CHAPTER III
PIPE FITTINGS AND BENDS
EVICES for putting lengths of pipe together are
generally called pipe fittings. These may be either
screwed or flanged, depending upon the size of pipe and
pressure maintained in it. Among the screwed fittings we
have ells, tees, y's, crosses and special fittings.
The



90°
45°
FIG 21
RIGHT AND LEFT



REDUCING
SIDE OUTLET
FIG. 22
STREET




STRAIGHT
REDUCING OUTLET
REDUCING
FIG.23
FIG. 21.
FIG. 22.
BULL HEAD
STANDARD FORMS OF ELBOWS
SPECIAL FORMS OF ELBOWS
FIG. 23. FORMS OF TEES
term "ells" is the tradesman's contraction of the word
elbows, which are fittings used to change the direction of
pipe run, the standard ells having openings at 90 and 45
deg. from the straight run. These are threaded right-
handed, or may be secured right-and-left, the latter being
used where fittings cannot be turned on the end of the
29
pipe. The openings for connecting onto the pipe are rein-
forced over the threads to insure proper strength. When a
right-and-left ell is used, it is common to designate the
left-hand-thread end in some way, such as having this
opening ribbed.
Reducing ells are modified forms of the straight ell, in
which one of the outlets is smaller than the other. These
are always threaded right-handed, unless made to special
order. The side outlet or 3-way ell is seldom used, except
for connecting drips, owing to the difficulty in allowing
for contraction and expansion, due to heat.
Street elbows derive their name from their most com-
mon use in connecting a service pipe of a water or gas
system. They take the places of an ell and a close nipple,
being threaded with male and female threads. This fitting
is convenient in places where a right angle turn must be
made in close quarters and is sometimes used by steam-
fitters in connecting water columns from the upper side
of the boiler drum beneath the brick work where space is
limited.
Tees, as the name implies, are fittings having three
connecting outlets which take the form of the letter T.
These are used to take branches from the main pipe at an
angle of 90 deg. without changing the direction of the
main run. Any number of branches may be taken from
the main line by inserting tees in the line. Standard
tees are always made with right-handed threads, but may
be secured with left-hand threads by special order. Tees
may be secured with any standard size of opening for any
of the outlets. In ordering it is necessary to designate
the size of the run, then the size of the branch, as 1 by 1
in. or straight 1 in. if the run openings are of the same
size. If not it is necessary to name the large run first,
then the small run, then the branch, as 112 by 14 by 1
in. When the branch is smaller than the main pipe the
fitting is called a tee with a reducing outlet. The term
reducing tee applies to fittings where the run is reduced
in size, as in the above case. "Bullhead" tees have the
run smaller than the branch, and are used when the pipe
branches both ways.
Y branches are in reality angle tees, that is, tees with
a 45-deg. angle branch from the run of pipe. These are
30
made in straight sizes; that is, with the openings all the
same size as standard stock, but may be secured in reducing
sizes by special order. Y branches are designated as are
tees, as explained above.
Crosses are used where two branches opposite each other
are taken from the main run and at 90 deg. from it.


CROSS
F16.24



DIVISION TEE
O.S. FITTING
DISTRIBUTING FITTING



SUCTION TEE
OPENING LOOKING
TO THE RIGHT
OPENING LOOKING
TO THE LEFT
SIDE OUTLET
TEES
FIG. 25
FIG. 24.
THE Y AND CROSS
FIG. 25. SEVERAL FORMS OF SPECIAL FITTINGS
There is an objection to the use of crosses due to the inter-
ference of flow to the branches.
A special fitting known as a division tee is used to
deflect the flow of the fluid to the branch, by this means
delivering more to the branch than the main run. This
is done by providing a partition part way across the run
of the tee. A modification of the division tee is the O. S.
fitting, which has a curved partition, causing the branch
to be favored. A similar fitting, but with a shorter par-
31
tition, is the distributing fitting, which has a large body
at the branch and a short deflector on the run.
What is known as a suction tee has a conical nozzle,
similar to an injector, pointing in the direction of the
flow, which induces a flow from the branch pipe. The
suction tee can be used to advantage in making up all
connections on heating jobs. Where condensation returns
to the boiler, they are recommended for connection where
two returns come together; also where the pipes are in
different sections, one section may be used to make the
other circulate. They are also used where two or more
connections are made to the same steam trap, as they will
cause all the condensation to flow freely into the trap and
avoid the trouble of one backing up on another. In this
way, it is stated, one steam trap can be used to answer
for several different connections, avoiding the necessity
of putting steam traps on each return if all are from the
same boiler.
The side outlet tee is a fitting with connections for
straight run and two branches at right angles to each other.
These may be secured with any size of opening for stand-
ard pipe. When ordering side outlet tees with reduced.
openings care must be taken to designate the openings
properly, and it is advisable to draw a sketch to accom-
pany the order. It is customary to name the large run
first, then the small run, next the large branch, then
the small branch, stating whether right or left of the
branch looking in the direction of run, as 2 by 1½ by 1
by 1 in., side outlet looking to right or to left, as illus-
trated.
FLANGE FITTINGS USED WITH LARGE PIPE
Whenever the piping is large, or the pressure within.
it is high, it is advisable to use fittings with flanged out-
lets. Standard flanged fittings are made in all the shapes
mentioned above, the flange being cast direct to the body
of the fitting. Fittings are made of cast iron, semi-steel
or cast steel to suit the pressure carried in the pipes.
recent practice it is common to have the fitting welded
directly to the pipe, the two being held together by bolts
through flanges, while the edges of the contact faces are
welded by means of the acetylene process. For this pur-
In
32
pose wrought iron or steel piping is used, while the flanges
fit loosely over the ends, which is an advantage in making
up the pipe system. Flanges for pipe-fitting are similar
in all respects to those used in straight pipings which were
described previously. In Table V are the standard dimen-
sions as adopted by the manufacturers of America, and
the American Society of Mechanical Engineers for both
low and high-pressure fittings.
LONG SWEEP FITTINGS
With the standard fittings the radius of curvature is
small, resulting in a quick turn of the fluid and consid-
TABLE V.
DIMENSIONS OF STANDARD FLANGE PIPE FITTINGS
(All dimensions are in inches and refer to
letters in Fig. 26.)

Size 1
1}} 1}
2 2 3 34
41 5
7
8
9 10 12 14 16 16
18- 20
AA 7
78
9
.O
10 11 12 13
14
A
3 32 4 4
صرية
5
54 6 }
7
7}
15 16 17
8
18 20
22
81
9
10
11
12 14
24 28 29 30
15
33 36
14}
B
55
516617
7 8 9
9)
C
11 2 2 2 3
221
3
314 4
D 7} 8 9 10 12 13 14 15 15
10 11 12 14
4) 5 5 51
17 18 201 22
15 16
16 18
19 21 22 24 26) 29
E 5261 7
00
F
A
113 2
223 3 3 3
91 1011112 12}| 13}| 14; | 16|| 17}
31 31
4;
43
6 6
24 25 30
19}|| 20{| 241
5 5
71
7}
8
8
81 91
33
34 36
39
43
27
28 30
32 35
'8. 6 61
7
00
8
C
5 6 7
71
8
9
10 11 11
12
14
18 17 18 19 20
H
A
4} 5 6 7
7 8 9
9 | 10
11
12 13 15
16
19
21 22 23 25
271
I
}
1
16
1½ | 11 | 11
1 1
18
1
11 IH
K
to to to it to a
}
?
13
}
3
11 1 11
L
3
31314151
6
7 7 7
91
10 112 131 141 17
183
20
211 | 221
25
ΣΖ
M
4
حكم
4
4
4
8
8
8
8
8
12
12 12 12
1-6
16 16 20
N to th
}
?
3
ដី
3
1 18
11
11
Size 22 24 | 26 | 28 | 30 | 32 | 34 | 36
38
40
42
44
46 48
50 52
54
56 58
60 62
AA 40 44 46 48 50 52 54 56
58
60
62
64 66 68 70 74 78
82 84 88 90
A 20 22 23 | 24 | 25 | 26 | 27 | 28
29
30
31
32
33 34 35 37
39
41 42 44 45
B
|31|| 34 |36|| 39 |41|| 44 46) 40|| 511 54 564
59 611 64 66 69 714 74 76j 79 81
OA
10 11 13 14 15 | 16 | 17 | 18 19
20 21 22 23 24 25 26 27 28 29 30 31
D
4649 53 56 59
F
37140) 44 46 49
F
89 99}| 10.
Ꮐ
222426 28 30 32 | 34 | 36 38 40 42 45 16 48
60
52
FI
I
K*
291 32 341 361 387 411 432 46 | 484|501 | 53
1H1 2 2 2 2 2 21 21 25 21
1111111111111
121
L
271 291311 34 36 38 40 421 45) | 471 491
N 17 17 11 12 12 13 13 13 18
M 20 20 24 28 28 28 32 32 32 3636
18 | 18
1
53 55 571 59 012 64
212 27
2H 21 21 21
1814 2 221
512 531 56 581 604 631
|
| ||
40 40 44
44 44 44
11 11 11 11 13
|
3
54 56 58 60 62
661 681 71 73 761
3 31 31 31
222 2 2 24
65 67) 69171}
48 48 52 62
11 11 11 11
*Minimum.
L-Bolt circlo.
M-Number of bolts.
N-Size of bolts.
33
erable resistance to the flow. To overcome this loss, long
sweep fittings have been designed, which have a radius of
curvature two times the ordinary fittings. The common
fittings made up with a long sweep are ells, double branch
ells, tees with straight backs and crosses. The illustration
shows the shape of these fittings.



H
L.
B
FIG. 26.
A
A
·A·



A
A
A
A


G-
E
STANDARD FLANGE FITTINGS
A




LONG SHEER
EL BOW
DULELE BRANCH
ELBOV
TEE
TEE WITH
STRAIGHT BACK
CROSS
FIG. 27.
LONG SWEEP FITTINGS
34
PIPE BENDS AND WELDED NOZZLES
Where high velocity of flow is maintained and extreme
economy in transmission is desirable, it is customary to
employ pipe bends in preference to the standard fittings.
These are usually made of lap-welded steel pipe with
flanged joints. They are made in special shapes to form
offsets or cross-overs, or to care for expansion. As a rule

QUARTER
BEND
SINGLE OFFSET
QUARTER BENDE
U BEND
OFFSET 45 BEND
CROSS OVER
DOUBLE OFFSET
U BEND
EXPANSION U BEVD
SINGLE OFFSET
U BEND
FIG. 28. STANDARD PIPE BENDS CARRIED IN STOCK
pipe bends are made especially for the job at hand, but
some shapes are carried in stock.
Where the pipe bends of large pipe are required, it is
better to have the bending done at the shop in order to
insure proper workmanship, but in small pipe work the
bending may be done at the plant.
Due to the liability of imperfections in cast manifolds,
the metal now commonly used for this purpose is wrought
steel to which the nozzles are welded by the acetylene
process, which insures homogeneous metal in the manifold
and absence of leaks.
For lower pressures, cast manifolds and distributing
headers are used, these being made of cast-iron, semi-steel
or cast steel with flanged joints.
CHAPTER IV
EXPANSION IN PIPING
ITH rise in temperature all metals expand in all
W directions, but the expansion in diameter of pipes
is so small as to be of no consequence. The lengthwise.
expansion, however, must be taken care of in order to
avoid excessive stress in the metal and straining at the
joints.
The amount of expansion is proportional to the rise
in temperature, to the length of the pipe, and to the co-
efficient of expansion, which varies with the temperature
and is also different for each metal.
In using a value for the coefficient it should, therefore,
be taken at about the average temperature at which the
pipe will be used. Cast iron and brass piping are used
TABLE VI.
Bronze
COEFFICIENTS OF EXPANSION IN INCHES PER
INCH OF LENGTH AT COMMON TEMPERATURES
Brass
Cast Brass.
0.0000111 Wrought Iron....0.0000075
.0.0000105 Steel
..0.0000100
Cast Iron.
•
..0.0000072
..0.0000062
..0.0000095
Copper
mostly for feed water or exhaust. The coefficient would,
therefore, be taken at around 200 deg., while for wrought
iron and steel piping, largely used for steam, the coefficient
should be chosen for an average of 350 deg. The coeffi-
cients for practical use in power plants have been so
chosen, and the values are as given in Table VI.
Since the length of the pipe run is usually measured
in feet, it is convenient to express the formula for ex-
pansion in terms of the length of the pipe, in feet, and
the rule is the total expansion, in inches, will be twelve
times the coefficient of expansion from Table VI times
the length, in feet, times the temperature rise, or as a
formula, E12 C L (T₂-T,). For ordinary condi-
tions, T₁, the initial temperature, may be taken as 60 deg.,
and the value of T₂ for saturated steam will be that
shown in the steam tables, corresponding to the pressure
carried. For superheated steam the degrees of superheat
2
36
FIG. 29.
GAGE LB.
STEAM PRES
6000899
VOG AW
DO O GOG
Jur NNN
90
M
TEMP RANGE DEG. FAHR.
LENGTH OF PIPE RUN
4
3
2
EXPANSION PER 100FT. INCHES
10
LENGTH OF PIPE BEND-FEET
30
20
40
50
DIAGRAM FOR EXPANSION OF PIPE AND LENGTH OF EXPANSION BENDS NEEDED
2014
क्षि
42
must be added to the temperature of saturated steam in
order to get the value for T₂.
This expression for expansion has been reduced for
quick use to the form of a diagram, the left half of Fig.
فا
12
18
ju ju
RADIUS FOR EXPANSION BENDS

☺ ☺
37
29, the axis on the left-hand side showing the temperature
rise, with a secondary scale which corresponds to the rise
for a given boiler pressure and saturated steam above an
initial temperature of 60 deg. The method of using this
diagram is indicated by the dotted line. For a boiler
pressure of 150 lb., start from the left-hand axis and fol-
low horizontally to the diagonal for the pipe material to
be used, in this case steel, then follow vertically to the

B
A
FIG. 30.
SINGLE AND RETURN SWING OFFSETS
diagonal corresponding to the length of the pipe run, in
this case 150 ft., and then to the right to the middle axis,
where the total expansion in inches will be read, in this
case amounting to about 3.63 in.
METHODS OF TAKING UP EXPANSION
Three methods are in use for taking care of expansion.
-the swing joint, the pipe bend and the expansion joint.
Each has its uses, but the swing joint is probably the least
useful of the three. In any case, the swing joint, which
is only applicable to screwed joints, should be used only
for pipe 6 in. in diameter or smaller, and where the ex-
pansion is limited in amount, generally for low-pressure
work. It is accomplished by an offset in the pipe, which
may be a single offset as indicated at A, Fig. 30, if such
is permissible in the pipe run, or if the pipe must be
continued in the same line as the original run, a return
offset must be made, which would be as shown at B. The
intent is, that the expansion shall be taken up by the
movement between fittings and pipe ends at the joints.
For most cases, pipe bends offer a satisfactory and eco-
nomical method for taking up expansion, but the difficulty
is to provide room for them, since in order to avoid strain
on the fittings and excessive stress in the bends, a con-
38
siderable length of pipe must be used, especially in large
sizes. The bends have the advantage over the offset method
of saving in the number of joints required, saving in the
length of pipe and decrease in the cost of erection.
How PIPE BENDS RELIEVE STRAINS
Expansion is taken care of entirely by the spring in the
pipe, and it makes no difference whether a straight length
of pipe be employed, if this is possible, as in the case of
turning a 90-deg. corner, or whether the required length
of pipe to take up the spring is fashioned into a bend of
one of the forms shown. In any case, the bend to take up

O

FIG. 31. SPECIAL FORMS OF EXPANSION BENDS:
CIRCLE, TWIST, LOOP
the expansion should be made from a single length of
pipe, if possible. This is limited in the case of curved
bends by the radius to which the bend may be made. This
should, wherever possible, be six diameters of the pipe,
which limits the use of the U bend in a single length to
12-in. pipe or under, since the pipe ordinarily comes in
lengths of not over 20 ft. In the case of the double bend
or the loop, it will limit the single length construction
to 6-in. pipe or smaller, and if such a form of bend is re-
quired in larger pipe, it must be made up of two or more
lengths with a joint at the middle of the bend. For
constructional reasons, there should be a straight end be-
yond the curve in any form of bend, of a length 1 to 2
times the diameter of the pipe, the larger figure being
used for large pipe; and for joining bends to the pipe line
or for making joints in bends, extra heavy flanges should
be used with Van Stone joints, or with the flanges welded
to the pipe.
39
Care must be exercised in the selection of pipe for
bends. Crane Co.'s recommendations are shown in the
accompanying table:
THICKNESS OF PIPE FOR VARIOUS BENDS
Radius
UP TO 125 LB. WORKING PRESSURE
Pipe Size
Pipe
4 to 5 diameters.. 7 in. and smaller.....Extra strong.
S in. and larger......½ in. thick.
Over 5 diameters.. 7 in. and smaller.....Full weight.
S in.
10 in.
12 in.
..28.55 lb. per ft.
.40.48 lb. per ft.
49.56 lb. per ft.
16
in. thick.
in. thick.
in. thick.
14 in. to 16 in., incl... .
18 in. to 22 in., incl....3
24 in. to 30 in., incl... .
16
125 LB. TO 250 LB. WORKING PRESSURE
4 to 5 and 6 diams. 7 in. and smaller.... Extra strong.
8 in. and larger..
Over 6 diameters.. 7 in. and smaller..
8.in.
10 in.
12 in.
1/2 in. thick.
.Full weight.
.28.55 lb. per ft.
..40.48 lb. per ft.
.49.56 lb. per ft.
14 in. to 16 in., incl... .3% in. thick.
18 in. to 22 in., incl.. 7 in. thick.
• •
16
24 in. to 30 in., incl....½ in. thick.
125 LB. TO 350 LB. WORKING PRESSURE
4 diams, and over.. 7 in. and smaller.....Extra strong.
8 in. and larger......½ in. thick.
There is always tendency to spring the ends of the
pipe run horizontally if a bend is laid horizontal, or ver-
tically if the bend is installed vertical. The horizontal
spring may be inconvenient if the ends of the pipe run
are rigidly held, while the lifting due to the action of a
vertical bend has but little inconvenience, but the vertical
bend forms a pocket, which will prevent the passage of
condensation and must be carefully drained.
40
As already stated, the expansion which can be taken
up by a bend depends on the length of pipe in the bend
and not on the shape. An extended discussion of this
was given by Taggart in the Transactions of the American
Society of Civil Engineers for December, 1910, and curves
worked out for the permissible strain in the pipe con-
sidered as a beam, with an outside fiber stress of 12,000
lb. to the square inch, which gives a factor of safety of 5.
The length necessary in the expansion bend will depend
not only on the expansion in the straight run, but also

