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Milk Product

A §UIDE FOR EVALUATING SANITARY CONSTRUCTION
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1964

U.S. DEPARTMENT OF
HEALTH. EDUCATION. AND WELFARE

, . LIE) Public Health Service I. Hf) I“"?‘” IQIIQ ,

  

 

 

 

 

 

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Milk and
Milk Product
Equipment

A GUIDE FOR EVALUATING SANITARY CONSTRUCTION

 

 

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE

L“\ i Public Health Service ' . 7 1’ '7 xi}

Dlvlslon of Environmental Englneerlng and Food Protection
Milk and Food Branch

Washington. 0.6. 20201

For sale by the Superintendent of Documents, U.S. Government Printing Oiflcc
Washington, I),C., 20402 - Price 15 cents

PUBLIC HEALTH

FOREWORD

This guide, developed by the Milk and Food Branch, Division of
Environmental Engineering and Food Protection, US. Public Health
Service, is designed to assist milk regulatory officials in evaluating
milk and milk product equipment for compliance with the Pasteurized
Milk 0rdinance—Recommendations of the Public Health Service
and the US. Public Health Service Frozen Desserts Ordinance and
Code. The 3—A Sanitary Standards for the design and construction
of dairy equipment, promulgated by the 3—A Sanitary Standards
Committees, have provided valuable resource information in the
development of this guide.

311

a.

CONTENTS

Page

Section A. Definitions _______________________________________________ 1
Section B. Materials ________________________________________________ 1
Section C. Fabrication Criteria, General _______________________________ 2
Section D. Fabrication Criteria for Specific Types of Equipment _________ 10
1. Fillers and Sealers ___________________________________________ 10

2. Batch Pasteurizers and Processors _____________________________ 11

3. Storaxze Tanks ______________________________________________ 14

4. Automotive Transportation Tanks ____________________________ 15

5. Evaporators and Vacuum Pans _______________________________ 16

6. Equipment for Supplying Air Under Pressure ___________________ 17

7. Product Pumps _____________________________________________ 19

8. Batch and Continuous Ice Cream Freezers _____________________ 21

 

A. Definitions

1. Product—Shall mean milk, milk products, and frozen dessert
mixes.

2. Product Contact Surface—Shall mean all surfaces that, are ex—
posed to the product, or from which liquid may drain, drop, or be
drawn into the product, or container and surfaces that touch product
contact surfaces of containers.

3. Nonproduct Contact Surfaces—Shall mean all other exposed
surfaces.

4. Easily Accessible—Shall pertain to areas of surfaces that. can be,
exposed for cleaning and examination without the use of tools.

5. Readily Demountable Farm—Shall mean those parts that can
be disassembled or removed without the use of tools.

B. Materials

1. Product Contact Surfaces

All materials shall withstand, under the environment of their
intended use, the action of all dairy products, all washing compounds,
and accepted sanitizing agents within reasonable limits. They shall
be nontoxic, corrosion resistant, relatively nonabsorbent, and shall not.
impart flavor or odor to the product, and shall maintain their essential
properties under repeated use conditions.

a. Metal—Shall be stainless steel of the American Iron & Steel
Institute (A181) 300 Series or equally corrosion resistant metal that
is nontoxic and nonabsorbent and will withstand, under the environ-
ment of its intended use, the action of all dairy products, all washing
compounds, and accepted sanitizing agents within a reasonable limit.

1). Plastic and Rubber and Rubberlike Malaria/.m—Shall be rela—
tively inert, resistant to scratching, seonring, decomposition, erazing,
chipping, staining, and distortion under normal use conditions; shall
be nontoxic, fat resistant, relatively nonabsorbent, and shall not impart.
flavor or odor to the product; and shall maintain their essential prop-
erties under repeated use conditions.

NOTE: Plastics conforming with the “3—A Sanitary Standards for Multiple-Use
Plastic Materials Used as Product Contact Surfaces for airy Equipment."
Serial No. 2000, conform to these characteristics. Rubber and ruhherlike ma-
terials conforming with the “3—A Sanitary Standards for Multiplevfse Rubber
and Rubberlike Materials Used as Product Contact Surfaces of Dair.v Equip-
ment,” Serial No. 1800. conform with these characteristics.