ANCHOR
20
30-0
5"
SADOLE
-60"R
ANCH
-6-0
FIG. 32. ANCHORING AND ALLOWANCE FOR BRANCH
EXPANSION
on cross expansion of branches which may tend to deflect
the main run. It is, therefore, desirable, in the installation
of piping, to anchor the main run close to the point where
a branch is taken off, and provide for taking up the ex-
pansion of the branch away from the main run of pipe.
If an expansion bend is installed in the middle of a run
of pipe, the center of the bend should be anchored and
the bend take up the expansion both ways from the middle.
It is usually better, however, to install the expansion bend
at the end of the run of pipe or close to an anchor and let
all expansion be taken in one direction. In making up
the bend, care should be taken that the seam is on the side
of the bend, so that it is subjected neither to compression
nor tension when making the bend.
41
PIPE LENGTH NEEDED FOR BENDS
Along the line of Taggert's discussion, Raynes gives as
a formula for the length of pipe to take up the expansion
of a given run, the following, 1=KvdXLX t; where
I is the length in feet, of pipe to take up expansion; d is
the external diameter of the pipe, in inches; L is the length
of the expanding run, in feet; t is the temperature rise;
K is a constant whose value for wrought iron and steel
is 0.043; for cast iron, 0.057.
Taggart's values, where the arrangement is such that
cross expansion may be neglected, have been embodied in
the curves of the right-hand side of Fig. 29 to permit of
direct reading of the length required in the pipe bend.
To show the use of these curves, for a main run of 150
ft. of 6 in. pipe to carry steam at 150 lb. pressure, we
have, as shown on the left-hand side of Fig. 29, to care
for an expansion of 3.63 in. We wish to install a circle
bend to take care of this expansion, and from the middle.
axis of Fig. 29, follow to the right to the curve for 6-in.
pipe, and vertically down to the horizontal axis it shows.
that a length of approximately 35 ft. must be provided in
the bend. This is greater than the single length of pipe,
so that two sections must be used with a joint at the
center. It would be better to use two full lengths or 40
ft. in the bend.
The minimum radius of 5 times the diameter of the
pipe would be 30 in., which would give a semi-circle having
a circumference of about 8 ft. We must, therefore, use
a radius larger than this in order to include 40 ft. in the
circle bend. If we use a 60-in. radius, the length of the
semi-circle will be 15 ft. 9 in. To this there must be
added in. for the straight end next to the center joint,
which will, of course, give an elliptical bend instead of
circular. This will be a length of 16 ft. 4 in., which, taken
from the 20 ft. of a full pipe length, would give 3 ft.
8 in. as the horizontal leg to connect to the main run.
This will give a convenient form for erection and will,
therefore, be satisfactory. The loop is shown in Fig. 32.
On the right-hand side of Fig. 29 the cross curves show
the minimum radius for bends for the different size pipes,
indicated on the axis to the right, and the length of each
42
straight end to be allowed beyond the bent portion indi-
cated on the short axis to the left. For instance, for the
6-in. pipe where the straight end curve crosses the 6-in.
curve, follow to the left and we find about 7 in. as the
straight end required. Where the minimum radius curve
crosses the 6-in. curve, follow to the right and we find
about 30 in. as the minimum radius for the bend.
One difficulty in the use of bends in large pipe—that
is, the great length required to take up expansion of a run
of considerable length-may be overcome by using a multi-
ple branch bend between two headers. The area of the
several pipes in the bend should equal or exceed the area
of the main line, but the expansion taken care of by the
bend may be the same as if there were a single pipe of
smaller diameter. For instance, a 12-in. pipe, for the
conditions of the above problem, would require 48.5 ft.
in the bend, while by using 6-in. pipe, four branches each
35 ft. long would be used.
COLD SPRING RELIEVES STRAINS ON HOT PIPE
Another method frequently used for increasing the
amount of expansion which can be cared for by a bend or by
the straight length at a 90-deg. turn, is the cold spring when
installing the piping system. If the run of pipe be cut
short by, say, one-half the amount of the expansion at
maximum temperature, and the pipe be sprung by this
amount when erecting cold so as to put the pipe under
tension, the part of the pipe which takes up the expan-
sion may then care for double the amount which it could
if no cold springing were used. The amount of cold spring.
may even be made equal to the entire amount of expansion.
if the arrangement of the piping system will permit. Thus,
the joints and fittings will be put under a tension when
cold and with no steam pressure on the system, and will
be relieved of all tension due to springing of the pipe
when the system is in use and the steam pressure at the
maximum. This method of cold spring must be used,
however, with judgment, and it must be remembered that
it is impossible to stretch pipe lengthwise when erecting it.
The cold spring must be taken up by the bending of pipe
either where the pipe run changes direction or by the
insertion of expansion bends.
43
EXPANSION JOINTS
Of these one form has a sleeve sliding in a stuffing box;
the other form takes up the movement by the spring of a
diaphragm.
When installing a slip joint it should be remembered
that the sleeve must be at its extreme outer permissible
position when the joint is installed, since the sleeve moves
inward in the stuffing box as the pipe expands.
Brass is used in the construction of a simple form of
expansion joint made in sizes for pipe from 2 to 3 in.,

3
PACKING
PACKING
FIG. 33.
PLANTS:
(B)
(c)
TYPES OF EXPANSION JOINTS FOR USE IN POWER
A, SIMPLE EXPANSION JOINT; B, CORRUGATED
JOINT SUITABLE FOR HIGH PRESSURES; C, GUIDED EXPAN-
SION JOINT
for pressures up to 125 lb. and with 2 to 3-in. traverse.
The ends are screwed and stuffing box fitted with a gland
nut. Special joints may be had for sizes from 34 in. to
21½ in. with traverse from 4 in. to 12 in.
Iron-body expansion joints with brass sleeves have the
ends either screwed or flanged. They are for 2-in. to
12-in. pipe with standard traverse running from 21½ up to
8 in. and special with traverse from 6 to 18 in. The
glands for stuffing boxes are tightened by stud bolts, three
being used on the smaller sizes and four on the larger.
Expansion joints of two types have the expansion cared
for by the elasticity of a corrugated copper pipe. The
ends of the pipe are turned out over plain flanges and butt
against the companion flange or gasket to make the joint.
44
For low pressures up to 20 lb., no reinforcement of the
copper is needed, but for high pressures, up to 160 lb., an
inner slip tube of hard composition is used, having tri-
angular equalizing rings of cast iron to fit into the corruga-
tions of the copper tube and equalize the play so that each
corrugation takes its share of the travel. For very high
pressures, reinforcing rings are placed in the outside
grooves of the copper to assist in carrying the steam pres-
sure and in equalizing the movement.
In the guided expansion joint the outer sleeve is ma-
chined on the inside surface and the flanges which travel
in it are machined on their peripheries, thus giving perfect.
alinement to the bronze slip tube, relieving the packing
of wear and avoiding sticking, or sagging of the line at
the joint.
PURPOSES AND METHODS OF ANCHORING PIPE
Piping is anchored for two purposes-crosswise an-
choring to prevent or lessen vibration, and lengthwise.
anchoring to insure the permanent position of the pipe at
some one or more points, and to throw the expansion in
the direction desired. Various forms of anchors are
shown in Fig. 34. The anchor must be firmly fastened
to some rigid part of the structure, such as a beam or col-
umn, and for preventing endwise movement should be of
such form as to permit sidewise motion of the pipe in all
directions; for stopping vibration, the anchor should pre-
vent sidewise motion in the direction in which the vibra-
tion takes place, but should permit endwise motion of the
pipe due to expansion. The anchor for vibration should
be placed at the point of the greatest amplitude of the
vibration, and should usually be accompanied by the intro-
duction of long radius bends at any nearby points where
the pipe changes direction, and by the installation of a
receiver of large volume at the end of the pipe run.
In installing anchors and supports for piping, it is
necessary to allow for the expansion of cross branches so
that there may be sufficient length to take up the expansion
by the spring of the pipe. An example will illustrate this.
Referring to Fig. 32, the main line is anchored close to
the tee where the 5-in. branch is taken off, and it is in-
tended that the expansion of the branch shall be taken
45
This is 30 ft.
Fig. 29 show
The
up to the right, away from the main line.
in length of 5-in. pipe, and the curves of
that this will call for an expansion of 0.75 in.
anchor on the second run of 2-in. pipe must, therefore,
be placed far enough from the end of the 5-in. line so that
the spring of the 2-in. pipe beyond the anchor may take


(A)
(B)
(C)
(D)

(E)
下
​(F)
(G)
(H)
FIG. 31.
TYPES OF ANCHORING FOR PIPES: A AND B, SUS-
PENSION ANCHORS; C, ANCHOR TEE; D, WALL SUPPORT AND
ANCHOR E, ANCHOR TO COLUMN; F AND G, ANCHORS TO
RISERS; H, ANCHOR TO HORIZONTAL BEAM
care of this 0.75-in. expansion. From the diagram, Fig.
29, it is seen that to take care of 0.75-in. expansion will
require 9.5 ft. of 2-in. pipe, so that the anchor must be
placed 9.5 ft. from the tee where the 5-in. pipe connects
to the 2-in. The supporting saddle on the 5-in. pipe must
be placed sufficiently to the left of this joint to permit of
the 5-in. pipe taking up the expansion due to the 9.5
ft. of 2-in. pipe between the joint and the anchor. The
curves show that 10 ft. of 2-in. pipe will have an expan-
sion of 0.25 in., and that to take up this expansion will
require 6 ft. of 5-in. pipe; therefore the supporting saddle
must be placed 6 ft. from the tee. It is intended, of course,
that the expansion of the 4-in. line will be taken up in the
bend where it changes direction.
Fixed anchorage in the steam system is usually re-
quired adjacent to the point where the turbine lead comes
off the header. In the majority of cases anchorage by
attachment to the building structure in a rigid manner
is called for at this point. The balance of the system is
supported at various points, either in a flexible way per-
46
FIG. 35. LOCATION OF PIPING SUPPORTS IN THE SHERMAN
CREEK STATION
TYPICAL FIRST FLOOR
Boiler HeADER
I
I
Second FLOOR
Boiler Headers
DIVISION WALL
が
​SECOND FLOOR
Boiler HeaDERS
<-BOILER HEADER
~BOILER HEADERS
S
the main steam piping in the Sherman Creek Station.
roller supports. Figure 35 shows the piping supports for
mitting motion in the direction desired, or by means of

TURBINE N98 LEAD
~~TURBINE NOT LEAD
~~Turbine N°6 LEAD
JO TURBINE NO3 LEAD
"TURBINE NO A LEAD
Z-TURBINE NP 3 LEAD
~Turbine Nº 2 Lead
TURBINE NI LEAD
LETTER A Indicates ANCHOR
Letter R INDICATES ROLLER,
LETTER H INDICATES RIGED HANGER
LETTER 9 INDICATES Spring Hanger
1
MH
CHAPTER V
MATERIALS USED FOR PIPING
ILD STEEL, wrought iron, cast iron, brass and
copper are the materials commonly employed in the
manufacture of pipe for power and heating service.
Formerly wrought iron was favored for the best class
of work, on account of its greater ductility and resistance
to corrosion. Improvements in the manufacture of steel
have now made it satisfactory for general piping work, and
it is now used extensively.
Steel for pipes is commonly made by the open-hearth
or Bessemer process, giving a tough and strong quality of
metal, similar to boiler plate. It should have an ultimate.
tensile strength of about 60,000 lb. per square inch.
FACTORS IN PIPE DURABILITY
Physical properties of pipe are often as important to
its life as its resistance to corrosion. This is especially the
case in high pressure steam, compressed air, ammonia and
gas lines.
Life of all pipe must depend largely on service condi-
tions. No matter how well any certain grade of pipe may
resist rust, its life may be short if it is liable to crystalli-
zation and fracture from vibration, expansion, shocks and
other stresses, or if the welds are not uniformly reliable,
or the threads or joints lack strength.
Steel and wrought iron pipe is usually graded as
"Standard," "Extra Heavy" and "Double Extra Heavy,"
the thickness and weights increasing progressively. Vari-
ation in weight should not be more than 5 per cent from
the specified standards.
Pipes up to 12 in. in size are designated by the nominal
inside diameters; those above 12 in. are specified by their
actual outside diameters. No established grading exists.
for these larger pipes. For ordinary service, they are
made ¾ in. thick; for heavy service, the 14 and 15-in.
sizes are in. thick; the 16, 18, 20 and 22-in. are 5% in.
thick; and the 2-1-in. pipe is 1 in. thick. All pipes larger
3
9
IC
16
48
than 12 in., and all sizes of extra heavy and double extra
heavy pipe, are furnished, unless otherwise ordered, with
plain ends, without threads or couplings. Smaller sizes
of standard pipe are threaded and coupled. Changes in
thickness and weight of the various grades are made by
varying the inside diameter only. The outside diameter
remains constant, so that any grade of pipe may be joined
by any grade of fitting, flange, coupling or valve. Dimen-



:623″
54
24"
··840"
STANDARD
-.840"
EXTRA HEAVY
:840"
DOUBLE EXTRA
HEAVY
FIG. 36.
DIMENSIONS OF A 12-IN. STEEL OR
WROUGHT IRON PIPE
sions of 1/2-in. steel or wrought-iron pipe are shown here.
Standard-weight is commonly used for heating work,
exhaust lines and all pressures below 100 lb. per square
inch, but for pressure from 100 to 200 lb., extra heavy pipe
should be employed. When particularly exposed to cor-
rosion, it is well to use extra-heavy pipe. This applies to
blowoff connections to boilers, feed lines, sealed returns,
underground drip piping, etc., and all lines that are to run
in places that are not easily accessible.
Tests show the actual bursting strength of mild steel
pipe from 2 to 6 in. in diameter to range from 5000
to 3000 lb. per square inch and it is commonly subjected
to a hydrostatic pressure at the mills of 500 to 1000 lb.
Extra heavy and double extra heavy pipe is tested to a
maximum pressure of 1500 lb. Special hydraulic pipe,
for service on lines requiring the highest possible grade.
of material and workmanship, is bored from solid forgings
and is made to order for pressures up to 10,000 lb. per
square inch.
49
WROUGHT IRON PIPING
Genuine wrought iron possesses many qualities which
are desirable for a piping material. It is soft, and tough,
is easily welded, and resists corrosion to a large degree.
It has an ultimate tensile strength of about 45,000 lb.
per square inch.
Iron pipe is rough in appearance and the scale on it
is heavy, whereas on steel the scale is light and has the
appearance of small blisters or bubbles, underneath which
the surface is smooth and somewhat white. When flattened,
steel pipe seldom breaks; but if a fracture occurs, it will
be noticed that the grain of the metal is extremely fine.
Iron pipe, when subjected to this test, readily breaks and
shows a coarse fracture, due to the long fiber of this
material.
The term wrought pipe is often used indiscrimi-
nately to designate all butt-or lap-welded pipe, whether
made of wrought iron or steel. If requirements demand
the use of either steel or iron, it should be distinctly stated
in the specifications.
Dimensions and weights of standard grade pipe are
furnished in Table III.
"Galvanized-iron" pipe is ordinary wrought pipe with
a galvanizing coating. The grades are the same as those
for wrought pipe, although the double extra heavy is sel-
dom made. Galvanized pipe may be used for cold water
on lines of comparatively small size, standard grade being
sufficiently heavy for most purposes. When employed on
blowoff lines, the extra-heavy grade is specified.
CAST IRON FOR PIPING
Because of its comparatively high corrosion-resisting
qualities, it is advisable to use cast iron instead of wrought
iron for main steam pipes and branches where acids are
used, or where the pipes must be placed underground or
submerged. It is more durable than steel or wrought iron
pipe, but its first cost is greater for the ordinary sizes
required in a pressure line or in a distributing system.
Due to its low elasticity and rather uncertain tensile
50
strength, commercial cast-iron pipe is not suitable for
lines subject to the strains of expansion, contraction and
vibration, unless it is very heavy weight.
Cast-iron piping is not suitable for superheated steam.
service, or for temperatures above 575 deg. F. It is ex-
tensively employed for cold water on lines of compara-
tively large size, 4 in. and above, and is often used for
hot water in these sizes owing to the high cost of brass.
TABLE VII. STANDARD THICKNESSES AND WEIGHTS OF
CAST-IRON PIPE

10
160040
8
Nominal Inside
Diameter - In.
0000mickness
Inches
Clase A
100 Ft. Head
43 Lb. Pressure
Class B
200 Ft. Head
86 Lb. Pressure
Class C
300 Ft. Head
130 Lb. Pressure
Pounds per
Ft.
Length
-Thickness
Inches
Pounds per
Ft.
Length
Thickness
Inches
Pounds per
Ft.
Length
Thickness
Inchee
Clase D
400 Ft. Head
173 Lb. Pressure
Pounds per
Ft.
Length
0.39
14.5
176 0.42
16.2
194
0.45
17.1
206 0.48
18.0
216
0.42
20.0
240 0.45
21.7
260 0.48
23.3
280 0.52
26.0
300
0.44
30.8
370 0.48
33.3
400 0.51
35.8
430 0.55
38.3
460
0.46
42.9
616 0.51
47.5
570 0.56
62.1
625
0.60
66.8
670
0.50
67.1
686 0.67
63.8
765 0.62
70.8
850
0.68
76.7
920
12
0.54
72.5
870 0.62
82.1
985
0.68
91.7
14
0.67
89.6
16
0.60
108.3
18
0.64 129.2
20
0.67 150.0
24
0.76
204.2
30
0.88
291.7
1,076 0.66
1,300 0.70 125.0
1,550 0.75 150.0
1,800 0.80 175.0
2,450 0.89
233.0
3,500 1.03 333.3
1,100
0.75
100.0
1,200
102.5
1,230 0.74 116.7
1,400
0.82
129.2
1,660
1,500 0.80 143.8
1,725
0.89
158.3
1,900
1,800 0.87
175.0
2,100
0.96
191.7
2,300
2,100 0.92
208.3
2,500
1.03
229.3
2,750
2,800 1.04 279.2
3,360
1.16
306.7
3,6
,680
4,000
1.20 400.0
4,800
1.37
450.0
36
0.99
391.7
4,700 1.15
454.2
42
1.10
612.6
6
,150
5,9
5,400
450 1.36
545.8
6,550
1.58
625.0
7,500
48
1.26
666.7
54 1.36
800.0
1.28
8,000 1.42
9,600 1.65
591.7
7,100 1.54
716.7
8,600
1.78
825.0 9,900
760.0
9,000 1.71
908.3
10,
900
1.96
933.3 11,200 1.90
1141.7
13,700
2.23
1341.7
60
72
1.39
1.62
916.7 11,000 1.67
84 1.72
1281.9 15,380 1.95
1635.8
1104.2
1547.3
19,630 2.23 2104.1
13,250 2.00
18,570 2.39 1904.3
25,250
}
1341.7
16,100
2.38
1683.3
1050.012,800
16,100
19,000
22,850
The above weights are for 12-ft. lengtha including standard sockets.
Cast-iron pipe should be made of a soft and tough
quality of iron and should be subjected to a test pressure
of at least twice the working pressure. The ultimate
tensile strength may be taken as 20,000 lb. per square inch
and the factor of safety at 1212.
Cast-iron pipe is made in a variety of thicknesses and
weights, and manufacturers commonly tabulate the grades.
for various pressures or heads. Thicknesses and weights
for standard pipe up to 173 lb. pressure are furnished in
Table VII.
Thickness of cast-iron pipe is found by the following
formula which was adopted by the American Water Works
Association, and now used generally as the manufacturers'
standard throughout the United States:
(PP¹) r
T 0.25 +
3300
51
In which T= thickness in inches; P=maximum
static pressure in pounds per square inch for which the
pipe was designated; P¹ allowance made for water ram,
and r
radius in inches. This provides a large factor
of safety to cover inequalities of the castings, strains placed
on the pipe from other causes than water pressure, and to
give sufficient thickness to insure the pipe against breakage
in shipping and laying. For ordinary waterworks con-
ditions for pipes from 42 to 60 in. diameter, 70 lb. per
square inch is enough for P¹, but for smaller pipe, Brackett
allows the following values:
10 to 3
120
Dia. of pipe in. 36 30 24 20 16 12
P¹ lb. per sq. in.=75 80
75 80 85 90 100 110
Rule for calculating the weight of cast-iron pipe is:
W = 2.45 (D² — d²)
In which W weight per lineal foot; D= outside diam-
eter in inches; d= inside diameter in inches; 2.45=
constant.
USES FOR BRASS PIPING
Brass piping is generally employed for condenser tubes,
feed water between pumps and boilers, and general hot
water supply lines, on account of its resistance to corrosion
and pitting, and its flexibility. It is extensively used for
steam coils in water tanks or water coils in steam tanks
for heating feed water for boilers, etc. Small sizes of brass
pipe are employed for oil connections in machinery, as they
can be easily bent, and when polished give a neat appear-
ance.
For steam work brass pipe is made in all standard
iron pipe sizes up to 6 in. in diameter. It has a thickness
nearly equal to that of standard wrought iron pipe, hence
is of sufficient thickness to permit a similar thread. Stand-
ard lengths are 12 ft., and come without threads. Table
VIII gives the size and weights of brass and copper pipe.
Thin brass tubing commonly employed for ornamental
work, hand-rails, etc., is not of the proper size to take the
standard pipe thread and is too thin for pressure work.
Brass castings average about 18,000 lb. per square inch
ultimate tensile strength. For steam or valve metal, brass
contains about 85 per cent copper, 7 per cent tin, 5 per
cent zinc and 3 per cent lead.
52
COPPER PIPING
Copper pipe may be seamless drawn (up to 8 in.
diameter) or may be brazed up from sheets. It is less
used than formerly, since the ductility and flexibility of
copper are found to be impaired by high temperature.
At a temperature of 360 deg. F., its strength is reduced 15
per cent, and for this reason it should never be used for
high steam pressures and temperatures unless reinforced.
Seamless copper pipe of iron pipe sizes may be em-
ployed for spring bends for main steam lines; sizes less
than 4 in. may be bent cold.
TABLE VIII: SIZES AND WEIGHTS OF IRON PIPE SIZE OF
BRASS AND COPPER TUBES

Diam..In.
Wt. per Ft.
Lb.
Diam., In.
wt. per Ft.
Lb.
Nominal
Size, Out-
In-
Brass
Copper
Nominal
Size
Out-
In.
side Bide
In.
side
In-
side
Brase Copper
1/8
0.405 0.281
0.246
0.259
3
3.500
3.062
8.314 8.74
1/4
.540 .375
.437
.459
3 1/2
4.000 3.500
10.85
11.41
3/8
.675 .494
.612
.644
4
4.500
4.000 12.29
12.93
1/2
.840 .626
.911
.958
4 1/2
5.000
4.500 13.74
14.44
1
1.050 .822
1.315 1.062
1.235
1.298
5
1.740 1.829
6
5.563
6.625 6.125
5.062 15.40
16.19
18.44
19.39
1 1/4
1.660 1.368
2.5572.698
7
1 1/2
1.900 1.600
3.037 3.193
8
2
2.375 2.062
4.017 4.224
9
2 1/2
2.875 2.500 5.830 6.130 10
7.625
7.062 23.92
8.625 8.000 30.06
9.625 8.937 36.94 38.84
10.750 10.019 43.91 46.17
26.15
31.60
Sheet copper possesses a tensile strength of about
35,000 lb. per square inch. Thickness of copper steam
pipes may be determined from the formula:
t= 0.0001 d X p + 0.125
in which t-thickness in inches; d=internal diameter;
p= pressure in pounds per square inch, and 0.125 is a
constant.
Copper pipe sizes are similar to those for brass and are
given in Table VIII.
TYPES OF PIPING
Manufacture of pipe can be divided into four general
classifications-welded, riveted, cast and seamless. Welded
pipe may be divided into two sub-classes-lap and butt.
Both are made from strips of rolled iron or steel, com-
mercially called skelp. Butt-welded pipe is commonly
made in sizes from 1 to 2 in., lap-welded pipe from 2 to
72 in.
53
LAP-WELDED PIPE
In the case of the lap weld, the edges of the skelp are
scarfed and it is bent in tubular form so as to lap one
edge over the other; then when brought to a welding heat,
is passed through a circular groove in the welding rolls
with a supporting cast-iron mandrel on the inside, pro-
ducing pressure upon the overlapped scarfed edges, welding
them and reducing the thickness of the lap to the uniform
TABLE IX. WEIGHTS AND BURSTING PRESSURES OF LARGE
LAP-WELDED STEEL PIPE

Inside
Diameter
Thickness Weight
Approx. Bursting
Per Foot
Pressure
Inches
Inches
Pounds
Lb. Per Sq. In.
12
0.187
25.8
1562
14
0.187
30.0
1339
16
0.187
34.2
1172
18
0.187
38.4
1041
20
0.187
42.6
937
22
0.187
46.8
852
24
0.187
51.0
781
30
0.187
64.0
625
36
0.250
102.0
694
40
0.312
142.0
781
42
0.375
179.0
892
88888
48
0.375
204.0
781
54
0.500
306.0
926
60
0.625
426.0
1040
66
0.750
563.0
1132
72
1.000
822.0
1388
gage of the rolled skelp. The strength of a lap weld is
approximately 92 per cent of that of the plate which it
joins. Tests on commercial lap-welded pipe have given
an average bursting strength of 52,000 lb. per square inch
for steel, and 31,000 lb. per square inch for wrought iron.
Table IX gives the weights and bursting pressures of large
lap welded steel pipe. The factor of safety for steam pip-
ing should not be less than 6. Lap-welded pipe is espe-
cially suited for high-pressure steam and water lines and
vacuum service.
BUTT-WELDED PIPE
In the butt-welded pipe, the square edges of the rolled
strip are brought together by pressure when at a welding
heat, and welded when the strip is drawn through a circu-
lar die, without the use of an interior support or mandrel.
54
As a result of numerous tests, the strength of a butt
weld has been found to be about 73 per cent of that of
the plate which it joins. The average bursting strength
for butt-welded steel pipe is about 41,000 lb. per square
inch, and that of butt-welded wrought iron pipe is ap-
proximately 29,000 lb. per square inch.
TABLE X. DATA ON SPIRAL RIVETED PIPE

Thickness, B. W. Gage
Nominal
Size,
No. 20. No. 18. No. 16. No. 14. No. 12.
No. 10.
In.
Bursting Strength, Lb. per Sq. In.
3
1325
1860
4
1000
1390
1845
5
795
1100
1480
6
930
1220
1580
2060
7
790
1060
1340
1780
8
690
945
1180
1540
9
820
1040
1380
10
740
945
1024
11
670
860
1120
12
615
790
1025
1265
13
570
730
950
1165
14
530
675
890
1090
15
630
825
1015
16
590
770
950
18
525
690
850
20
470
620
760
22
430
565
695
24
395
515
636
26
475
580
28
30
44C
545
410
510
Butt-welded pipe is not suitable for steam or water
under high pressure, or for pipes which must be bent. It
is adapted for gas service.
DRAWN PIPE
Referring to the manufacture of drawn-steel pipe, we
may divide it into four different processes:
First, the punching and rolling; second, the plate-
cupping process; third, the cast-hollow-billet process, and
fourth, the piercing process, which is by far the most
important of the seamless processes.
Seamless piping is well adapted for boiler tubes, coils,
cylinders, piston rods and exhaust lines.
Boiler tubes were formerly made of charcoal iron, but
due to improved process of manufacture, the solid-drawn
55
seamless steel boiler tubes are now common, possessing
the same degree of ductility with a great tensile strength.
RIVETED PIPING
Straight-riveted pipe and spiral-riveted pipe are fur-
nished in lengths up to 40 ft. with pressed or forged-steel
flanges riveted to the ends. It is employed extensively in
noncondensing power plant work for exhaust-steam mains,
condenser service, large drains, etc., but should never be
used for steam, feed water or similar high-pressure work.
It is also suitable for water supply lines, brine circulation
and suction lines. Spiral-riveted pipe, because of its con-
struction, is stronger than straight-riveted pipe of equal
size, thickness and quality. The single seam in this pipe,
being continuous and helical from end to end, stiffens it
throughout its length.
It is usually made in different gages up to 1/4 in.
thickness, and furnished in any length desired up to 40
ft. for asphalt-coated pipe, and 20 ft. for galvanized pipe.
Data on spiral-riveted pipe are given in Table X.
For exhaust steam, suction, condenser work, compressed
air, etc., the galvanized pipe is preferable; the asphalt-
covered pipe is recommended for water supply lines,
dredging work, hydro-electric service, etc.
CHAPTER VI
CORROSION OF PIPING AND ITS PREVENTION
IN THE process of corrosion of iron and steel, the first
IN
step is the solution of the iron in water. When water
comes in contact with iron, a small amount of iron goes
into solution, and, if the water is pure, the action ceases
in a comparatively short time when the solution has be--
come saturated. If, however, the water contains oxygen
in solution, this unites with the iron in the form of ferrous
hydrate to form insoluble ferric hydrate, which is ordi-
narily known as rust. The action goes on indefinitely as
long as there is oxygen present, but may be stopped at any
time by simply shutting off the supply of air.
DEACTIVATING WATER
Air which can be held in solution in water varies in
amount inversely with the temperature and pressure, being
zero at the boiling point. An obvious method, then, of
preventing corrosion would be to rid the water of air by
heating it. If the water is heated to a temperature just
below the boiling point and then cooled, if necessary, in
the absence of air, we have a supply that is free from air
and cannot, therefore, cause corrosion. This principle is
practically applied in several devices. One consists of
three sections, one above the other; the lower section is
an exchanger in which the cold water entering is heated
to about 140 deg., depending, of course, on its initial tem-
perature, by the hot water leaving. The middle section
is a thermostatically controlled instantaneous heater, in
which the temperature is further raised to about 207 deg.
by a steam jet. At this temperature the water enters the
top section where it spills over a series of trays, thus
exposing a large surface and allowing the dissolved gases
to escape to the atmosphere. The deactivated water then
passes through the exchanger and leaves the apparatus.
at about 100 deg.
Another method of accomplishing the same result is
to deliver hot water from a heater to a large tank that
57
is completely filled with scrap metal. This metal will
be corroded instead of that encountered later on in the
system, thus saving the latter. The rate of the chemical
activity taking place varies directly with the tempera-
ture so that it is advisable to have the water as hot as
possible. At 50 deg., complete deactivation may require
as much as 24 hr., whereas at 210 deg., the desired result
may be effected in 2 min. By providing a tank of suf-
ficient capacity, the water will leave the tank almost inca-
pable of further corrosive action. Water leaving this tank
will contain a considerable quantity of rust in suspension.
which should be filtered out before it is used.
In this apparatus the water does exactly what it would
otherwise do in the piping of the system, but instead of
destroying expensive and inaccessible pipe, it makes rust
out of metal that can easily be renewed for a few cents
a pound.
Where it is impractical to heat the water, as in city
supplies, dissolved air may be removed by spraying it into
a vacuum. Water sprayed into a vacuum of 28 in. will
have its air content reduced by about 90 per cent.
PROTECTION FOR INSIDE OF PIPE
Protection of the inside of piping may be effected by
the application of some kind of coating, such as well
refined asphalt or coal tar, concrete or neat cement.
Finish and structure of the metal itself has a good deal
to do with the rate of corrosive deterioration. The metal
should be as homogeneous and as free from strain as pos-
sible to limit electrolytic action. For this purpose, wrought
iron or steel pipes should be thoroughly worked in the
process of manufacture and should be well annealed. Mill
scale or magnetic oxide is effective in accelerating the
action where oxygen is present.
External corrosion, as of oil or water pipes laid under-
ground, can be effectively checked by the application of a
metallic or non-metallic coating. Underground corrosion.
may be accelerated by the presence of certain salts or acids
in the soil and by the ready access of free oxygen, either
by direct circulation or by underground waters. The action
is greatly increased by the contact of the metal with any
58
materials which tend to intensify galvanic action, such as
cinders. It is important that water be excluded from
contact with the metal, and to this end the trench should
be well drained.
Waterproof coating applied to the pipe has been found
effective in reducing deterioration. This coating may
be applied either at the shop or in the field, but the former
is usually preferable, as the pipe surface can more readily
be cleaned of scale or rust.
COATING PIPES TO PREVENT EXTERNAL CORROSION
One large pipe manufacturer uses the following pro-
cedure for coating pipes for this service. The pipe is first.
dipped in an acid pickling solution to remove all scale,
and then in an alkaline washing solution. It is then heated
to about 212 deg. until perfectly dry, when it is dipped into
a bath of hot asphalt, coal tar, or mineral rubber com-
pound and allowed to remain there sufficiently long for
the pipe to acquire a temperature of 300 deg., the tem-
perature of the bath. The pipe is then raised on end and
the excess coating allowed to drain off. When it is cool, a
fabric saturated with the coating material is wound around
the pipe, after which the surface is covered with a thin
layer of Portland cement. For extreme conditions, a
number of layers of coating may be employed. In the
field the pipe is laid in the trench between forms and
covered with several inches of concrete, after the joints
have been covered with tar or asphalt. The concrete should
be sufficiently fluid to fill the space under the pipe com-
pletely. If the forms are removed when the cement has
set, the whole should be given a coat of tar before the
trench is filled in.
CHAPTER VII
RADIATION LOSSES FROM PIPES
T HAS been experimentally determined that each square
foot of bare pipe surface will radiate about 3 B.t.u. per
hr. for each deg. F. difference between the temperatures.
of the steam and the outside air, the exact amount varying
with the velocity and humidity of the air. If, in any
particular case, the essential conditions are known, the
heat loss can be estimated in terms of dollars and cents.
It will be necessary to determine the square feet of ex-
posed pipe surface; the average temperature of the sur-
rounding air subtracted from the temperature of the steam,
will give the temperature difference. Conditions of opera-
tion of the plant will approximately determine the number
of hours which steam will be in the pipe line during
a period of one year. These factors will give the total
B.t.u.'s lost during the year, and this amount divided by
970.4 will give the number of pounds of steam from and
at 212 deg. equivalent to this loss. The evaporation per
pound of coal and the cost of coal per ton (including cost
of handling it and ashes) being known, the money value
of the loss is easily derived.
Expressed in a formula:
Loss per year due to steam condensed
3 A (t-t) NX C
970.4 × 2000 E
In which A sq. ft. of pipe surface exposed; t tempera-
ture deg. F. of steam; t, average temperature deg. F.
of surrounding air; N= number of hours per year steam
is in the pipe line; Eevaporation from and at 212 deg.
F. per lb. of coal; C cost of coal and handling, per ton
of 2000 lb. Latest practice relates the cost of covering
to the resultant saving of condensation; that is, the initial
charge plus depreciation and interest on the investment
for pipe covering should not exceed the saving which cor-
responds to the decrease in condensation losses. In gen-
eral, however, conditions are such that the saving outweighs
60
by a large margin the cost of pipe covering of proper
thickness.
MATERIALS FOR COVERING PIPES
Pipe covering may be either "sectional," that is molded
to the shape of the pipe and attached by means of bands;

Q.95
0:30
0.5
т
Na VIII Salt-Mo Expanded
Na
JM Wool Felt
\No.17 JM Eureka
No. X Carey Duplex
No XIX Plastic 65% Magnesion
Na XI Sall-Mo Wool Felt
0.75
$0.70
0.65
$390
HEAT LOSS PER DEGREE TEMPERATURE DIFFERENCE PER SQUARE FOOT PER HOUR-B.Z.U.
330
Q50
60
a55
0.60
Ha! JIM Asbestos Fire Felt
Nolll ‍J-M_Vitribestos
No. XXY Sall- Mo Air Cell
No. I J.M Molded
No. XVII J-M Air Cell
No.1 JM Indented
No LX Carey Serrated
NOX
No. XX
NO. VI
0.45
No. XII
40
I 035
030
'No. XIII J-M Asbestocel
"No. VIII Concey Carocel
Na No. VII
No IJ-M 85% Magnesial
"NaXT Corey 85% Hoonesia
No. X Nonpareil High Pressure
No. X JM Asbesto Sponge Felted
암
​50
150
200 250 300
100
350 400 450
TEMPERATURE DIFFERENCE. DEGREES FAHRENHEIT
(PIPE TEMP - ROOM TEMP)
500
FIG. 37.
SUMMARY OF RESULTS OF SINGLE THICKNESS
COVERING
or "plastic," which is mixed in the form of mortar, and
placed on the pipe in layers. Sectional covering is usually
made in 3-ft. lengths.
Asbestos, diatomaceous earth and magnesia are the
insulating substances most commonly used, because of
61
their heat-resisting qualities, but cork, hair felt and min-
eral wool are also poor conductors of heat. Standard cov-
ering consists of 85 per cent of carbonate of magnesia
mixed with 15 per cent of asbestos or its equivalent.
For high-pressure pipes from 2 to 8 in. in diameter,
the covering should be from 12 to 21½ in., the thickness
varying according to size. A thickness of 3 in. is used on
lines over 8 in. in diameter. For smaller lines and low-
pressure piping 1 in. is sufficient. In low-pressure steam
and hot water lines, wool felt in combination with asbestos
has been found to give satisfactory service. Other forms
are constructed with layers of corrugated asbestos paper
using the principle that still air is a poor conductor of heat.
L. B. McMillan, in the Journal of the A. S. M. E.,
offers the results graphically recorded in Fig. 37, which
were derived from the extensive conductivity tests with
various forms of commercial covering. This chart shows.
the heat loss in B.t.u. per degree temperature difference
per sq. ft. per hr. of some of the coverings which are
briefly described herewith. Statements as to whether the
coverings were recommended for high or low pressure or
superheated steam pipe were furnished by the manufac-
turer, and are not conclusions drawn from the tests. The
weight per foot in each case is the average weight per
lineal foot of 5-in.. pipe covering, and the thickness given.
is the average thickness.
1: J-M 85 Per Cent Magnesia. Molded sectional
covering for high pressure steam pipes; 85 per cent by
weight of magnesium carbonate and the remainder prin-
cipally asbestos fiber. Weight per foot, 2.92 lb. and thick-
ness 1.08 in.
2: J-M Indented. Layers of asbestos felt with inden-
tations, about 1/4 in. in diameter and 1 in. deep, spaced
very close to each other in staggered rows. For pipes con-
taining high pressure steam. Weight per foot, 3.46 lb.
and thickness 1.12 in.
3: J-M Vitribestos. Asbestos air cell covering made.
of alternate layers of smooth and corrugated vitrified as-
bestos sheets. Corrugations about 1/4 in. deep and run
lengthwise of the pipe. For use on high-pressure and
superheated steam pipes and for stack liners, etc. Weight
per foot 4.05 lb. and thickness 0.96 in.
62
4:
J-M Eureka. For low pressure steam and hot
water pipes. Made of 1/4 in. of asbestos felt on the inside
of the section and the balance of alternate layers of
asbestos and wool felt. Weight, 4.60 lb. per ft., and is
1.04 in. thick.
5: J-M Molded Asbestos. Molded sectional covering
for use on low and medium pressure steam pipes. Made
of asbestos fiber and other fireproof material. Weight
per
ft. 5.53 lb. and thickness is 1.25 in.
6: J-M Wool Felt. A sectional covering made of
layers of wool felt with an interlining of two layers of
asbestos paper. May be used on low pressure steam and
hot water pipes. Weight per ft. 2.59 lb. and thickness
1.10 in.
7: Sall-Mo Expanded. A covering for use on high and
low pressure steam pipes. Made of eight layers of material,
each consisting of a smooth and a corrugated piece of
asbestos paper, the corrugations being crushed down to
form small longitudinal air spaces. Weight 3.47 lb. per
ft. and thickness 1.07 in.
8: Carey Carocel. Composed of plain and corrugated
asbestos paper firmly bound together. Corrugations are
approximately 8 in. deep and run lengthwise of the pipe.
For use on medium and low-pressure steam pipes. Weight
3.06 lb. per ft. and thickness 0.99 in.
9: Carey Serrated. For high pressure steam pipes.
Composed of successive layers of heavy asbestos felt having
closely spaced indentations. Weight 5.66 lb. per ft. and
thickness 1.00 in.
10: Carey Duplex. For low pressure steam and hot
water pipes. Alternate layers of plain wool felt and cor-
rugated asbestos paper firmly bound together. Corruga-
tions run lengthwise and make air cells approximately 14
in. deep. Weighs 1.79 lb. per ft. and is 0.96 in. thick.
11: Carey 85 Per Cent Magnesia. For high pressure
steam and similar in composition to No. 1. Weight per
foot 2.74 lb. and thickness 1.10 in.
12: Sall-Mo Wool Felt. Similar to No. 6, except
without interlining asbestos paper. For low pressure steam
and hot water pipes. Weight per foot 3.73 lb. and thick-
ness 1.01 in.
63
PROPER THICKNESS
PROPER THICKNESS
THICKA
13: Nonpareil High Pressure. Molded sectional cov-
ering consisting mainly of silica in the form of diatomace-
ous earth-the skeletons of microscopic organisms. For
high pressure and superheated steam pipes. Weight 2.96
lb. per ft. and is 1.16 in. thick.