0. Glass and Ceramic Material—Shall be resistant, inert, insoluble
and nontoxic, and resistant to distortion by the temperature, chemicals,
and methods to which it. is normally subjected in operation, cleaning,
and sanitizing.

d. Welded or Brarzed Areas—The deposited weld or braze material
shall be substantially as corrosion resistant as the parent material.

2. Nonproduct Contact Surfaces

Shall be of corrosion resistant material, or material that is ren-
dered corrosion resistant or painted. All nonproduct contact surfaces
shall be relatively nonabsorbent, durable, and cleanable. Parts remov-
able for cleaning having both product and nonproduct contact surfaces
shall not be painted.

C. Fabrication Criteria, General

All equipment shall be so designed as to be capable of performing
its intended function and so that it can be operated in a sanitary man-
ner; the design shall include such sanitary safeguards and appurte-
nant indicating, regulating, and control devices as are necessary to
safeguard the public health (refer to Public Health Service Milk Ordi-
nance for appropriate details). The following requirements shall also
be met:

1. All product contact surfaces shall be finished to the equivalent of
a No. 4 mill finish on stainless steel or better.

2. All permanent joints in metallic product contact surfaces shall be
welded or brazed.

3. Solder may be used for functional reasons such as blade mounting
pins, shafts, bushings and bearings for flushing joints and producing
fillets for minimum radii where welding is impracticable. Solder
when used shall have a tin content of not less than 50 percent and shall
contain no more lead than is necessary under good manufacturing
practices.

4. All internal angles of 135° or less on product contact surfaces
shall have a minimum radii of 1/4 inch (fig. 1), except that: smaller
radii may be used when required for essential functional reasons such
as filler nozzles, sealing ring grooves, and other assemblies of machine
parts which are readily demountable for cleaning and inspection.

5. All product contact surfaces shall be easily accessible and readily
cleanable, either when in an assembled position or when removed.
Removable parts shall be readily demountable.

6. All product contact surfaces shall be self-draining.

7. The bottom of all tanks, vats, filler bowls, and hoppers shall slope
toward the outlet(s). Bowl bottoms shall have a minimum slope of
1A; inch per foot.

8. The junction of the vertical sides of a vessel with the breast and
with the bottom shall be moisture and vermin proof.

9. All openings in covers of equipment shall be equipped with sani—
tary fittings or shall have raised rims or flanges of at least 3/8 inch, and
such openings shall be provided with removable covers having a down—

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FIGURE 1

ward flange of not less than 14 inch so designed as to prevent liquid
from entering the product zone (fig. 2).

10. Covers shall be self-draining and closefitting, and shall have a
downward flange overhanging the rim of the vat, bowl, or hopper by
at least 9/8 inch.

11. Covers, diverting aprons, shields, or guards shall be provided
whenever needed to prevent liquid or other contaminants from drain-
ing or dropping into the product, the product container, or onto prod-
uct contact surfaces (fig. 3).

12. Agitator shaft openings through the bridge or top enclosure
shall have a minimum diameter of 1 inch for agitator shafts which re-
quire removal for cleaning, or be of a diameter that will provide 1-
inch minimum annular cleaning space between the agitator shaft and
the inside surface of the flanged opening for agitators which do not
require removal for cleaning. A shield that can be raised or dis-
mantled, to permit the cleaning of all its surfaces, shall be provided
to protect against entrance of dust, oil, insects, and other contaminants

738—847 0—64—2 3

1/4" OVERLAP
3/8" LIP

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FIGURE 2

into the product zone through the annular space around the agitator
shaft (fig. 3).

13. Top ente1 111g nomeinovable agitator shall be readily accessible
and clcanable. There shall be at least a 1/2- -inch space between the
nonremovable agitator and the bottom of the lining, unless the agitator
is mounted on a hinged-type cover.

14. Top entering removable or demountable agitator shall be pro—
vided with an easily accessible, readily demountable coupling of either
a sanitary type located within the lining or a coupling located outside
of the lining, provided that it is above the shield provided to protect
the annular space around the shaft. All product contact surfaces of
the. 1111itatox shall be \isible \\ hen the agitator is removed. A bottom
suppoit or (1 aide, if used, shall be welded to the lining, shall not inter-
im with drainage, and the inside angles shall have minimum radii
of1 g inch \Vlien the agitator shaft has a bearing cavity, the diameter
of the cavity shall be greatei than the depth. The agitator shall be
easily demountable foi cleaning of the bearing and any shaft cavity.

11 1. Side o1 bottom agitat01 and shaft, including the complete seal,
shall be 1eadil_\ dentonntable for cleaning. Nonremovable parts hav-
ing product contact surfaces shall be designed so that the product
contact surfaces are readily cleanal)le from the inside of the vat.
Seals for the agitator shaft shall be of a packless type, sanitary in de-
sign. with all parts readily accessible for cleaning.

11;. (‘overs ol’ the type which may be opened shall be so designed
that when raising the cover, any liquid 011 the top will not enter the
product zone. When covers are in their fully opened position, the
drops ot‘ condensate formed on the underside of the cover shall not
drop into the product zone. (,‘overs should be provided with adequate
conveniently located and durable handles of sanitary design (fig. 4).

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FIGURE 6

17. The edges of inlet openings for sanitary piping shall extend
upward or outward at least 3/8 inch (fig. 5) or be fitted with a perma-
nently attached sanitary fitting at least equal to the criteria set forth
in the “3—A Sanitary Standards for Fittings Used on Milk and Milk
Product Equipment and Used on Sanitary Lines Conducting Milk
and Milk Products,” and supplements thereto.

18. The covers for a manhole located in the sidewall of equipment.
shall be the inside or outside swing type. If the cover swings inside,
it shall also swing outside, away from the opening, for disassembly
and cleaning. Threads or ball joints employed to attach the manhole
cover(s) and its appendages shall not be located within the lining.
If mounted on top of the equipment, manhole cover(s) shall be of the
outside swing type.

19. Manhole openings shall be not less than 15 by 20 inch oval,
12 by 27 inch elliptical, or 18-inch diameter, except that equipment
using manholes and having a capacity of 300 gallons or less may have
a manhole with a diameter of not less than 16 inches.

20. Equipment shall be so designed that adjustments necessary dur-
ing the operation can be made without raising or removing any cover.

21. There shall be no threads used on product contact surfaces
except where needed for functional or safety reasons as in clarifiers,
pumps, and separators. Such threads if used shall be of a sanitary
type. The threaded angles shall be not less than 60° and with not
more than eight threads per inch, nor less than 5/8-inch major basic

diameter. The length of the nut shall not exceed three-fourths of the
basic major diameter and the nut shall be of the open type (fig.
6).

22. Sight and light openings shall be of such construction that the
inner surfaces drain inwardly or shall be relatively flush with the
inside surface, and the transparent plastic or glass shall be removable
for cleaning. The diameter of the opening(s) shall be not less than
3% inches and shall be so constructed as to assure adequate circulation
and agitation in the sight openings.

23. Legs shall have closed bases. Exterior of legs and leg sockets
shall be readily cleanable.

24. Legs or other supports shall be such that a 6—inch minimum
clearance will be provided between the floor and the bottom of the
equipment 72 inches or less in diameter or width or an 8-inch mini-
mum for equipment more than 72 inches in diameter or width, except
that movable equipment with legs and/or casters may have a clearance
between the lowest fixed point of the equipment and the floor of not
less than 4 inches when the base outlines an area in which no point
is more than 121/2 inches from the nearest edge.

25. Any coil spring having product contact surfaces shall have at
least 3/32-inch openings between the coils, including the ends.

26. Gaskets shall be removable or be permanently bonded. Gasket
retaining grooves for removable gaskets shall be no deeper than their
Width. The minimum radius of any internal angle in a gasket re-
taining groove shall be not less than 1A; inch, except that a 3/32-inch
radius is permissible where a standard 14-inch O-ring is to be used.

27. Thermometer connections and openings shall meet criteria at
least equal to those in the “3—A Sanitary Standards for Thermometer
Fittings and Connections Used on Milk and Milk Product Equip-
ment,” and Supplement No. 1 thereto (fig. 7). Button~type thermo-
couples attached to the outer side of a tank lining are permissible.