100
300
500°
200
400°
TEMPERATURE DIFFERENCE ºF.
STEAM AT 20 PER 1,000,000 B.T.U.
FLAT
24
12
6
3
1 ½
FLAT
24
12
6
3
فيا
3/4
ROPER THICKNESS,
ری
PROPER THICKNESS
ญ
100.
200. 300° 400° 500*
TEMPERATURE DIFFERENCE °F.
STEAM AT 60 PER 1,000,000 B.T.U.
100
200° 300
TEMPERATURE DIFFERENCE
400°
500
1001
*F.
200*
400° 500
TEMPERATURE DIFFERENCE F
STEAM AT 80 PER 1,000,000 BTU
300*
STEAN AT 40¢ PER 1,000,000 B.T.U
FIG. 38. STANDARD THICKNESSES FOR MAGNESIA
PIPE COVERING
14:
J-M Asbestos Fire Felt. Asbestos fiber loosely
felted together, forming a large number of small air spaces.
For high pressure and superheated steam pipes. Weight
per ft. 3.75 lb. and thickness 0.99 in.
15: J-M Asbestos Sponge Felted. Made from a thin
felt of asbestos fiber and finely ground sponge, forming a
FLAT
24
12
12
314
FLAT
24
12
6
3
ΙΣ
3/4


64
very cellular fabric. Forty-one of these sheets per inch
of thickness; air spaces are formed between the sheets in
addition to those in the felt itself. Specially recommended.
for high pressure and superheated steam pipes. Weight
per ft. 4.04 lb. and thickness 1.16 in.
16: J-M Asbestocel. For medium pressure steam and
heating pipes. Alternate sheets of corrugated and plain
asbestos paper, forming air cells about 1/8 in. deep that run

6
3
List Cost, Dollars Per square Foot
~
3 Pipe
12"
24
17
Flat
Q
FIG. 39.
2
3
4
Thickness of Covering - inches
5
6
COST OF MAGNESIA COVERING UPON WHICH
CURVES IN FIG. 38 ARE CALCULATED
around the pipe. Weight per ft. 1.94 lb. and thickness.
1.10 in.
17: J-M Air Cell. Corrugated and plain sheets of
asbestos paper arranged alternately so as to form air cells
about 1/4 in. deep, running lengthwise of the pipe. For
medium pressure steam and heating pipes. Weight per ft.
1.55 lb. and thickness 1.00 in.
From tests conducted at the Mellon Institute for the
Magnesia Association, the curves shown in Fig. 38 were
drawn and are known as standard thicknesses for mag-
65
nesia pipe covering. They represent the most economical
thicknesses based on costs as shown in Fig. 39.
In Table XI will be found the radiation in B.t.u per
foot length of pipe for various sizes and various thicknesses
of covering, also for bare pipe. These data are based upon
tests made at 160 lb. pressure and are the average per
degree for the temperature difference between 60 deg. air
and the temperature corresponding to 160 lb. pressure.
In Table XII are given efficiencies for magnesia cover-
ing 2 in. thick. It should be noted that efficiencies increase
TABLE XI. RADIATION FROM BARE AND COVERED PIPE

Sise of
Pipe
Bare
of
Thickness of Covering, Inches
Inches
1/2
3/4 1
1-1/4
1-1/2 Pipe
2
.472
.374 .314
.272
.250 1.89
4
.787
.615
.510
.443
.392 3.46
6
1.12
.857 .705
.573
.532 4.95
8
1.40
1.07 .874
.744
.655
6.31
10
1.74 1.32 1.07
.908 .792 7.79
not only with the increase in the size of pipe with the
same temperature difference, but also increase with the
temperature difference for a given size of pipe.
INSULATION FOR COLD PIPES
Insulation is extremely essential to economical refrig-
eration, where low temperatures are maintained by the
expenditure of energy. An increase in the temperature of
the refrigerating medium while flowing through the piping
from the machine to the room or tank where it is to be
utilized calls for an additional out lay of work.
It is important that insulation for cold pipes should not
be readily injured by moisture. One form of insulation
which gives satisfaction in some instances is made by
soaking hair felt in boiling resin and applying to the pipe
while the resin is still hot and the sheets of felt are easily
molded to the shape of the pipe. Heavy twine is employed
66
to fasten the sheets; two layers of the covering are applied,
and after the resin has cooled and set the twine is removed.
Granulated cork molded in a shape similar to the mag-
nesia sectional steam-pipe covering is one of the standard
forms of sectional insulation now on the market. In some
instances, two layers of this are applied, so as to break
joints, and the whole covering is given a coat of rubber
TABLE XII.
EFFICIENCIES FOR MAGNESIA COVERING
2-IN. THICK

Temperature Difference between Steam and Air
Size of
Pipe
50
100
200
300
400
500
Inches
2
81.3 83.3 85.9 88.2 90.2 91.7
3
83.6 85.2
87.7
89.6
91.4 92.9
4
84.8 86.4 88.7
90.5
92.1 93.4
5
85.7 87.2
89.3
91.0 92.5 93.8
6
86.3 87.8
89.8
91.3 92.8 94.0
8
87.0 88.4
90.3
10
87.6 88.9 90.7 92.2
91.8 93.1 94.3
93.4 94.5
cement, making it virtually air-tight. Large brine mains
that are boxed or laid underground can be insulated with
a mixture of ground cork and pitch. The pitch is first
melted, then cork is mixed with it, and the mixture is
then poured over the pipes and well tamped around them.
The proper care of insulation covering plays a large
part in its effectiveness. If, from any cause, it becomes
loose or wet or disconnected, its efficiency is directly af-
fected. It should be thoroughly inspected and repaired
every year; the slight cost for this attention will easily be
covered by the saving resulting from a greater efficiency.
CHAPTER VIII
PIPE CAPACITIES AND FRICTION LOSSES
N ORDER to select the proper size pipe for handling
IN to
water the factors that must be considered are the diam-
eter and length of pipe, condition of the pipe as to the
internal surfaces, and velocity at which the water must
flow. Various rules and formulas have been devised to
embody the results of experiment; but those which, on the
whole, are most convenient and come nearest to repre-
senting the results are the ones proposed by Prof. Schoder
of Cornell University. For new and clean pipes having
smooth surfaces, his equation becomes: the loss of head
in feet per 1000 ft. of pipe = 8.49 V1.86 ÷ d¹.25, and for
old pipes whose surfaces have become roughened by cor-
rosion or accumulation of foreign matter, also for spiral-
riveted pipes, this changes as follows: head lost =
11.17V1.96d1.25. In both equations, V represents the
velocity in feet per second, and d, the diameter of the pipe
in inches.
•
Since this equation is somewhat difficult of solution,
particularly when it is desired to find the diameter of
pipe for a given volume or weight of water to be passed,
and for a given loss of head by friction, the results have
been embodied in the double chart, Fig. 40, from which
readings can be taken direct. The curves on the left-hand
side of the chart give the amount of water in pounds, or
cubic feet, or gallons per minute, for any size pipe, at
any velocity between 1 and 15 ft. per second, which is the
range usually permitted. The velocity per minute will, of
course, be 60 times the velocity per second.
On the right, the chart gives the means of determining,
by a straight edge, any one of the three factors-amount
of water per minute, loss of head per 1000 ft. of pipe, or
diameter of pipe-when the other two factors are known.
As, for instance, if it is desired to know the loss in head
for a 4-in. pipe carrying 20 cu. ft. per minute, the straight
edge is passed through 20 on the cubic feet per minute
scale, and through 4 on the pipe diameter scale, and where
68
it crosses the loss of head scale will give the desired value,
18 ft. for new pipe.
For new and smooth pipes the right-hand pipe diam-
eter scale is used, the left-hand diameter scale being for
LB. PER MINUTE
CU. FT.
PER
MINUTE
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15,

1200 000
1000000
20000
18000
800000
600000
10000
800000
400000
200000
200000
9000
8000
7000
6000
5000
4000
9000
150000
100000
2000
1500
80000
60000
1000
900
50000
800
700
40000
600
30000
18
500
4.50
400
350
20000
300
15000
10000
8000
6000
5000
4000
3000
200
150
100
80
70
60
2000
1500
35
30
22
1000
21
15
800
600
400
300
200
150
70
0000
3
3/4
2
1.5
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
VEL· FT. PER SEC.
FIG. 40. CHART FOR CALCULATING THE FLOW OF
1
69
old or rough pipes. These values apply to straight lengths
of pipe. Where fittings or valves are introduced, extra
loss of head will result. The simplest way to bring in
this loss is by introducing the equivalent length of straight
CU.FT.
PER
MINUTE
20000
16000
150000
100000
80000
80000
10000
70000
9000
8000
60000
7000
50000
6000
40000
5000
OLD ROUGH AND
RIVETEO

NEW CLEAN
0.1

0.15.
0.2
4000
90000
60
60
3000
20000
48
48
2000
15000
36
36
1500
10000
9000
30
8000
1000009
30
7000
800
6000
24
700
5000
24
600
20
4000
45
40
3000
350
300
2000
200
1500
150
1000
900
800
700
400
500
450
400
350
300
35
30
GALLONS PER MINUTE
20
16
16
12
、、
12
10
10
་་
5
5
200
20
1501
DIAMETER OF PIPE IN INCHES
3
15
85
00
2.3
30
LOSS OF HEAD IN FEET PER 1000FT OF PIPE
0.3
04

05
06
000
1.0
15
10
、.
15
30
१ ४
828
150
2
200
2
5.0
300
6
45
1.5
5
.40
1.5
400
30
یا
3
20
2
3/4
314
13
10
WATER IN PIPES AND LOSS OF HEAD BY FRICTION
70
pipe, which from experiments is practically as follows:
ADDED LOSS OF HEAD IN FITTINGS AND VALVES
Kind-
Bends, radius= pipe diameter.
•
Bends, radius 2 to 8 diameters.
Elbow short turn 90 deg..
Elbow short turn 45 deg..
Tees short turn 90 deg..
Gate valves
Globe valves
•
Angle valves
Added Length in
Pipe Diameters
20
10
30
6
60
6
60
90
FLOW OF STEAM IN PIPES
In determining the size of a main for moderately
superheated steam under pressures ranging from 125 to
150 lb. per sq. in., a velocity of from 6000 to 8000 ft. per
min. is generally assumed as standard practice, although
velocities as high as 12,000 ft. per min. are permissible if
the pipe is less than 50 ft. long and free from sharp bends.
In recent installations of large size turbines, the great
volume of steam delivered to the machines necessitates the
use of velocities up to 20,000 ft. per min. For exhaust
lines, 4,000 ft. per min. is a safe working figure.
By means of the chart, Fig. 41, Showing Loss of Pres-
sure When a Given Weight of Steam per Minute Is Deliv-
ered Through a Pipe of Given Size, by Prof. H. V. Car-
penter, and based upon the most commonly accepted
formula* for the flow of steam through pipe, the relation
between size of pipe, average pressure, drop in pressure,
and weight of steam passing in pounds per minute may
be determined. To obtain the pressure drops for lengths
other than 100 ft., multiply by lengths in feet and divide
the product by 100.
Let it be desired to determine number of pounds of
steam which may be delivered per minute by a 100-ft.
fgds
• W=87.5 V ✓ I (1+3.6)
d
Where f=fall in pressure from entrance to exit, in pounds per square inch.
g=means density of steam, in pounds per cubic foot.
d-diam ter of pipe, in inches
L=Length of pipe, in feet.
71
INSIDE DIAMETER OF PIPE, INCHES
2,5 3
6 7 8 9 10 12 14 16 18 20
1,5
2
at
Q15
7777
Q3
Q6
33
LOSS OF PRESSURE
1.0
PER 100 FT. OF PIPE
SQ.IN.
POUNDS PER
length of 5-in. pipe, at a pressure of 150 lb. per sq. in.,
absolute, and with 1 lb. drop.
Follow the 1-lb. drop line (ab) over to the 5-in. pipe
line, then (bc) up to the 150-lb pressure line, and thence
down (cd) to Steam Delivered, Pounds per Minute, ap-
proximately 210 lb.
AVERAGE STEAM PRESSURE
POUNDS PER SQ. IN. ABS,
A
1
T
1
1 1.5 2 3 4 5 6 8 10 15 20 30 40 60801 152 3 4 56 8 1 15 2 3 4 567
FIG. 41.
STEAM DELIVERED
HUNDREDS
THOUSANDS
LBS. PER MIN.
LOSS OF PRESSURE WHEN STEAM IS DELIVERED THROUGH A PIPE

80.
10,0.
72
WET AND SUPERHEATED STEAM
For wet steam we must use in the diagram, instead of
the given pressure, an equivalent pressure, or the pressure
of dry steam, which would have the same density as the
wet steam at the given pressure. In a like manner, for
superheated steam, we must employ the equivalent pressure
DEG. SUPERHEAT~% DRYNESS
238

GIVEN PRESSURE
200
150
100
50
0
50
100
150
200
250
300
EQUIVALENT PRESSURE
FIG. 42. EQUIVALENT PRESSURES OF WET AND
SUPERHEATED STEAM
at which dry steam would have the same density as the
superheated steam at the given pressure.
These corrections may be made by means of the con-
version charts shown in Fig. 42. Wet steam at 150 lb.
pressure and 95 per cent dryness is equivalent to saturated
steam at 160 lb. pressure; steam at a pressure of 150 lb.
and superheated 200 deg. F. is equivalent to approximately
112 lb. pressure saturated steam.
EFFECT OF VALVES AND FITTINGS
Drop in pressure due to the resistance offered by valves.
and fittings is usually allowed for by treating each valve
and fitting as an additional length of pipe which expressed
in inches may be found according to the formula of Briggs,
as follows: For 90 deg. standard elbows divide (the
product of 76 times the diameter of the pipe in inches),
by the sum of (1 plus the quotient of 3.6 divided by the
73
diameter of the pipe inches). For globe valves, use 114
instead of 76.
As a formula:
For standard 90 deg. elbows L=76d÷
(
3.6
1+
For globe valves
L=114d÷ 1+
(1+
d
3.6
d
Where L-length of pipe in inches and d its diameter, also expressed in inches.
Gate valves offer practically no resistance.