28. All air used in contact with product or product contact surfaces
shall conform to criteria at least equal to the “3—A Accepted Practices
for Supplying Air Under Pressure in Contact with Milk, Milk Prod-
ucts and Product Contact Surfaces”; clamp fittings shall not be
permitted in the product zone.

29. Tubing and related fittings, within a tank or vat, which are
used for mechanical cleaning or air agitation shall be readily and
easily demountable and removable for cleaning outside the tank or
vat or designed for mechanical cleaning-in—place.

30. Mechanical cleaning systems for vats and tanks shall be so
designed that the solution is applied to all product contact surfaces
except those areas requiring manual cleaning, including vents, valves,
manholes, and gaskets. If designed for cleaning-in-place, the tubing
and all related fittings shall be self-draining.

 

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THERMOMETER FITTING

FIGURE 7

31. Strariners.—(a) Shall not be made of wire or woven material.
(6) shall be made of perforated metal, and (c) perforations or slots
shall not be less than 3"“ inch in diameter and the end radius of the
slots shall be not less than 3;“; inch.

D. Fabrication Criteria for Specific Types of Equipment

Certain types of equipment require special consideration in their de-
sign and fabrication. The purpose of this section is to identify these
specific items not included or adequately covered in section C.

1. Fillers and Sealers

a. Steam defoamer systems shall be provided with a suitable self-
draining water condensation trap and strainer on the steam line just
prior to the defoamingr head (fig. 8). The steam shall be of culinary
quality. (See Appendix G, Part IV, Pasteurized Milk Ordinance—
Recommendations of the Public Health Service.)

I). The defoamer heads shall be constructed of stainless steel or other
equally corrosion resistant metal and shall be readily demountable and
disassembled for cleaning.

10

SELF DRAINING WATER CONDENSATION TRAP

  
     
 
  
 
 
  

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FIGURE 8

0. Vacuum systems designed to remove foam continuously shall be
so designed that all surfaces from which foam may drain, drop, or be
drawn into the product are easily accessible, visible, and readily clean-
able, either when in an assembled position or when removed. Remov-
able parts shall be readily demountable (figs. 9 and 10).

2. Batch Pasteurizers and Processors

a. Inside angles of batch pasteurizers and processors shall have mini-
mum radii of 1/2 inch.

1). The bottom lining shall have a minimum slope of 3/8 inch per foot.

0. Plastic and rubber and rubberlike materials may be used for
measuring devices, slinger or drip shields, agitator seal on vacuum
and/or pressure processors or pasteurizers, agitator bearings, pro-
tective caps for openings (other than manhole) and/or for sanitary
fittings, scrapper blades, gasket, seals, and parts used in similar appli-
cations. Plastic materials may be used for sight and light parts.

d. All accessories, bridges, or appurtenances which are welded to

H

VACUUM DEFOAMER SYSTEM

CONTINUOUS RETURN TYF’E

Surfaces down stream
from this elbow shall
be consideved non—prod—

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FIGURE 9

the lining, and which have inside angles of less than 135°, shall have
minimum radii of 14 inch.

9. The outlet, the flare of batch pasteurizers and batch processors,
and the outlet valve of batch pasteurizers shall conform to the design
and construction provisions outlined in appendix G, part II, of
the Pasteurized Milk Ordinnnce—Recommendations of the Public
Health Service.

f. The outlet and outlet valve shall be designed so that either a
single service or a multiple—use gasket can be used.

9. The outlet valve shall be removable for cleaning and shall be
considered removable when secured by not more than four hex nuts.

k. The agitator driving mechanism on top—mounted agitators shall
be securely mounted in a position that will provide a minimum distance
of 4 inches measured vertically downward to the bottom of the driv—
ing mechanism housing, excluding bearing bosses and mounting bosses,
to the nearest surface of the pasteurizer or processor and in such a man-
ner that all surfaces of the pasteurizer or processor under or adjacent
to the driving mechanism shall be readily accessible for cleaning and
inspection (fig. 11).

2'. Mechanical cleaning shall be provided in pasteurizers and proc-
essors, the inside height of which exceed 96 inches.

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FIGURE 11

j. The airspace heater shall be mounted Within the space between
the top enclosure, cover, or bridge of pasteurizers, and the level of
the product when the pasteurizer is filled to its rated capacity (Ap-
pendix G, Part II, Pasteurized Milk Ordmalice—Recommendations
of the Public Health Service). Only sanitary fittings conforming
to construction and design criteria at least equal to those in the “3—A
Sanitary Standards for Fittings Used in Milk and Milk Products
Equipment and Used on Sanitary Lines Conducting Milk and Milk
Products,” and supplements thereo, shall be used.

Is. A warning plate furnished and permanently affixed by the manu—
facturer shall be provided for closed-type pasteurizers and processors
which shall indicate the maximum operating pressure and /or vacuum
conditions under which the pasteurizers or processors may be safely
operated. A statement on the nameplate or on the warning plate, or
on a plate furnished and permanently affixed by the manufacturer,
shall identify the equipment as either a processor or a pasteurizer.

3. Storage Tanks (Including Silo Type)

a. Silo—type tanks and transportation tanks shall have minimum
radii of 1% inch where head and bottom, or ends, join the sidewalls.

b. The bottom lining of silo-type tanks shall have a minimum slope
of 34 inch per foot.

0. The control area of a silo-type tank shall be that part of pas-
teurizing, processing, cooling, or packaging area or storage tank gal-
lery room in which all appurtenances for the operation of the silo
tank are located and vent lines terminated.

d. When a silo tank is located outside of the pasteurizing, process-
ing, cooling, or packaging area or storage tank gallery room or is not
adjacent to the outside wall of one of these areas, a hallway shall be
constructed at least 7 feet high and 5 feet wide to provide access to
the control alcove (in this case also the control area).

6. All openings through a silo tank lining shall be within the con-
trol area, except openings for mechanical agitators and openings for

14

cleaning and/or vent lines. Cleaning and/or vent lines shall termi-
nate in the control area.

f. Means shall be provided for mechanical and/or air agitation of
the product, and such agitation shall be operated intermittently or
continuously and shall be sufficient to maintain the butterfat content
of whole milk throughout the tank within plus or minus 0.1 percent.

9. In silo tanks, means shall be provided for mechanical cleaning
the product contact surfaces of the tank, piping, and all nonremovable
appurtenances thereto.

h. Outlet valves shall be close-coupled, sanitary-plug type or close-
coupled compression type with no stuffing box.

4. Automotive Transportation Tanks

a. Interior attachments of transportation tanks shall have minimum
radii of 1/16 inch.

6. The outlet valves shall be close-coupled, sanitary-plug type or
close-coupled compression type with no stuffing box.

0. The valve outlet shall be equipped with a sanitary cap to cover
all threads when in place.

(1. The entire valve assembly shall be encased in a cover which shall
be dustproof and tamperproof. If the valve is in a dustproof cabi-
net, then the dust cover over the valve is not necessary.

6. Manholes shall be so located that in no case shall either end of
the tank be more than 18 feet 6 inches from a manhole opening.

f. Each manhole shall be provided with a dust. cover. The interior
finish of the dust cover shall be smooth, readily cleanable, and free
from bolts or screws. Means shall be provided to relieve vacuum and
pressure when the tank is being emptied or filled, and shall be so con-
structed and operated as to protect the milk from dust, insects, and
other contamination.

g. Permanently mounted air or mechanical cleaning solution tubing
shall be constructed and installed so that it will not prevent complete
drainage of the tank or tubing, and shall be located so that the dis-
tance from the outside of the tubing and the tank lining shall be
at least 2 inches.

h. Transportation tank baffles Shall be welded to the tank and the
radii where the baffle attaches to the lining shall be not less than 14
inch.

2'. Baffles shall not interfere with the free drainage of the tank.
The area of one baffle plate shall not exceed 40 percent of the cross-
sectional area of the tank, and the entire baffle shall be on one side
of the longitudinal centerline of the tank. If installed, consecutive
baffles shall be on opposite sides of the tank and not less than 48 inches
apart and so designed that walk through accessibility shall be pro-
vided to all areas for inspection and cleaning purposes.