530
DIAMETER IN INCHES
20
FIG. 43.
90° ELBOW
GLOBE VALVE
10 20 30 40 50 100 150 200 250
EQUIVALENT LENGTH IN FEET
LENGTH OF PIPE EQUIVALENT TO FITTINGS
Referring to Fig. 43, we find that a 15-in. globe valve
is equivalent to adding 120 ft. to the length of the pipe,
and that the resistance offered by a 15-in. standard 90-deg.
elbow is about the same as that of an 80-ft. length of pipe
of like size.
CHAPTER IX
WATER PIPING SYSTEMS
10 PLAN a system of water piping which will meet
the need of the power plant, requires a consideration,
not only of the proper sizes of the pipes but of the arrange-
ment of mains, branches, by-passes, valves, strainers, air
heads and other water conveying equipment which will
be most economical to install consistent with the relia-
bility and convenience of the system.
SUCTION LINES FOR PUMPS
Water can be raised by suction only a limited distance
depending upon the barometric pressure, the vacuum
which can be formed at the pump, the temperature of the
water, and the friction in the suction line. There will
always be a certain amount of leakage through joints, and
the valves in the pump will not hold absolutely tight, so
that it is found that the following are about the practical
lifts for different barometric pressures, with pumps and
suction line in good condition:
Barometer pressure,
in. mercury...30 29 28 27 26 25 21 22
Practical lift, ft..24 23 22.5 21.5 21 20 19
17.5
From this lift must be subtracted the loss of head in
the pipe due to friction, and the loss due to fittings and
valves, hence the suction line should be short and direct,
of full pump connection size or larger, with as few fittings
as possible and gate valves to give satisfactory operation,
and it is desirable to limit the velocity in a suction pipe to
150 ft. per minute, or about 2.5 ft. per second, or for hot
water to 75 ft. a minute.
Where a long suction line or a maximum lift is nec-
essary, install a foot valve at the inlet end of the suction
pipe, to hold the water in the pipe while the pump is idle.
For short lines and moderate lifts, omit the foot valve, as
its friction will be equivalent to a loss of 1 ft. in the
possible lift.
For suction lines laid underground, use cast-iron to
avoid corrosion, and with flange joints and gaskets, having
75
provision for supporting the line so that there will be no
sagging. For a long line, expansion must be provided for.
Connection of several suction lines to a single main
tends to uneven action of the pumps, but where this is
unavoidable a suction chamber at the inlet to each pump
is a good investment, and should be located as shown in
Fig. 44. If several pumps are on one main connected
close together, it is possible to use a single air chamber
for the entire line, and this should be arranged so that the

A
D
FIG. 44.
CONNECTION FOR SUCTION AIR CHAMBER
flow of water into and out of the air chamber, to take up
the variations in pressure, will be direct.
For handling hot water, it is necessary to have the
absolute pressure on the lift greater than the pressure at
which the water will evaporate. The lifts as given in the
preceding table are for water at 60 deg. or less. Where
water is above this temperature, the possible lift is less,
as shown in the left-hand side of the following table, the
barometric pressure being assumed as 30 in. of mercury,
and 50 ft. per minute piston speed of the pump.
SUCTION LIFT AND HEAD FOR HOT WATER
Head on
Temperature
Possible Lift
Deg. F.
Ft.
Temperature
Deg. F.
Inlet, Ft.
ΤΟ
20
160
1
80
17
170
90
15
180
00 20
3
5
100
13
190
77
120
140
8.5
4
200
9
210
11
With a temperature over 150 deg., it is practically im-
possible to raise water by suction, and the water should
come to the pump inlet under a pressure head according
76
to the right-hand side of the table, although for extreme
cases, somewhat less values of head may work satisfactorily.
For high speed pumps, the possible. lift will be somewhat
less, and the head needed for water above 160 deg. will
be greater, in order to avoid steam binding in the suction
line and pump cylinder.
If a long suction line for hot water is necessary, it will
be helpful to provide a stand pipe near the inlet to the
pump, making this of sufficient height to give a head direct
at the pump equivalent to the values as shown in the
table.
In arranging suction from a hot well, the suction inlet
should be considerably below the upper surface of the
water, to avoid drawing in oil, but above the end of the
condenser tail pipe, and preferably in a separate compart-
ment, to avoid possibility of pumping out the water seal.
If the water is badly impregnated with oil, it is well
to put an excelsior box or other filter in the pipe between
hot well and pump, making this of a size so that there will
be a cubic foot of excelsior to each 100 boiler horsepower,
and changing the excelsior each week.
An emergency connection should be made to some other
source of feed than the hot well, in order to avoid shutting
down the plant if the hot well is out of commission. When
this emergency source is the city mains, so that water
comes under pressure to the suction, an air chamber should
be used in that branch to avoid water hammer as the pump
reverses, and a foot valve should be installed at the low-
pressure intake to prevent city water backing to the hot
well.
The installation of a gage on the suction line near the
pump is useful, as any variation in this suction reading
will show faults in the suction line. If the city water
supply as well as low-pressure are used for suction, the
gage must be of the compound type, which will register
either vacuum or pressure.
In certain arrangements, it is necessary to be able to
take the suction either from a well or from an emergency
tank, particularly where a pump is used for fire service.
as well as general service, and in this case, the arrangement
of valves and piping must be carefully worked out. One
77
possible arrangement shown by Morris is as indicated by
the illustration, Fig. 45.
BOILER FEED LINES
Extra heavy material should in common practice be
employed on boiler feed pipes, and the size is ordinarily
chosen for a velocity of from 300 to 400 ft. a minute. To
secure a uniform standard, the flanges should be of the
same type as that of the main steam piping, and in order
SUCTION.
TION
TO FIRE
TO
AND SERVICE TANK

FIG. 45. CONNECTION FOR SUCTION FROM WELL OR
STORAGE TANK
to supply any boiler in case of emergency, the main line
should be laid out with either a double-header or ring
system; sufficient valves being inserted to cut out defective
sections readily.
In Fig. 46 is shown a feed-water piping diagram for
a condensing plant. With this arrangement the cold water
and condensate from the discharge pumps are turned into
a hot-well, from which the feed pumps take their supply.
The pumps are in duplicate, each being of sufficient capac-
ity to do the entire work. The injector is placed on a
branch of the cold water line and all equipment is by-
passed as indicated. Both primary and secondary heaters.
are provided, the first being placed in the main exhaust
line from the engines and the second taking the pump ex-
haust as shown.
78
COLD WATER
PUMP TO MAIN
Each branch from a boiler feed pump should be pro-
vided with a stop valve of the gate type so that the pump
may be disconnected from the main. Between this valve
and the pump there should be a check valve and a pressure
relief valve. The relief valve, which is ordinarily about
half the size of the discharge pipe, is not placed between
the pump stop valve and the feed main with the idea of

INJECTOR
FEED
PUMPS
HEATER HEATER
MAIN EXHOT
NO.I
NO 2.
I
H.P.
STEAM
8
CONDENSER
CONDENSATE
OND
HOTWELL
H.P. STEAM-
PUMP
EXHAUST
COOLING WATER
FIG. 46. FEED PIPE ARRANGEMENT FOR CONDENSING PLANT
protecting the main, but to protect the pump, as it is not
an unusual occurrence for an operator to start a pump with
the discharge valve closed.
Feed water which is to be heated by the flue gases
should be introduced at the bottom of the economizer and
discharged from the top, with flow of the water in a
direction opposite to that of the gases. If, however, the
installation is of such a nature as to make it necessary
both to receive and discharge the water at the top of the
economizer, the upper manifold should be blanked so that
the water will not take a direct path from the inlet to the
outlet.
When a feed-water heater of the steam-tube type is em-
ployed, the water should be introduced into the heater at
79
a low point and discharged at a high point with a blowoff
at the extreme top of the heater to remove floating impuri-
ties. The heater should be by-passed so that it can be cut
out and the feed water go directly to the boilers.
Whenever an economizer or closed heater is employed,
a relief valve should be placed between the inlet and outlet
water valves to protect the apparatus should heat be turned
on when the valves are closed. Relief valves used for this
purpose need not be over 3/4 in. in size.
Injectors afford a means for feeding warm water when
for any reason the heater may be out of service. Feeding
boilers with cold water may cause damage much in excess
of the cost of an injector. It is connected with the same
suction, discharge and steam lines as a pump, using a stop
valve for each of the three branches.
FEED AND SERVICE PIPING
In arranging for feed pumps, two will be required in
any case, and while one is used for boiler feeding, the other
can be employed for filling boilers, operating tube cleaners,
etc. In addition to these two lines of water service it is
necessary to have a low pressure system operating on about.
25 lb. pressure, which can be used for wetting down ashes,
for plumbing fixtures, washing floors, for the makeup
water, and other similar services. Supplementing this
house service, there should be a fire service system, the
pump for which should be able to maintain 100 lb. pressure
running at full speed. These four services must be avail-
able at all times, although it is not necessary or desirable
to keep the fire service pressure on all the time.
Various combinations of pumping conditions, with dif-
ferent arrangements of economizers, heater and meters
necessitate a careful study before a reliable and flexible
piping system for the pumps can be decided upon. Figure
47 shows a detailed arrangement which applies well to
some systems with an economizer installation. This plan
provides for the following requirements:
1. Any part of the feed system may be shut off with-
out reducing the capacity more than one-fourth, for four
units.
2. Hot-well water may be fed to the economizers
when the heater is off.
80
3. The boilers with economizers off may take their
feed from other economizers which are in operation.
4. An abundance of feed reserve is provided.
WATER PIPING FOR SPECIAL SERVICE
Water for convenience of occupants in various parts
of low buildings is furnished at comparatively low pres-
sure, usually about 20 lb. It is customary to supply this

LOW PRESSURE
HOUSE SERVICE -
AUX FEED MAIN-
ECONOM-
-IZERS
BOILERS
TO INTAKE
TO HOT WELL
FIRC
FEED PUMA
FLED PUMP
PUMP Nº1:
N°2
N°3
HEATER PUMP
-METER
FIRE MAIN
REGULAR FEED MAIN
HEATER
CITY WATER
FIG. 47. FEED PIPE SYSTEM FOR ECONOMIZER INSTALLATION
from an elevated tank or city mains rather than direct
from a pump.
For factories the estimated amount of
water used a day is 100 gal. per capita. In high office
buildings where the supply tank is located on the roof it.
is necessary to use pressure reducing valves for the lower
floors to prevent an excessively high pressure on the
plumbing fixtures. In such cases the pressure on the
different floors varies from 10 to 100 lb.
COLD WATER FOR GENERAL SERVICE
Cold water service piping is extremely simple, consist-
ing of a single main with branches to fixtures. The water
is delivered to the roof tank up through the main and fed
down as needed to the fixtures, except where pressure re-
ducing valves are required, when separate supply and
$1
service mains are necessary below the location of the re-
ducing valve.
In place of the elevated tank feeding by gravity, some
plants have air pressure tanks in the basement which force
the water to the different floors. By this provision a high-
pressure tank may serve the top floors and a low-pressure
tank the lower part of the building. One pump may be
used for this arrangement, a pressure reducing valve feed-
ing into the low-pressure system. The low-pressure air
tank prevents abnormal pressure on the low-pressure fix-
tures due to a leaky pressure reducing valve.
HOT WATER SUPPLY SYSTEM
Supplying hot water is usually a difficult detail to ar-
range as it will cool during transmission and while lying
still in the fixture connection. With single piping great
quantities of cool water are allowed to run to waste before
hot water is secured, unless the faucets are close to the
heater.
In the power plant lavatory, hot water may be taken
direct from the boiler feed main at boiler pressure, but this
presents objectionable features in that it robs the boiler
of water and necessitates high pressure plumbing fixtures.
Reducing valves might be used, but a slight leak will
cause the pressure to be practically equalized with resultant
difficulty at the faucets unless high pressure fixtures are
used.
Live steam is commonly used for heating house water,
the arrangement of the coil depending upon the amount
of hot water required; in all cases, however, the steam
supply to the heater should be under thermostatic control
so that the water will not reach the boiling point when
the demand for hot water is light.
Exhaust steam is convenient for heating house water,
as the temperature will never exceed the boiling point and
the heater can be proportioned to give the necessary supply
at the desired temperature. The type of heater to employ
depends upon the service demanded. Where large quan-
tities of hot water are required almost continuously the
tank type containing a properly proportioned steam coil
is most suitable. This may be either vertical or horizontal,
82
STEAM
SUCTION TEE
D
DRAIN
A
COLD WATER
HOT WATER
DRIP
HEA TER
DRIP
CHECK VALVE
COLD RE TURNS
STEAM
PIPE
HEATING
DRAIN
COLD RETURNS
C
COLO
SUPPLY
as shown in Fig. 48, A and B. Where a large quantity is
used only at intervals, the arrangement shown at C has
advantages. In this, comparatively small heating surface
is employed apart from the main body of water, which is
heated by circulation through the heating pipe and storage
tank. By proper proportioning to the demand this ar-
TO SERVICE
STEAM
B
RELIEF
THERMOSTATIC
VALVE
RELIEF VALVE
THERMOSTATIC

VALVE.
TO SERVICE
HERTER
CHECK VALVEÏ
-THERMOSTATIC
VALVE
RELIEF
VALVE
HOT
WATER SERVICE
HOT WATER STORA CE
FIG. 48. CONNECTIONS TO SEVERAL TYPES OF HEATERS
rangement gives good results and provides an independent
heating element that is easily cleaned or repaired. Where
steam is always available an instantaneous heater, made by
connecting a suction tee to the steam and cold water piping,
as shown in Fig. 48, has the advantage of being inexpen-
sive and is frequently employed in washrooms of power
plants and factories.
Tank pipe heaters are usually made with sufficient stor-
age capacity, but if occasion demands, storage tanks may
he connected up in a manner similar to that shown in
SUPPLY
TANK
STEAM
DRIP
83
Fig. 48. All hot water pipes, heaters and storage tanks
should be thoroughly insulated to prevent waste of heat.
To secure hot water at the faucets without excessive
waste requires careful planning of the piping system. By
means of a return pipe, the water in the main may be
maintained hot, but the lines from the mains to the faucets,
unless kept running, will get cool, and for this reason
should be as short and direct as possible.
When the return loop system of hot water circulation
is employed, hot water may be drawn from any part of
the main or return. Where the hot water mains are mostly
horizontal it may be found necessary to force the circula-
tion, the means employed being usually a centrifugal
pump.
COLD DRINKING WATER
Fresh cold water to drinking fountains is one of the
luxuries in many office buildings. This is supplied from
a circulating system very much as is hot water, the dif-
ference being that a water cooler is used instead of a
heater. The fixture is always close to the supply pipe to
prevent waste of cold water, and the circulation must be
forced unless the cooler is located at the top of the sys-
tem, which is not usually advisable.
FIRE SERVICE
When separate pumps are not used exclusively for fire
service, it is essential that separate discharge lines, each
provided with the necessary shutoff valves at the pump, be
installed. In case of fire, therefore, these valves being
grouped, may be operated in the shortest possible time,
and, as a further aid, an established system of tags or
painting may be followed as, yellow valves closed; and red
valves open.
To insure a continuous supply of water to the pumps,
a suction connection may be provided with the local city
water supply discharging into an open well or other point
convenient to the regular pump suction.
As an aid to keep the system in operation the longest
possible time during a fire, a steam-supply and water lines.
should not be suspended from overhead, but should be so
supported and protected as to remain intact even if the
roof and floors above fall on them.
84
HYDRANTS AND HOSE LINES
Fire mains supplying hydrants and standpipes are gen-
erally laid out to conform to local requirements and con-
ditions, although wherever possible some form of loop
should be employed, thus permitting any section to be
shut off and still maintain sufficient fire protection. To
avoid possible freezing and to facilitate proper hydrant
connections, main should be buried to a depth of no less
than 5 to 6 ft., and where supplying important buildings,
should be at least 6 in. in diameter.
Hydrants, which should be provided with two or more
212-in. outlets and with an inlet equivalent in size to the
main, should be placed at a distance from the building
equal to its height and with hose connections facing the
building. They should be located at such intervals that
not more than 300 ft. of hose need be laid in any one line,
and so that about 10 first-class fire streams can be con-
centrated on any large building.
Standpipes carried on the outside of buildings should
be provided with one or two hose connections with valves
at each floor and possibly two such connections at the roof;
a valve and drain at the lower end of the standpipe is
desirable to clear the line of water after use and prevent
freezing. No pipe smaller than 4 in. in diameter should
be used for this service, and when two connections are
taken off at each floor a 6-in. standpipe is advisable.
Roof tanks used in connection with sprinkler systems
should be so placed as to furnish a minimum head of 25
ft. and of such size as to provide a continuous supply of
water to all the sprinklers in any fire section for a period
of 20 min., assuming each such sprinkler head to require
20 gal. per minute. Standard tank sizes range from 10,000
to 50,000 gal. capacity.
Three common methods of supplying roof tanks with
water are by the use of a float and lever connected to the
steam pipe of the pump; the use of a float and lever ar-
ranged to operate the water valves in the line discharging
into the tank; and by means of a float, pulley and telltale
placed on the wall, enabling the operator to observe and
control the feeding arrangement by hand.
85
SPRINKLER SYSTEMS
In laying out sprinkler systems, the most effective dis-
tribution of water may be obtained by providing central
feed lines and short branches wherever possible, reduction
and elimination of friction losses, provision for proper
drainage, use of long turn fittings and bends and the pre-
vention of sagging of the lines due to insufficient or im-
properly spaced hangers.
TABLE XIII. SPACINGS OF AUTOMATIC SPRINKLER FOR
PRESSURES GREATER THAN 20 LB. PER SQ. IN.

Spacing of sprinklers, ft.
Standard mill
Open-joisted ceilings
construction
Kind of
hazard
Width of bay, ft.
Sprinklers
Sprinkler8
at right
parallel
12
11
10 9 8 and
under
angles to
with
joists
Joists
Medium 8 9 10 11
Special 7 8 9 10
12.
8
10
11
7-1/3
9
*The terms "Medium hazard" and "Special hazard" relate
to the contents or occupancy of each room. Specially
hazardous places are such as picker rooms, planing or
sawing departments of wood-working establishments, paint-
ing or varnishing rooms, etc.
For prossures less than 20 lb. per square inch use
spacings 1 ft. less than the above.
In determining the size of feed mains and risers, each
floor or fire section of a building is considered as one unit.
Any number of floors or fire sections may be placed on the
same riser and that having the largest number of sprink-
lers determines the required size of feed main or riser.
Where, however, the number of sprinklers on any floor
or fire section exceeds 200, additional risers should be
provided and unless absolutely necessary no more than
eight sprinklers should be placed on any branch line. At
least one sprinkler should be allowed for every 100 sq. ft.
of floor area, the sprinklers never to be more than 12 ft.
apart in either direction and preferably not more than 10
or 11 ft.
Dry-pipe systems should be so arranged, if possible,
that all pipe lines drain back to one main drip valve
located at or near the dry-pipe valve.
86
Placing the dry-pipe valve as near the main riser ast
possible is desirable, and under no conditions should this
valve control more than 300 sprinklers. Where exposed to
cold, the valve should be located in an approved under-
ground pit or enclosed in a room or closet of sufficient size
to give preferably 30 in. free space on all sides of and
above and below the valve.
All distributing piping should pitch back to the riser
not less than 1/4 in. in 10 ft. with the riser as near the
distributing center as possible.
The number of sprinklers capable of being cared for
by various sized pipe is indicated below:
Size of
Pipe, In.
3/4
PIPE SIZES FOR SPRINKLER SYSTEM
No. of
Sprinklers
1
Size of
No. of
Pipe, In.
Sprinklers
TQ2 ∞ LO
2
36
31/2
55
3
4
80
5
5
140
6
200
1
114
11/2
2
21/2
10
20
Whenever a pipe under air pressure, as used in the dry-
pipe system, is placed underground it should be of wrought
iron painted on the outside with two coats of good rust-
proof paint as asphaltum or tar, one coat before pipe is laid
and the final coat after being placed in position with joints
screwed tight.
All valves must be of Underwriters Approved Pattern,
and when 2½ in. and over in size must have flanged ends,
while those 2 in. and under may have screwed ends.
CHAPTER X
STEAM PIPING, MAINS AND HEADERS
HERE leads connecting boilers and steam headers
WHERE leads
are made up of vertical and horizontal runs, long-
turn bends should be used instead of ells, and when of
considerable length, the scheme illustrated at C, Fig. 49,

BOILER
AUTOMATIC STOP VALVE
HEADER
BOILER
A
B
HEADER
FROM BOILER
C
TO SEWER
BOILER
FIG. 49. TYPICAL BOILER BRANCH CONNECTIONS AND
PROPER LOCATION OF VALVES
is preferable in order to avoid vibration and to keep the
weight of the pipe along a line drawn through its sup-
ports. For high-pressure saturated steam, steel piping and
cast-iron fittings are used; if superheat is employed, only
cast-steel valves and fittings will withstand the high tem-
peratures encountered. For pressures up to 125 lb. per
square in., standard fittings are applicable; above 125 lb.
extra heavy fittings must be employed.
88
All boilers must be provided with a stop valve of the
gate or globe type, and except in single-unit installations.
the use of some form of automatic non-return valve placed
between the main valve and the boiler is recommended.
This should be located at the highest point of the lead and
as near the header as possible.
Placing the two valves as shown at D, Fig. 49, the
automatic valve can be taken apart while the header is in
operation.
To avoid the collection of water around the stuffing
box, steam valves should not be placed with stems down-
ward, and where impossible to place the valves so as to
be accessible from the top of the boiler, the floor or a gal-
lery, bevel gearing and rod, or an endless chain may be
employed. In many large plants these valves are remotely
controlled by means of electric motors, air, steam or water
pressure.
When specifying valves for superheated steam, care
should be taken that no soft composition is used. In a
globe valve the disc, seat and that part of the stuffing-box
gland coming in contact with steam should be made of
gun metal, nickel steel or other hard alloy. The same may
be said in regard to gate, seat and gland of a gate valve.
Nonreturn valves as used on boiler leads are primarily
check valves fitted with a stem and hand wheel, allowing
them to be operated the same as an ordinary globe or gate
valve, and so constructed that with a reversal of steam
flow the disc will seat and shut off further flow of steam.
Cushioning is provided by means of a piston working in
a dashpot or a spring located either externally or internally.
An added feature of some of these valves is the ar-
rangement employed by means of which they may be
closed when a reduction of pressure occurs beyond the main
stop valve, as in the case of a header failure. The reduc-
tion in header pressure acting on a pilot valve causes this
to open and admit steam taken from the boiler to the top
of a piston above the disc of the automatic valve. This,
having an area greater than that of the disc, forces the
disc down on its seat, thereby shutting off the flow of steam.
When normal header pressure is again established, the
pressure above this piston is released and the valve allowed
to open.
89
BOILERS
FIRING AISLE
ARRANGEMENT OF STEAM HEADERS
Engines or turbines may be connected to the boilers
feeding them by means of the single header, the loop or
ring header, or the unit system, the method employed de-
pending largely upon local conditions and requirements.


TURBINE
NO.1
NO.2
NO.3
UR
TURBINE
NO.4
NO.5
TURBINE
NO.6
NO.7
No8
TURBINE
NOJ
NO.2
BOILERS
FIRING AISLE
No. 3
TURBINE
NO.4
TURBINE
NO.5
NOG
CROSS
CROSS.
NO.7
COMP
ENGINE
NO.8
COMP
ENGINE
SINGLE HEADER ARRANGEMENT
BOILERS
FIRING AISLE
SINGLE LOOP ARRANGEMENT

NO.I
NO.2
TURBINE
NO.3
NO.4
EXPANSION
JOINT
NO5
NO.G
TURBINE
NO.7
NO.8
Nag
NO-10
EXPANSION
JOINT
TURBINE
UNIT ARRANGEMENT
FIG. 50. SINGLE HEADER, SINGLE LOOP AND UNIT
ARRANGEMENT OF STEAM MAINS
Due to its simplicity, low first cost and provision for
expansion, the single header is well adapted to small plants,
although if any section of such a header must be cut out, it
will interfere to some extent with the operation of the
plant.
90
The loop header finds its widest application in installa-
tions where a large number of engines and pumps are
crowded together in a comparatively small space.
Sec-
tionalizing valves in the main and cross-connections allow
any section to be isolated for repairs.
In large power stations, the tendency is to employ the
unit system, in which each prime mover is supplied by its
individual group of boilers; the various units are tied to-
gether, however, by equalizer pipes so that there is in
reality a header of diminished capacity between them.
Present-day designers regard the function of the header
as that of an equalizer rather than a storage reservoir, and
make the header the same size as that of the largest con-
necting branch pipe. In such an arrangement, receiver-
type separators having a volume of from two to four times
that of the high-pressure cylinder are installed as near the
throttle valve as possible. The use of such separators
provides a full supply of steam close to the throttle, makes
possible much smaller header and branch connections
(thereby greatly reducing the cost of the piping system
throughout) insures drier steam to the engine and reduces
radiation losses.
Like the boiler leads, headers carrying high-pressure
saturated steam should be made up of steel piping with
cast-iron fittings; for superheat, use only cast-steel valves.
and fittings.
If, in the installation of steam headers, the formation
of pockets cannot be avoided, provision should be made for
drainage by means of traps which should at all times be
maintained in proper working order.
AUXILIARY STEAM LINES
In laying out power plant machinery, there are always
a number of auxiliaries that take steam at boiler pressure,
but their locations are secondary to the main units; the
piping to these is, therefore, more or less complicated, mak-
ing necessary the use of crossovers, off-sets, bypasses, re-
ducing fittings, etc., in order to accomplish the desired
result. It is usually found advisable to install an auxiliary
main connected to the boiler header at convenient points.
The advantages of this are that the main header is not cut
up by numerous outlets to auxiliaries which in many cases
91
would not only be more expensive than the additional
header, but interfere seriously with the flow of steam to
the main units, reducing the efficiency of transmission.
The auxiliary header also gives more liberty to the de-
signer in locating small machinery. The same general
principles govern the arrangement of the auxiliary piping
as the main piping, the only difference being in regard to
details of leads to various types of apparatus.
AUXILIARY MAINS AND CROSS CONNECTIONS
Auxiliary mains should be installed at sufficient dis-
tance from the steam header to allow for expansion and
contraction in the case of one being cold and the other hot,
and should be pitched in the same direction as the flow of
steam with provision for drainage.
Preferably, steam should be taken out of the top of the
main, and by keeping the main well drained, any auxiliary
apparatus may be started immediately and not be liable to
delay due to the auxiliary cylinder filling with condensa-
tion.
Cross connections which of necessity are generally of
comparatively short length, must be provided with means
to compensate for the effects of expansion and contraction;
and for flexibility of operation, it is desirable that they
contain some form of cutoff valve in addition to a valve on
each side of the tee where they join the mains.
Stop valves placed next to the main should be used on
all auxiliary branches in addition to the throttle valve,
which should always be a globe or an angle valve and
should be so arranged as to be accessible for repairs after
closing the stop valve.
REDUCED PRESSURES
When steam, air, illuminating gas, etc., are utilized at
pressures lower than that at which generated, some form
of automatically-operated throttle valve generally known
as a pressure reducing or, or sometimes termed, pressure
regulating valve, is employed.
Figure 51 gives the size of supply line and reducing
valve needed for a reduction from pressure of 75 to 250 lb.
to any lower pressure. If a service pressure is to be carried
at 35 lb. in a 8-in. pipe with initial pressure at 150 lb., the
92
HIGH PRESSURE, LBS PER SQ. IN.
125
150
200
250
size of supply line will be found as indicated by the
arrowed line at 4.5 in. The reducing valve will be placed.
on the 4.5-in. line to save expense, and will feed into a 6-in.
branch or outlet.
DRAINING APPARATUS
Water may gain admission to steam pipes from the
condensation of steam that takes place in the pipes, on ac-
count of insufficient or improper insulation, or from ad-
mitting steam to cold pipes.
DIAMETER SUPPLY LINES,INS.

2 3 4
5 6 7 8 9
10
13
| 1 2 3 4 5 6 7 8 9 10 11 12 13 MIS
DIA SERVICE LINES IN.
0 10 20
FIG. 51.
30 40 50 60 70 80 90 100
100 110 120 130 140
SERVICE PRESSURE LBS. PER SQ. IN
SIZES OF REDUCING VALVES AND SUPPLY LINES TO
BE USED WITH VARIOUS SERVICE PRESSURES AND SIZES OF
SERVICE LINES
In high-pressure piping, water is dangerous. If car-
ried into the engine cylinders in considerable quantities, it
is liable to wreck the engine, or at least rupture the cylin-
der heads. Condensation in the mains is likely to produce
water hammer, which in turn causes vibration, tending to
loosen the joints.
Piping should be erected, if possible, so as to avoid
pockets where water may collect; but wherever such
pockets cannot be avoided, and at points where risers are
connected, drain pipes of ample capacity should be pro-
vided. Where small branch pipes are connected with
steam mains by reducing tees, in such a way that the
steam flows from the main into the branch pipes, and also
93
when taper reducers are employed, drips should be con-
nected at the lowest points, as shown in Fig. 52.
To drain the condensation from a horizontal run of
pipe, the simple form of drip receiver shown in Fig. 53
may be employed. This consists of a short length of pipe

DRIP
TAPER REDUCER
DRIP
DRIP
REDUCING TEE

REDUCING COMPANION
FLANGES
FIG. 52. LOCATION OF DRIPS AT REDUCING FITTINGS
with a blind flange at the lower end through which the
drip pipe is connected. A gage glass is provided to indi-
cate the amount of water present.
SEPARATORS TO REMOVE WATER
Separators or "water catchers" are widely employed to
prevent water from gaining entrance to turbines and to
cylinders of reciprocating engines, where its presence is
likely to cause damage. In order to secure the best results,
the separator should be located as near the engine cylin-
ders as possible, because if there is any considerable length
of pipe beyond it, there will be opportunity for further
condensation and the steam will again become moist. It
is also desirable to have the separator of large size, or of
the receiver type, because in this way a steam-storage reser-
94
voir is provided which insures greater uniformity of pres-
sure in the engine cylinder up to the point of cutoff, and
overcomes in large measure the vibration in the steam

SHORT LENGTH
GAGE GLASS
OF PIPE
DRIP
FIG. 53.
SIMPLE FORM OF DRIP RECEIVER
piping due to the interruptions of the flow of steam from
the regular and frequent opening and closing of the engine
valves. Receiver separators commonly have a volume
three or four times that of the high pressure cylinder.

Drip each End
d Header
SEPARATOR
Drip
Throttle
ENGINE
BOILER
FIG. 51.
DRIP ARRANGEMENT FOR ENGINE PIPING
When drips coming from different sections of piping
which are likely to be shut off are connected to the same
trap, both check and gate valves should be placed in the
connections.
95
In Fig. 54 is shown a typical arrangement of piping
between the boiler and the engine in which a drip should
be placed at each separator and also at each end of the
main header. Where the separator must be placed some
distance from the engine, a common arrangement of
throttle and cylinder drips is shown in Fig. 55.
In the case of separators, the size of drip pipes is
usually fixed by the outlet as determined by the manufac-

THROTTLE
DRIP
STEAM
PIPE
ENGINE
CYLINDER
FIG. 55.
EXHAUST
DIPE
ENGINE THROTTLE AND CYLINDER DRIPS
turer. For main headers, the drip pipes are from 34 to
1 in., while throttle and cylinder drips are commonly
given a uniform diameter of 1½ in. Drip piping is not
expected to care for any sudden rush of water.
Ordinarily, condensation from high-pressure drips is
trapped to a receiving tank, thence pumped to the boilers.
Where the drips are widely separated, individual traps
should be provided, as there is likely to be sufficient differ-
ence in pressure to cause a backing of water from one pipe
into another. When two or more drip pipes are taken
from points near together, and where the pressure differ-
ence is likely to be slight, they may be connected with the
same trap. It is usually best to seal them by means of a
check which carries a water column above it.

96
Outlet traps can discharge their contents only against
a lower pressure. Where condensation is required to be
discharged at boiler pressure, a device known as a return
trap is used.
DI
A
B
FIG. 56. RETURN TRAP PIPING CONNECTIONS
Shown in Fig. 56 is the piping arrangement for a typi-
cal return trap. Condensation collects in the receiver, R,
under pressure, and is lifted into the return trap through
pipe A by the pressure. The trap is placed 3 ft. or more
above the boiler water level. When filled, the receiving
bowl tilts and opens the steam valve, admitting steam un-
der boiler pressure through pipe C, which should connect
97
directly to the boiler. Pressure on the trap and boiler are
thus equalized, and water will pass by gravity from the
trap to the boiler through pipe B.
Horizontal check valves are placed in pipes A and B at
the trap connection. An extra check valve and a stop
valve are inserted below the water line in the outlet pipe,
B. Vent pipe D can be left wide open in cases where the

145 28.
A
H
-147LB.,
FIG. 57. HOLLY GRAVITY RETURN SYSTEM
water supply is under low pressure or nearly cold; if un-
der high pressure and the water has a high temperature,
the vent can be partly closed.
HOLLY GRAVITY RETURN SYSTEM
Drip systems are in practical operation which return
the water of condensation directly to the boiler. These
systems, however, require special provisions; for instance,
the Holly gravity return system, shown in Fig. 57, which
operates as follows: Drip pipes from various points are
98
led to a receiver, which is placed at a point below the lowest
drainage outlet, usually about the central point of the
plant. A riser pipe from the receiver reaches to the dis-
charge chamber, which is 30 ft. or more above the boiler
water level, and a return pipe connects the discharge
chamber to the boiler at some point below the water level.
Water of condensation is carried by entrainment with the

SIPHON
LOOP
HP
JACKETS
RECEIVER
APŚ
TRAPS
HPSTEAM
-TO HOT WELL
L.P
FIG. 58.
DRAIN FOR CYLINDER AND RECEIVER
steam to the discharge chamber, which is at an altitude to
give head to make the return to the boiler.
This system is kept free from air, and the riser action
is accelerated by the venting of a small amount of vapor
from the discharge chamber, commonly into the feed-
water heater.
DRAINING RECEIVERS
Draining the jacket and receiver of a compound engine
may be accomplished with the system shown in Fig. 58.
Steam and condensation from the jacket of the high-pres-
sure cylinder passes into the coil of the receiver, from
which it goes to the jacket of the low-pressure cylinder.
The condensate is trapped into the shell of the receiver;
also that from the heating coil. The receiver itself is
drained through a trap to the hot well.
99
EXHAUST STEAM LINES
Atmospheric exhaust lines should be of the same size
as the exhaust main, or if supplied by more than one such
main, equal to their combined areas, and if used in con-
nection with noncondensing units should be provided with
a sealed drain and fitted with an exhaust head with drain
and a short seal. Where engines and turbines are operated
condensing, no exhaust head is necessary.
To care for expansion and contraction and prevent leak-
age, exhaust and drain pipes passing through roofs should
be fitted with some form of sleeve and umbrella and where
the vertical run is more than 25 ft., the depth of the drop
flange of this umbrella should correspond to the amount of
travel caused by expansion. This for an exhaust line sub-
ject to temperature variations of from 32 to 212 deg. F.
would be about 1/4 in. for every 100 ft.
Exhaust heads are generally made of sheet metal or
cast iron so constructed internally as to cause a change of
direction in the flow of the steam, while the entrained
water which tends to follow a straight path continues and
is caught in some suitable form of receptacle or trough.
Because of the oil which this water generally contains, it is
trapped directly to the sewer.
BACK-PRESSURE VALVES
Back-pressure and atmospheric-relief valves, which
serve primarily as safety valves on exhaust-steam-heating
and engine-and-turbine atmospheric-exhaust lines, are of
three general types; single, double or balanced, and multi-
ple for horizontal or vertical mounting. The single-seated
valve is best for diameters up to 6 in.; for larger sizes bal-
anced and multiple valves are more suitable. When used
in connection with condensing engines and turbines, these
valves are frequently water sealed, a 1/2-in. connection sup-
plying all the necessary water for such service.
Atmospheric exhaust lines used in connection with en-
gines and turbines should always be installed vertical and
the relief valve used in connection therewith may be 1 or 2
in. less in diameter than this line, a 14-in. valve being
suitable for a 16-in. line, a 12-in. valve for a 14-in. line,
etc.
CHAPTER XI
PIPING CONNECTIONS TO POWER PLANT
E
EQUIPMENT
ACH steam-using or water-handling machine in the
power plant has individual characteristics which gov-
ern to some extent, its piping connections to the steam
and water mains and to the drip system. To obtain the
most satisfactory service from the equipment, the piping
must be so arranged that it will always meet the needs of
the service. Steam for power purposes is usually required
to be dry and in many cases super-heated, free from scale.
and other foreign solids; reciprocating units require cylin-
der oil sprayed into the inlet; steam for heating may be
wet, clean or oily depending upon its use; separators, re-
ceivers, bypasses, reducing valves, air heads, all come in
for their service in piping up power plant equipment.
PIPE CONNECTIONS TO STEAM PUMPS
Direct-acting steam pumps take steam nearly full
stroke, so that there is no necessity to provide receiver
space in the branch, and if taken from the top of the main,
which is properly drained, no drip connections to the
branch will be necessary. When the pump is located nearly
under the main, the branch will need no additional support,
but should have a stop valve at the main and a throttle
valve at the pump. The stop valve is convenient when nec-
essary to repair the throttle valve, which is subject to con-
siderable wear, due to being kept partially open a great
part of the time. A scheme resorted to occasionally to pre-
vent excessive wear of the throttle valve is to provide a by-
pass with a valve one-fourth the size of the throttle. This
valve is used to regulate the pump and naturally takes the
wear, but being smaller than the throttle will be opened.
wider, hence cutting of the seat will not be so great and
when worn it is replaced at less expense.
In steam leads to pumps provided with governors, the
governor should have a bypass pipe and valve and in the
governor branch there should be a valve on each side of the
101
governor to insure continuous running of the pump in case
the governor needs repairs.
Exhaust from steam pumps is generally used for heat-
ing purposes and when it is delivered to a main serving a
number of pumps or other equipment each individual ex-
haust connection should be provided with a valve so that
any pump may be removed or repaired without interfer-
ence with other equipment.