15

j. Pump and/or hose cabinets on farm pickup tanks shall be con-
structed as follows:

(1) Inside corners of pumps or hose cabinets on transportation
tanks shall have a minimum radii of 1/8 inch.

(2) The inside lining of cabinets, doors, and other fixed at-
tachments shall be smooth and made of stainless steel or other
equally corrosion resistant material.

(3) Sample trays and sample compartments for butterfat sam-
ples shall be made of stainless steel or other equally corrosion
resistant material.

(4) A roof overhang or suitable dry molding shall be provided
over cabinet doors.

(5) Pump assemblies having a base area of 1 square foot or
less shall have a minimum clearance of 2 inches between the pump
base and cabinet floor, and 3 inches between pump and cabinet
walls. Pumps having larger bases shall have a minimum of 3
inches of clearance between the pump, cabinet walls, and floor.
When mounted on the floor of the cabinet using a solid base, a
nonabsorbent sealing gasket shall be used. The base should be
removed and the gasket replaced at regular intervals.

76. Single lengths of transfer tubing shall not exceed 8 feet except
where suitable cleaning facilities are provided and the inside diameter
shall be not less than 1% inches. If two lengths of flexible tubing are
used, they Shall be connected either by the use of sanitary couplings
or a piece of sanitary tubing with clamps which can be removed With-
out the use of tools. Sanitary caps shall be furnished for each end
of the tubing and the pump.

5. Evaporatorsr and Vacuum Pans

a. The minimum inside diameter of product heat exchanged tubing
shall be that of nominal 1 inch o.d., 16 US. standard gauge tubing.

b. The minimum space between coils shall be 21/2 inches, the mini-
mum space between coils and vacuum pan walls shall be 3 inches, and
the minimum space between coil banks shall be 31/; inches.

0. Openings for vacuum breaker and sampling valve shall be in
the product contact surface.

d. An automatic condenser water level control preventing water
from entering the product shall be provided by one of the following
means:

(1) A barometric leg (fig. 12).

(2) A surface condenser in which the vapor and condensing
water are separated by metal walls and do not come in contact
with each other.

(3) A safety shut-off valve, located in the water feed line to
the condenser, automatically activated by a control which will

16

BAROMETRIC LEG
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FIGURE 12

shut off the flow of water when the water level rises above a
predetermined point in the condenser (fig. 13). This valve may
be activated by water, air, or electricity, and shall be so designed
that failure of the primary motivating power will automatically
stop the flow of water.

6. Equipment for Supplying Air Under Pressure in Contact With Milk.
Milk Products, and Product Contact Surfaces

a. Filter Material.

(1) Intake and Air Pipeline F27ferx.—Shall consist of fiberglass,
cotton flannel, wool flannel, spun metal, electrostatic material or other
equally acceptable filtering media, which are nonshedding and which
do not release to the air toxic volatiles, or volatiles which may impart
any flavor or odor to the product.

( 2) Disposable Media F Mensa—Shall consist of cotton flannel, wool
flannel, spun metal, nonwoven fabric, U.S.P. absorbent cotton fiber,
or suitable inorganic material which, under conditions of use, are
nontoxic and. nonshedding. Chemical bonding material contained in

17

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COOLING WATER IN

 

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FIGURE 13

the media shall be nontoxic, nonvolatile, and insoluble under all con-
ditions of use. Disposable media shall not be reused.

Z). Filter Performance

(1) Intake Filters.—The efficiency of intake filters shall be at least
50 percent as measured by the National Bureau of Standards “Dust
Spot Method,” using atmospheric dust as the test aerosol.

(2) Air Pipeline and Disposable F Liters—The efliciency of either
air pipeline filters or disposable filters shall be at least 50 percent as
measured by the DOP test. (Filter Units, Protective Clothing, Gas
Mask Components, and Related Products: Performance Test Method,
Military Standard No. 282, Section 102.9.1; Naval Supply Depot,
5801 Tabor Avenue, Philadelphia, Pa).

0. Piping
Air distribution piping, fittings, and gaskets between the down-
stream terminal filter and any product or product contact surface

shall be sanitary milk piping, except where the compressing equipment
is of the fan or blower type. Provided, that when air is used for such

operations as removing containers from mandrels, other nontoxic
materials may be used.