13
STEAM EJECTOR
INCREASE
ELBOW
FLAP
STRAINER
100000
FIG. 59.
•
STEAM EJECTOR USED FOR PRIMING PUMP
Each suction and discharge water connection should be
provided with a valve close to the pump. The use of air
heads in suction piping has been discussed in Chapter IX;
they may also be used to advantage on the discharge con-
nection of some reciprocating pumps to give steadier flow
and prevent hammering, if the pump itself is not provided.
with an air chamber for this purpose.
In starting up a pump which has been idle for some
time, there will almost always be air in the suction line,
and pumping out may become a tedious process. To avoid
this, provision should be made to discharge the air from
between the valve decks by a short pipe and valve located
at about 1/4 in. below the discharge valve deck; where there
is a long lift, and for centrifugal pumps, provision should
be made for priming the pump with water before starting,
and a foot valve should be used on the inlet pipe. If water
cannot be supplied for priming, the air may be exhausted
from the pump by a steam ejector connected as shown in
Fig. 59.
102
In addition to a hand operated valve in the discharge of
a centrifugal pump, there should also be a check valve to
prevent back flow of water in case the driving power fails.
INJECTOR PIPING AND VALVE ARRANGEMENT
Connections for an injector are shown in Fig. 60.
Steam pipe D should always be the same size as the injec-
tor connections, and must be connected to the boiler at the
OVER HEAD
TANK
K
STEAM,

DISCHARGE
F
WATER SUPPLY
J
B
OVERFLOW
THREADED FOR
WASTE PIPE
FIG. 60. PIPING CONNECTIONS FOR INJECTOR
highest possible point, and independently of other pipe in
order to insure best results. This pipe should be blown out
with steam before connecting the injector.
The water supply pipe should be as large as the injec-
tor connections, and where the lift is over 10 ft., it should
be one or two sizes larger, reducing to injector size as near
the injector as possible. In this line the valve H should be
a globe valve. On a long lift a foot valve should be placed
on the lower end of the suction pipe. Without a foot valve,
every time the injector is started, all air must be exhausted
from the suction pipe before water can reach the injector,
·
103
and considerable steam is wasted. With a foot valve, the
water is held in the pipe when the injector is stopped.
When water is delivered from an overhead tank or
from city water mains, it frequently happens that a heavy
pressure exists, and in this instance, to facilitate starting
on low steam, some prefer to use two globe valves, H and
M, in the water supply line. The valve H, placed as near
the injector as possible, regulates the water supply, while
valve M, placed several feet away is employed to reduce the
the pressure. In the discharge line there should be a check
valve and a stop valve, as shown by F and G.
To start the injector, the valve D in the steam line is
opened full, and then open the valve H in the water supply
line, with which the amount of water delivered to the
boiler can be regulated. When this valve has once been
regulated properly, only the steam valve will be used to
start and stop the injector, unless the steam pressure car-
ried has altered to a great extent.
FEED-WATER HEATER PIPING
Heating of boiler feed-water is usually done with ex-
haust steam by means of either open or closed feed-water
heaters. The principal precautions to be taken in making
the exhaust steam connection are to make certain that there
is always an opportunity for steam to escape to atmosphere
in case the pressure reaches the maximum allowable, and
to provide some means for removing all oil from the steam
so that it will not contaminate the water, in the case of an
open heater or coat the tubes when a closed heater is used.
Steam may be passed through the heater, which re-
quires both an inlet and outlet connection, or just what
steam the heater will condense may be drawn from the ex-
haust main by induction. In the former case, the heater
is usually in a bypass of the main exhaust and requires a
gate valve in each connection and a valve in the main be-
tween the connections. The induction type heater requires
but one connection and one cut-out valve, a vent being pro-
vided to prevent air binding, with gate and check valves as
shown in Fig. 61. In either case, however, it is essential
to provide a back pressure valve if the temperature of the
water is to be greater than 210 deg. F., and the inlet con-
104
nection must be provided with an oil separator which may
be a part of the heater itself.
Water comes to the open heater under pressure, its
flow being controlled by a float operated valve but a globe
valve is also necessary to shut off the supply manually.
Where heating returns and clean drip-water are available

Vent
AIR SEPARATING TANK
Discharge from
Vacuum Pump
A
Note:-
The Area of Pipe B
to be twice that of
Fipe A
-Not less than 6-0-
To Drain
Make up
Water Supply
To Atmosphere
To Drain
Note:-
With Reciprocating Type Boiler Feed Pumps
allow at least 24 inches (as much more as
practicable) from C.L. of Suction Outlet to
Pump Valves. With Centrifugal Pumps
Consult Pump Manufacturer.
To Boiler Feed Pump
FIG. 61.
To Heating System
Multiply Maximum Back Pressure
carried in Heater by 3 to determine
least Dimension in Feet
Water Inlet Valve
Suction Outlet
See Note
-Returns Inlet
Cut-out
Gate Valve
Exhaust to
Atmosphere
Back Pressure
Valve
Exhaust from
Engine
Returns from High
Pressure Traps
Overflow
GREASE TRAP
FEED
WATER HEATER
Drain
H
To Sewer
PIPING CONNECTIONS FOR INDUCTION TYPE OF
OPEN FEED-WATER HEATER
they are fed to the heater by a separate inlet from an air
separating tank as indicated. The suction outlet is usually
near the bottom and is provided with a shutoff valve. An
overflow pipe to the sewer must be provided which should
have a float controlled valve in case the heater is under
pressure; a drain pipe to clean the heater and a drip to
waste from the oil separator are also essential.
Steam piping of a closed heater is essentially the same
as that for the open type, the water inlet, however, is at
the bottom and the outlet at the top with only shutoff
105
valves in the connections. A blowoff connection should be
made from the lowest point in the water space, the precipi-
tation being in the form of mud and not likely to injure
the valve.
BOILER FEED LINE CONNECTIONS
Branch pipes to boilers are generally supplied by the
boiler manufacturer. Check and gate valves should be
placed in each branch line to a boiler, so that the water
cannot return from the boiler to the feed line should the
boiler pressure rise above that in the feed main.

FEED MAIN
2
9999
A
B
A
A
B
AAA
FEED MAIN
FIG. 62. TYPICAL ARRANGEMENT FOR BRANCH FEED LINES
Various methods of placing the valves in the branch
lines to the individual boilers of a battery are illustrated
in Fig. 62, in which A is a stop valve, B a check valve and
C a regulating valve.
Beginning at the left, No. 1 shows the most approved
arrangement where the boilers are operated continuously
and the regulating valve is subjected to hard usage. With
this arrangement, the stop valves are left wide open, ex-
cept in case of repairs to the check or regulating valve, and
are, therefore, free from wear. In arrangements Nos. 2
and 3, which are employed in common practice, one stop
valve has been omitted and the regulating valve is made to
serve as a stop valve in case of repairs to the check valve.
In heating work, the stop and the regulating valves are
usually combined as in No. 4, making it necessary to shut
off the pressure in the feed main in case of repairs to the
check valve. This arrangement should not be adopted in
power work or in large and important heating plants.
106
Wherever possible, all frequently used valves in the feed
line should be accessible from the boiler-room floor, or from
a platform at the engine-room level, or extension stems
may be used as shown in the connection to boiler No. 2,
Fig. 62.
Where automatic regulators are installed, many en-
gineers advocate the provision of a bypass with a hand

FIG. 63.
FEED WATER DISCHARGE TUBE IN
WATER-TUBE BOILER
regulated valve permitting repair of the regulator without
interruption of feed water flow.
FEED LINE DISCHARGE
Feed water should enter the boiler at a point con-
siderably below the water line in order to prevent steam
from entering any portion of the feed branch and causing
water hammer when the feed valve is again opened. In
order to minimize the expansion and contraction strains,
it is advisable not to allow the feed water to come in con-
tact with the boiler until it has been heated to the tempera-
ture of the water in the boiler.
For return tubular boilers, the following method of
feeding is recommended: The feed pipe enters the boiler
through the front head just above the top row of tubes,
and about 3 in. from the shell and extends to within a foot
of the back head, at which point it crosses over to the other
side of the boiler. It then passes down between the tubes
107
and the boiler shell and discharges below the lowest row of
tubes toward the axis of the boiler. If the water carries
much lime or magnesia, however, it is best to shorten this
internal arrangement.
An arrangement for feeding a water-tube boiler is
shown in Fig. 63, in which the internal feed-water tube dis-
charges into the coldest part of the boiler. The nozzle at-
tached to the drum has a blind flange which closes the end
opening, and the feed branch opening is at the side of
the nozzle. As the feed-water tube is the same size as the
boiler tubes, it may be cleared of scale at the same time.
WATER COLUMN CONNECTIONS
Extra heavy tees and crosses, with open ends plugged,
should be used in the steam connection of a water column
so that the pipe may be inspected. The column should be
so placed that the bottom of the water glass is no less than
3 in. above the top row of tubes.
For high-pressure work, a flanged connection is the
most satisfactory method of attaching a column. By sup-
porting each column free from the pipe work, the piping
is more secure, and the pipes may be disconnected without
disturbing the columns or their connections.
Such connection pipes as pass through the boiler set-
tings should be protected by pipe sleeves two sizes larger
than the connection pipes. Pipe 14 in. in diameter is
commonly used for water-column connections, the duty be-
ing virtually the same for any size boiler. If the connec-
tions are more than 3 ft. in total length, the column should
be separately supported, and if separately supported the
individual connections should not be much shorter than
3 ft., in order to provide for the differences in expansion
of the boiler frame, front and connections.
Shown in Fig. 64 is a satisfactory method of piping a
water column. The pipe leading from the top of the col-
umn to the steam space of the boiler is connected into the
top of the boiler shell, or passes through the front breech-
ing in the horizontal tubular boiler, and enters the front
head above the point where it is desirable to carry the
water. The cross, C', has a connection leading to the
steam gage, E. In providing this connection, it is well to
arrange the pipe as shown, as the accuracy of the gage may
108
be tested at any time by attaching a test gage to the angle
valve, F.
From the cross, C, the water connection enters the
boiler head or drum head, one branch of the bottom outlet
taking the column blowoff connections, M, controlled by
the valve, L, to the ashpit.
It is considered good practice to remove the pet cock
that is usually sent with the lower water glass fittings and

-E
O STEAM SPACE
H
G-
PTO WAT
-TO WATER SPACE
M
·TO ASH-PIT
FIG. 64.
FLEXIBLE ARRANGEMENT OF WATER COLUMN
CONNECTIONS
connect in a nipple and valve, G, as shown, since a valve
opening permits a freer discharge from the gage glass.
This should be connected into the pipe from the column
blowoff and thus discharged into the ashpit. No connec-
tion other than the steam gage should be attached to the
column or its connections, as a draft of steam or water
through them will cause an erroneous reading of the water
level. Blowoff lines from the bottoms of the water column
and gage glass should run separately down to a point with-
in reach from the floor and a valve placed in each connec-
tion before it reaches the common discharge.
Valves H and I should be gate valves of the outside
screw and yoke type and in some localities it is specified
that these valves be locked or sealed open for normal oper-
ation.
One advantage of having valves H and I in the
109
water column connection is that it makes possible a more
thorough clearing of the water connections. Without
these valves there is no assurance that most of the blowing
out does not take place in the steam connection.
With the arrangement shown, the water connection may
be blown separately and therefore more effectively. This
is accomplished, first, by closing I and leaving H open.
Then with L open, the boiler pressure is concentrated on
the area of the water connection, and the pipe is thoroughly


FIG. 65.
FIG. 66.
BLOWOFF PROTECTED BY FIRE-BRICK SLEEVE
BLOWOFF CONNECTION WITH CIRCULATING PIPE
washed out. Next, valve H is closed and I is opened, which
will thoroughly clean the steam connection, then open H
and close L, restoring normal conditions.
BLOWOFF PIPING
For the proper removal of scum, precipitated scale-
forming materials and mud, every boiler is provided with
one or more blowoffs, and, in order that the boiler may be
completely emptied, it is necessary that the blowoff pipe.
should be connected at the lowest point of the boiler. For
general high-pressure service, the blowoff pipe should be
of extra heavy material and capable of withstanding from
175 to 200 lb. pressure.
Different methods are employed for protecting blow-
off pipe wherever it is exposed to the fire in the combustion
chamber. In most water-tube boilers, it is located well
away from the hottest part of the fire so that it is only nec-
essary here to consider the blowoff piping of a return tubu-
lar boiler.
Two common methods of arranging blowoff piping are
shown in Figs. 65 and 66. In the first instance, the de-
110
scending pipe is protected from the heat of the gases by a
sleeve of fire brick, although a V-shaped pier of fire brick,
with the point toward the front of the boiler, is sometimes
employed. The horizontal pipe is bricked over or covered.
with a coil of plaited asbestos rope-1/2 to 3/4 in. in diam-
eter. Figure 66 shows the bottom blowoff pipe provided
with a circulating pipe which enters the rear head of the
boiler. Where the blowoff pipe passes through the rear
wall of the setting, it should be surrounded by a sleeve, so
that it will be free to move. To prevent air leaking in, the
space between the sleeve and the pipe should be packed
lightly with asbestos rope or a similar substance without
interfering with the free movement of the pipe.
Diameters of blowoff pipes for tubular boilers are com-
monly as follows: 11/2-in. pipe for boilers up to 42 in. in
diameter; 2-in. pipe for boilers up to 60 in. in diameter,
and 22-in. pipe for larger boilers. In low-pressure and
water-tube boilers, the size of the blowoff is determined by
the manufacturer, a tapped boss at the lowest point in-
dicating the size of pipe to be used.
Several boilers may be connected to one common blow-
off header; and since, in general practice, but one boiler
is blown down at a time, the diameter of this header may
be only 3 or 4 in. All branches should connect to the
header by means of a "Y" to minimize resistance due to
mud, etc. It is advisable to design the blowoff branch lead-
ing from the boiler to the header so that the severe strains
due to extreme expansion and contraction will not affect
them. Short and rigid connections should be avoided and
all possible flexibility given.
1
Each blowoff line should be provided with a valve or
cock especially designed for this purpose, supplemented by
a gaie valve. On account of the rather severe service to
which they are subjected, blowoff valves are usually made.
extra heavy, with removable discs and seats. Globe valves
are never used because they do not readily provide a free
passage for the sludge and scale. When the boiler is blown
down, the valve next the boiler should be opened first,
then the outer valve is opened. In closing, this order
should be reversed, the valve nearest the boiler is closed
last. In this way the valve nearest the boiler remains in
good condition, prevents leakage and enables the outer
111
valve to be replaced if necessary without shutting down the
boiler. All fittings on the blowoff line should be of cast
steel.
SURFACE Blowoff
Boilers are frequently fitted with a surface blowoff,
which is simply a 1 or 12-in. pipe carried through the
shell or head with a bushing, and fitted with a funnel-

EJE0000
FIG. 67. SURFACE BLOWOFF PIPE
shaped opening, as shown in Fig. 67. This pipe is pro-
vided with a cock or valve, and serves to remove floating
impurities that would finally settle to the bottom of the
boiler if not removed.
BLOWOFF TANKS
In buildings in cities where it is not permitted to blow
down a boiler under steam pressure, discharging hot water
into the sewer, it is customary to provide a tank into
which the water is discharged and allowed to cool before
being run into the sewer. Figure 68 shows a tank con-
structed for this purpose.
Size of the blowoff tank depends upon the number of
boilers to which it is connected. In some plants, where 12
to 18 boilers are connected to one tank, the tank may be
from 5 to 6 ft. in diameter and from 6 to 8 ft. in height,
and made of rolled steel. In smaller plants, a horizontal
tank 3 ft. by 6 ft. is commonly employed.
Blowoff tanks should be provided with an overflow pipe
and a vent, which may discharge either directly to the
roof or to the atmospheric exhaust pipe; in some instances
it is connected to the auxiliary exhaust and discharged
through the heater. Where conditions permit, the tank
112
may be a pit constructed of brick or concrete. Frequently
the vent pipe is not sufficiently large, thus allowing steam
to be carried into the sewers, and also, since it fails to
relieve the pressure, permitting water to be discharged
through the vent.
SAFETY VALVES
All safety valves should be directly connected to the
highest possible point on the boiler and independent of
any other steam connection except the Y base forming the
OUTLET
F
ÈVENT. PIPE'

INLET
30301
FIG. 68. BLOWOFF TANK
support for twin valves. The area of the opening in the
boiler must be equal at least to the aggregate area of all
the safety valves connected to it, screwed connections
being permissible on low-pressure heating boilers only. No
shutoff of any description should be employed between the
safety valves and the boiler nor on the discharge pipe, if
such is used.
If the escape of steam becomes a nuisance, the outlet
of the safety valve may be piped to the atmosphere, in
which case the pipe so used must be of a diameter equal to,
or greater than, the diameter of the valve disc, and must
be properly drained to avoid the collection of water. If
the discharge pipe is of considerable weight, it should be
supported properly to relieve the valve body of any strain,
and when placed in a vertical position, a large radius bend
113
with bleeder attached to the lowest point to remove all
condensation should be used instead of an ell.
The safety valve drain should be free to the atmosphere
at all times to avoid damage due to condensation remain-
ing in the valve and causing water hammer when the steam
is escaping.
STEAM FOR STOKER PLUNGERS
For such stokers as are operated by a steam cylinder
directly connected to the stoker plunger, the steam supply
line should be run above the stoker cylinder and the ex-
T
HOLLOW.
STAY BOLTS
STRONG SUPPORI
UNION
QUICK OPENING
LEVER VALVE
TOP VALVE

CORD
HOSE
FIG. 69. STEAM CONNECTION FOR HAND SOOT BLOWER
haust line below, so that any condensation in the steam
line will be worked through the cylinder and out of the
exhaust.
SOOT BLOWERS
Another device which will be supplied from the boiler
room line is the soot blower, whether hand operated or
permanently installed. For a hand operated blower, the
outlet to which the steam hose is attached should have a
stop valve, then a strong support, to resist the strain from
moving the blower about, and a quick opening valve should
be provided at the inlet to the hose, with an operating
cord which can be carried with the blower, Fig. 69, in this
way controlling the admission of steam to the hose rather
than using a control valve at the blower end of the hose.
For the fixed type of tube blower, a stop valve should
114
be provided near the inlet to the nozzles, with a drip
ahead of it so that all condensation may be removed from
the line before operating the jets. There should, also, be
a stop valve as near as possible to the main, to keep con-
densation out of the branch to the blower.
Any water blown through the jets onto the tubes and
thus coming in contact with the soot is bad, as it cools

RED
www
TAN'
REC
TO BOILER
PUME
TRAC
||TO SEWER
ATMOS.
FLOOR
CONO
REL
FIG. 70.
ARRANGEMENT OF PIPING FOR COMPOUND STEAM
ENGINE JACKETS AND RECEIVERS
down the tubes and also, combining with the soot, sticks
the soot to the tubes and forms acids which will start
corrosion.
PIPE CONNECTIONS FOR STEAM ENGINES
In making the connection between the header and a
steam engine, the general rule is to make the pipe branch
as short and direct as possible using long sweeping bends
in preference to ells. Connection should be made at the
top of the header to avoid taking condensate into the
branch. A gate or angle valve should be located at the
highest point in the branch which is usually at the header
connection. The throttle valve is located at the engine
and requires a drip connection from the inlet side of the
disc. A steam separator may be located as shown in Fig.
70, or directly above the throttle valve, but always ahead
115
of any bypass connections to the receiver or low-pressure
cylinder. In cases where the pipe line from the boilers is
of considerable length, a separator of the receiver type will
tend to even out the pulsating steam flow and give better
operating conditions.
STEAM JACKETS AND RECEIVERS
For steam jackets of engine cylinders, and inter-
mediate receivers for compound engines, live steam should
be supplied at full boiler pressure, and this should be
taken from the pipe in such a way as to insure as dry
steam as possible. Water passed through cylinder jackets
or the heating coils of a receiver serves no useful purpose,
and simply clogs up the steam. As the condensation from
jackets and receiver coils will be at full boiler pressure and
temperature, it is desirable to collect this in a special tank
and return it direct to the boiler; but if the plant be small,
it may be better economy to waste a certain amount of
heat and send this water to an open feed heater or to the
hot well. Condensation from the steam separator on the
supply line to the engine may well be piped to the same
line as the condensation from jackets and receiver coils.
In piping up a compound or triple expansion engine,
provision must be made for operating the high-pressure
cylinder with the low-pressure cylinder non-operative, or
for supplying live steam at reduced pressure to operate the
low-pressure cylinder with the high-pressure non-operative,
in case there are three or less units in the plant. For more
than three units, it does not pay to install this com-
plication, as it is better to leave one unit entirely out of
commission and operate the plant with those which are
able to run until repairs can be made.
A branch should be taken from the exhaust connec-
tion between the high-pressure cylinder and the receiver,
to exhaust either into the condenser or to atmosphere,
with, of course, the proper stop valves to shut off this
branch during normal operation. The steam supply to the
receiver for operating the low-pressure cylinder alone
should be taken through a reducing valve which will cut
the pressure down to 25 lb. in the receiver, and should
have stop valves on both sides of the reducing valve so
that this may be isolated for overhauling. There should
116
be, also, a relief valve between the receiver and the low-
pressure cylinder, set to blow at 25 lb. pressure, to avoid
the possibility of high-pressure steam entering the low-
pressure cylinder. Long bends should be used in all con-
nections between the engine cylinders and the receiver, in
order to permit of expansion in the different pipe con-
nections. Straight-through connections are sure to result
in strains that will tend to open up the joints.