(1. Fabrication and Installation

(1) Air Supply E quipment—The compressing equipment shall be
of such design so as to preclude contamination of the air with lubricant.
vapors and fumes. The air supply shall be taken from a clean space
or from relatively clean outer air, and shall pass through a filter up-
stream from the compressing equipment. This filter shall be so lo-
cated and constructed that it is easily accessible for examination, and
the filter media are easily removable for cleaning or replacing. The
filter shall be protected from weather, drainage, water, product spill-
age, and physical damage.

(2) Moisture Removal E quipment.—If necessary to cool the com-
pressed air, a liquid-cooled aftercooler shall be installed between the
compressor and the air storage tank for the purpose of removing
moisture from the compressed air. (See fig. 14.)

e. Filters and Moisture Traps

(1) Filters shall be constructed so as to assure effective passage of
air through the filter media only.

( 2) The air under pressure shall pass through an oil-free filter and
moisture trap for removal of solids and liquids. The filter and trap
shall be located in the air pipeline downstream from the compressing
equipment, and from the air tank, if one is used. (See fig. 14.) Air
pipeline filters and moisture traps downstream from compressing
equipment shall not be required when the compressing equipment is
of the fan or blower type. (See figs. 15 and 16.)

(3) A disposable media filter shall be located in the sanitary air
pipelines upstream from and as close as possible to each point of
application or ultimate use of the air.

f. Air Piping

Except where the compressing equipment is of the fan or blower
type, the following requirements shall be met:

(1) The air piping from the compressing equipment to the
filter and moisture trap shall be readily drainable.

(2) A product check valve of sanitary design shall be installed
in the air piping downstream from the disposable media filter to
prevent backflow of product into the air pipeline; except that a
check valve shall not be required if the air piping enters the
product zone from a point higher than the product overflow level
which is open to the atmosphere.

7. Product Pumps and Meters
a. Pump and meter impellers 0r rotors, and cases or stators which
operate in conjunction with a metallic counterpart, may be made of or

19

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FIGURE 15

covered With rubber or rubberlike materials. Rubber or rubberlike
materials shall be of such composition as to retain their surface and
conformation characteristics under conditions encountered in normal
use and cleaning operations.

I). The parts forming the space between the motor and the pump
body shall be constructed in such a way that they are easily accessible
for cleaning, and drain freely.

c. On pumps with legs designed to be fixed to the floor, the minimum
clearance between the lowest part of the base and the floor shall be 4
inches.

d. Readily portable pumps not permanently attached may have leg
heights of 2 inches. Readily portable pumps are defined as those
having a base area not more than 1 square foot.

6. Pumps, which because of size and type cannot be mounted on legs,
shall be mounted on a base designed for grouting and sealing.

f. Shaft seal shall be of the sanitary type, easily removable for in—
spection and cleaning.

8. Batch and Continuous Ice Cream Freezers

a. Bearings, springs, shafts, couplings, drive and mounting pins,
and scraping parts may be made of nontoxic hardenable, corrosion
resistant stainless metal (400 series stainless steel, aluminum bronze
alloy, or equivalent), or these materials covered with an engineering
plating of nickel, chromium, or an equally corrosion resistant, non-
toxic metal.

5. Freezing cylinders may also be made of steel or other structurally
suitable heat-exchange metal made corrosion resistant and wear resist-
ant by covering with an engineering plating of chromium or an equally
corrosion and wear-resistant nontoxic metal. The plating shall be
not less than 0.002 inch thick.

0. When air under pressure is used, a single service filter shall be
installed in the air line as close as practicable to the point of air appli-

21

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cation, and a product check valve of sanitary design shall be installed
downstream from such filter. The filter shall be capable of removing
particles of 5 microns (0.0002 inch) or larger in size.

(1. Integral mix supply tanks of such capacity that their contents
are not normally transferred to the freezing chamber within one-half
hour shall be so designed that the mix can be held at all times below
45° F.

U.S. GOVERNMENT PRINTING OFFICE: 1984 0—738-647

22

 

 

 

 

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