LOW PRESS
GLAND
TO OPEN
SEWER
TURBINE
CASING
POP VALVE
७
HIGH PRESS.
GLAND
STOP VALVE
STEAM MAINS
SEPARATOR
-THROTTLE VALVE
TO OPEN
SEWER
GOV.I
VALVE
TO TRAP
„TO TRAP OR SEWER
CIRCULATING
PUMP
DRY VACUUM
PUMP
TURBINE
TO HOTWELL
CONDENSATE PUMP
TO
ATMOSPHERE
OSPHE
ATMOSPHERIC RELIEF VALVE
·SURFACE ·CONDENSER
FIG. 71.
TURBINE PIPING, SHOWING ARRANGEMENT
VALVES AND AUXILIARIES FOR CONDENSING OPERATION
OF
In engines which have a device for working steam
through the high-pressure cylinder when starting up, the
receiver and low-pressure cylinder may be warmed in this
way; but if there is no such method, then provision should
be made for bypassing live steam at high pressure into the
receiver and low-pressure cylinder, in order to warm up the
engine before starting.
Each jacket should be supplied by an independent
branch from the steam line rather than by sending con-
117
densation from the high-pressure cylinder through the
jacket of the low-pressure.
TURBINE PIPING
Steam piping to turbines is essentially the same as
that to reciprocating engines, as will be observed in Fig.
71, except that perhaps more care is needed to prevent
strains of the piping system from being transmitted to the
turbine casing. Header and throttle valves and steam
separators are similarly located, but as the steam flow is
steady the receiver type of separator is not essential. The
higher steam velocities used in turbine installations make
doubly important the provision of pipe bends to cut down
friction.
With mixed pressure turbines the low-pressure inlet
must also be carefully drained and prevented from strain-
ing the turbine casing. In some cases a corrugated copper
expansion joint is used at the connection to the low-
pressure inlet. A similar joint is used in the connection
between the turbine and the condenser. A shutoff valve
in the turbine exhaust line is also found necessary in most
cases and between the shutoff valve and the turbine an
atmospheric relief or back pressure valve is needed to
protect the turbine casing from excessive pressure in case
the turbine throttle is opened when the exhaust shutoff
valve is closed.
Proper drainage of the turbine casing is highly im-
portant. Pipe taps for draining purposes should be pro-
vided in the throttle valve, in the high and low-pressure
valve chests, in the "bleeder" and low pressure inlet
diaphragms (if the machine is a bleeder or mixed-pres-
sure turbine), and in the exhaust end. These should be
connected to traps for automatic draining during the
operation of the machine and the piping so arranged as to
permit drawing off all accumulated water before placing
the unit in operation.
Turbine casings must be provided with packing glands
around the shaft at both steam and exhaust ends.
These
require either water or steam for sealing purposes and in
either case must be connected up to the supply with a
valve to control the flow to the gland.
118
CONDENSER PIPING
In independent condensing systems, the condenser
should be placed below and as near the engine or turbine
as possible, in order to allow the exhaust steam to gravitate
toward it. Bends and joints should be reduced to a mini-
mum to decrease friction and the possibility of air leakage,
and where a change in direction of the piping is neces-
sary only long-sweep bends of cast iron or steel should be
employed.
Local conditions may necessitate placing jet or surface
condensers on the same level as or above the engine or
turbine, requiring the use of additional piping. In this
case, the lowest point of the exhaust should be fitted with
a drip which should be open whenever the engine is not
operating. Centrifugal condensers like those of the ordi-
nary jet type are preferably connected as directly and
closely as possible to the engine or turbine.
In high vacuum systems, for steam-turbine practice,
the turbine is mounted directly over the condenser, the
steam connections being joined by a short copper corru-
gated expansion joint.
Barometric condensers due to being, as a rule, installed
at a considerable height, require the use of an exhaust riser
which should be joined to the horizontal exhaust line by
means of an extrainer. The exhaust line should be given
a pitch of about 1 in. in every 20 ft.
One of the most important precautions required in the
design of condensers of the jet type is to place the exhaust
steam inlet some distance above the point of injection
water discharge so as to avoid the possibility of flooding
the engine or turbine.
CONDENSER SYSTEMS
Two general schemes of condenser installation are em-
ployed, namely, the independent or subdivided system and
the central system. In the former, that confined prin-
cipally to central stations and those plants having large
turbines, each unit is provided with its individual con-
densing equipment; in the central system, particularly
well adapted where the exhaust steam is used for heating
and the requirements are more or less variable, one con-
denser suffices for all engines, connections being such that
}
1 19
the entire plant, or any part of it, may be operated either
condensing or noncondensing.
Water for condensing purposes may be obtained from
a nearby stream, lake, well or the local water system, in
which case, however, there may be some question as to the
saving in installation and operation justifying the expendi-
ture necessary for the added equipment.
Local conditions permitting, the water is generally
allowed to flow by gravity through tile, concrete or iron
intakes into a cold well or cistern located in the power
house as near the condensers as possible. With the plant
at a considerable elevation above the source of supply and
where elevated jet or barometric condensers are employed,
these may be placed so as to allow the exhaust to drain
into the condenser; in the case of a surface condenser
installation, a sealed circulating-water system discharging
into the source of supply will act as a syphon, thus reduc-
ing the circulating pump head to friction and velocity
only.
Screens placed in the intake to prevent the entrance of
leaves, fish, sticks, ice, etc., are usually made of iron mesh
or bars with openings the same size as condenser tubes
or 1 in. smaller; these are set in frames operating in
slides for cleaning purposes and are enclosed in cast-iron
or concrete screen boxes or cribs. A late development for
use in large plants consists of self-moving screens arranged
either drum fashion or like a chain grate set on end. The
velocity through screens should not exceed 4 to 5 ft. per
second.
As a measure of precaution against possible shutdown
due to a shortage of condensing water, a city-supply con-
nection to the cold well is recommended.
JET CONDENSERS
Jet condensers may be installed either as shown in Fig.
72, or elevated. With the former arrangement, the engine
exhaust may pass through the feed-water heater and either
to the condenser, the heating system or the atmosphere; or
by means of the bypass the heater may be cut out for
cleaning and repairs.
Injection and discharge-line sizes are largely fixed by
the sizes of their respective connections in the condenser
120
shell, which for the former are generally based on a velocity
of water flow ranging from 400 to 600 ft. per minute and
that of the discharge pipe on velocities of from 200 to
400 ft. per minute. With an allowable velocity of 600 ft.
per minute, Marks' Mechanical Engineers' Handbook rec-
ommends making the discharge pipe diameter equal to
0.0765 times the square root of the number of pounds of
steam condensed per hour and that of the injection pipe

FIG. 72.
HAUST
FREE EXHAUS
EXHAUST
BY PASS
F.W.
HEATER
+O+
IRELIEF
VALVE
STEAM
HEATING MAIN
-OIL SER
COOLING
WATER
PIPING DIAGRAM FOR JET CONDENSER IN CONNEC-
TION WITH FEED-WATER HEATER
equal to the diameter of the discharge pipe, minus 1 for
small condensers, and minus 2 for large sizes.
If, due to the condenser being too large for its work,
a reduction in injection and discharge pipe size is advis-
able, this should always be made by means of tapering
reducers; never use bushings.
BAROMETRIC-CONDENSER CONNECTIONS
As barometric condensers depend upon the use of a
barometric column for the removal of condensate, cooling
water, and sometimes the entrained air and other noncon-
densible vapors, it is essential that the mixing cone be at
least 34 ft. above the high-water line in the intake, or
hot well, if such be used, allowing the height of the con-
denser as leeway to prevent flooding.
121
DISCHARGE
MANHOLE
INJECTION PIPE
Injection water and tail-pipe diameters are found in
the same manner as for jet condensers, and as in these rela-
tive location of injection water and exhaust steam inlets

RELIEF VALVE,
GATE VALVE-
AIR PUMP SUCTION
TAIL PIPE
MIXING
CHAMBER
EXTENSION STEM
HAND WHEEL
TO OPERATE
FROM FLOOR
ENGINE
EXHAUST
AIR VENT
DRAIN WITH
SWING CHECK
HOTWELL
FIG. 73. TYPICAL BAROMETRIC CONDENSER INSTALLATION
varies considerably, some builders place the former above
the latter, while in others the steam is introduced above
the cooling water inlet, either through an opening at the
side of the shell or directly through the top.
GALV. CABLE
RELIEF VALVE WATER
SEAL SUPPLY
122
The injection pipe should be fitted with a valve to
control the flow of water, and to prevent the entrance of
leaves, sticks, small fish, etc., it is desirable to provide it
with a strainer of ample size.
Installations in which the mixing cone is more than
20 ft. above the source of injection supply will require
pump; where less than 20 ft., the vacuum created in the
condenser will be sufficient to raise the injection water,
if some form of forced injection is provided for starting.
This may be accomplished also by running a horizontal
line fitted with a gate valve from the injection water line.
to tail pipe, the water flowing through this connection
and down the tail pipe, gradually exhausting the air from
the upper part of the tail pipe until sufficient vacuum is
created to draw the water up to the mixing chamber.
When this is established, the valve in the cross connection
is closed.
As few fittings as possible should be used on the tail
pipe, and if for any reason a change of direction is nec-
essary, long-sweep bends should be employed. The hot
well, if such is used, should have a volume of at least four
times that of the tail pipe; this should be sealed by at
least 18 in. of water above the outlet, which in turn must
clear the bottom of the well by 6 in.
Base ells on exhaust and injection risers will provide
sufficient support for condensers up to about 10 to 12 in.,
the whole outfit, however, being braced to a nearby wall
by A braces. For larger units, special provision must be
made for the support of the tail pipe, either by means of
a tripod attached to the base flange or some form of special
fitting supported by I beams stetched across the top of the
hot well. In no case should a base ell or any other sort be
used in the tail pipe.
The diameter of the air or dry vacuum connection may
be made 1/3 that of the tail pipe for 26 to 27-in. vacuums,
to be increased slightly for a 28-in. vacuum.
SURFACE-CONDENSER CONNECTIONS
In the scheme of piping connections for a small sur-
face-condenser installation shown in Fig. 74, the valve
arrangement is such as to permit the exhaust steam to
pass through the condenser, into the heating system or out
123
to the atmosphere. Water for boiler-feed purposes is taken
from the hot well and passed through a feed-water heater
supplied with steam from the auxiliary pumps.
Cooling water is usually introduced at the bottom of
the shell and caused to leave through an outlet on top, the
size of these connections being figured for a velocity of
8 ft. per second; the air connection area should be at least
twice that of the hot-well pump suction, which should be
figured for about 4 ft. per second.

FREE
EXHST
FREE
EXHST
B.PV
STEAM
FEED T
JFW HEATER
OIL SEP.-
PUMP
EXH
HOTWELL
)B.P.V.
HEATING'
MAIN
COOLING
WATER
FIG. 74. PIPING ARRANGEMENT FOR SURFACE CONDENSER
While small condensers of the surface type are gen-
erally mounted upon a combined steam-driven circulating
and condensate pump, those used in connection with large
generating units are supported by the main foundation
and are served with circulating water from a general sys-
tem instead of individual pumps, valves being provided
to shut off the flow of water to allow cleaning and repair-
ing the condenser.
DRY-VACUUM PIPING
This should always be connected at the highest point of
the condenser, and where a number of dry-vacuum pumps
serve a like or greater number of condensers interchange-
ably, a dry-vacuum main is necessary. This should pitch
slightly toward the air-pump openings wherever possible
to prevent the accumulation of condensation, and should be
tapped at the top for the condenser branches and at the
bottom for the pump connections, thus insuring the re-
moval of condensation in small continuous amounts. To
avoid the possibility of the pump branch filling with water,
124
a valve should be placed in this line directly below the
main; valves on the main between the various pump
branches will permit sections of the main being cut out
for repairs without interfering with the operation of the
plant.
Gate valves having a diameter no less than 1/4 that of
the pump suction and attached as shown at A, Fig. 75,
permit bringing the pump up to speed before taking full
vacuum.

TO CONDENSER
Похо
TO CONDENSER
FIG. 75.
VACUUM PUMPS
ARRANGEMENT OF DRY VACUUM MAIN WITH CON-
DENSER AND PUMP CONNECTIONS
After the pump is in operation, the branch line valves
should be opened slowly to permit water accumulated above
them to leak past and through the pump.
Hot wells located in engine rooms and boiler rooms
should be ventilated as shown in Fig. 73, and to prevent
the discharge of foul gases and vapors, manhole covers
and the tail pipe should have an air-tight fit at the top
of the well.
!
CHAPTER XII
PIPING FOR EXHAUST STEAM HEATING
SYSTEMS
As
S SHOWN in the scheme of connections of typical
exhaust heating installation, Fig. 76, exhaust from
the prime movers may be piped direct to the feed-water
heater, the system taking all surplus steam except during
the warm months when this, if not required for other
purposes, is diverted to the atmosphere through a back-
pressure relief valve. This should be placed above the
highest distributing main and in order to allow repairs
without interfering with the operation of the system, a
bypass and necessary cutout valves are frequently provided.
In addition, a pressure-reducing valve taking steam
from the high-pressure service should be installed for
emergency as when the exhaust is insufficient to meet de-
mands during severe weather or may be entirely unavail-
able. This also should be provided with bypass and cutout
valves.
The exhaust line to the heating system should be pro-
vided with a large oil separator placed next to the main.
system control valve and fitted with either a water seal
or a trap in the sewer discharge.
The mains with their connecting branches must have
a uniform pitch of about 1 in. in every 10 ft., and wher-
ever possible, should feed the radiators by means of the
"overhead" or "down-feed" principle. Where necessary to
make a reduction in size, eccentric fittings only should be
used and, if necessary to pass obstructions, resulting in
the formation of pockets, drips should be provided at such
points.
A pitch of 1 in. in every 30 ft. will prove satisfactory
for wet or dry returns.
Horizontal branches feeding risers should be no longer
than about 30 in., thus necessitating carrying the mains
from 2 to 3 ft. from the basement walls if the radiators on
the upper floors are to be placed along outside walls.
126
RETURN RISER
HEATING
RISER
OPEN VENT
то
ATMOSPHERE |
SUPPLY PRESSURE
GAVE
RETURN
PRESSURE
CAGE
FLOAT OPERATED
AUTOMATIC VALVE. COLD, WATER
AIR SEPARATING.
VENT To
ATMOSPHERE
TANK
HEATING MAIN,
OVERFLOW
TO SEWER
LIVE STEAM SUPPLY.
SUPP
FROM HEATING
MAIN TO
PRESSURE
REDUCING VALVE
VAC.
GOV.
TO DRAIN
OR TO
DRIP-
WATER SEAL
VACS
LINE
WATER LEG
COLD WATER
SUPPLY
"DIS. FROM
PUMP TO
TANK
RETURN
MAIN
BY-PASS TO SEWER
EXH.
DRAIN
BY PASS·
LIVE STERN SUPPLY
TO HEATING MAIN
PRESS. RED. V.
ΈΧΗ. ΤΟ
HTG. MAIN
"AUTOMATIC VALVE
OIL SEPARATOR
EXHAUST, STEAM
PY:PASS
BACK-PREIS
KAM-
CREASE TRAP
TO B.F. PUMP
SUCTION
DRIP
EXH, FROM ENGINE
TO SEWER
GREASE TRAP
FIG. 76. TYPICAL EXHAUST STEAM HEATING CONNECTIONS
WASTĘ EXH. TO ATM.
should be provided every five or six stories.
Where risers are of considerable length, expansion loops
to the feed-water heater by means of a pump, ejector or
ceiver, whence they are returned to the boilers or delivered
Returns generally terminate in some form of drip re-

127
condenser. The speed of the pump, if such is employed,
may be controlled by a vacuum governor mounted on a
bypass of the steam supply line of the pump with a con-
nection to the return main carrying a vacuum gage.
In the vacuum system illustrated in Fig. 76, an air
separating tank is employed between the vacuum pump
and heater. This is provided with a vent open to the
atmosphere, an overflow to the sewer and an automatically-
operated float valve for the control of makeup water which
may be introduced at this point of the system.
SIZE OF MAINS AND RETURNS
Required size of steam heating mains may readily be
determined by means of the curves shown in Fig. 77.
Assume we have a heating system to be operated at 5
lb. pressure and containing 10,000 sq. ft. (3000 lb. steam
per hour) direct radiating surface, and that the required
size of supply main is desired; allow a pressure drop of 1
oz. per 100 ft. of straight smooth pipe. At 10,000 sq, ft.
radiating surface on the horizontal axis, read vertically
upward to the 5-lb. pressure line; this is intersected be-
tween the 6 and 7-in. pipe-diameter line, therefore requir-
ing the use of a 7-in. pipe. Reading from this point to
the velocity axis at the left, the approximate velocity is
found to be 65 ft. per sec.
To find the size of return mains, allowing a pressure
drop of 1 oz. per 100 ft., divide the number of square feet
direct radiating surface by the constant in the following
table corresponding to the per cent of steam in returns and
refer the equivalent radiation so found to curves, Fig. 77.
Wet 212% 5% 72% 10% 15% 20% 25%
Steam Steam Steam Steam Steam Steam Steam Steam
40 20 13.33 10
5.71 4.44 3.64
If, in the above problem, it is required to determine
the size of return mains and 10 per cent steam is necessary
to maintain dry returns, we find, using constant 8 in the
above table, that the equivalent radiation is equal to 10,000
divided by 8, or 1250 sq. ft.
8
Referring to curves, Fig. 77, at 1250 sq. ft. radiating
surface and reading upward to the atmospheric pressure
line, we find the intersection of these between the 3 and
312-in. pipe line, thus calling for a 31/2-in. return.
128

O
100
90
80
2 2
TO
60
50
40
VELOCITY OF STEAM, FEET PER SEC.(FOR 1 OUNCE DROP IN PRESS. PER 100 FT.OF PIPE)
30
20
10
YO
9
12
15
18 21
3
7
SQ. 9 9 10
STEAM FLOW, 10 LB. PER HOUR
24 27 30
100 SQ FT DIRECT RADIATING SURFACE
60
90
120
150 180
(1 SQ. FT.- 3LB. PER HR)
8
210 .40 210 300
600
150
20
30
40
50
60
TO
80 90 100
200
250
100
90
8 3 8
૧
·ATMOSPHERIC PRESSURE
+5 LB. GAGE PRESSURE
PIPE
3D
PIPE
15 LB GAGE PRESSURE
10LB.GAGE PRESSURE
PE
PIPE
50
40
.
30
20
Ters
4
S
6 7
8 9 10
20
50
40
50
60
70
80 90 100
200
250
3
6
9
12
15
18
100 SQ.FT. DIRECT RADIATING SURFACE
21 24 27 30
60
STEAM FLOW. 10 LB. PER HOUR
(1 SQ. FT. - 3LB. PER HR.)
90
120
150
180
210 240 270 300
600
750
FIG. 77.
CHART FOR DETERMINING THE SIZE OF STEAM HEATING MAINS
1

UNIVERSITY OF MICHIGAN
3 9015 00287 9065