296-307-400 Anhydrous ammonia.
296-307-40001 What does this section cover?
296-307-40003 What definitions apply to this section?
296-307-40005 What general requirements apply to the storage and handling
of anhydrous ammonia?
296-307-40007 What requirements apply to systems mounted on farm wagons
(implements of husbandry) for the transportation of ammonia? 296-307-40009 What requirements apply
to systems mounted on farm wagons (implements of husbandry) for the application
of ammonia?
296-307-40011 What requirements must approved anhydrous ammonia equipment
meet?
296-307-40013 What requirements apply to the construction, original
test, and requalification of nonrefrigerated containers? 296-307-40015 How must nonrefrigerated
containers and systems (other than DOT containers be marked?
296-307-40017 Where may anhydrous ammonia containers be located?
296-307-40019 What requirements apply to container accessories?
296-307-40021 What requirements apply to piping, tubing, and fittings?
296-307-40023 What specifications must hoses meet?
296-307-40025 What requirements apply to safety-relief devices?
296-307-40027 What emergency precautions are required when handling
anhydrous ammonia?
296-307-40029 What requirements apply to filling densities?
296-307-40031 What requirements apply to the transfer of liquids?
296-307-40033 What requirements apply to tank car unloading points
and operations?
296-307-40035 What requirements apply to the liquid-level gauging
device?
296-307-40037 How should aboveground uninsulated containers be maintained?
296-307-40039 What requirements apply to electrical equipment and
wiring?
“Certified” means the equipment has been tested by a nationally
recognized testing laboratory and meets nationally recognized standards
or is safe for a specific use; or is a kind whose production is periodically
inspected by a nationally recognized testing laboratory, and bears identification
of certification.
“DOT” means the Federal Department of Transportation.
“DOT container” means a container constructed according to the
requirements of 49 CFR chapter 1.
“DOT cylinder” means a cylinder that meets the requirements of
49 CFR chapter I.
“Labeled” means the equipment has an attached label, symbol, or
other identifying mark of a nationally recognized testing laboratory that
makes periodic inspections of the production of such equipment, and the
label indicates compliance with nationally recognized standards or tests.
WAC 296-307-40005
What general requirements apply to the storage and handling of anhydrous
ammonia?
(1) All employees must use at least gloves and goggles and may supplement
with a face shield while working on or with charged anhydrous ammonia
equipment.
(2) You must ensure that equipment is inspected before each day's work.
Conditions that would contribute to leaks shall be corrected.
(3) Hose end-valves must be closed when not in use to prevent accidental
discharge in case the main valve is opened.
(4) Relief and vapor valves must discharge away from the operator's working
position.
WAC 296-307-40007
What requirements apply to systems mounted on farm wagons (implements
of husbandry) for the transportation of ammonia?
All anhydrous ammonia containers with a capacity of 3,000 gallons or
less and equipment mounted on farm wagons (implements of husbandry) that
is used to transport ammonia must meet the requirements of this section.
(1) Containers must meet the following mounting requirements:
(a) The farm wagon or container has a stop so the container does not
dislodge from its mounting when a farm wagon stops suddenly.
(b) The container is anchored to the farm wagon at one or more places
on each side of the container.
(c) The weight of containers mounted on four-wheel farm wagons, is
distributed evenly over both axles.
(d) When the cradle and the container are not welded together, material
between them eliminates metal-to-metal friction.
(2) Container accessories must meet the following requirements:
(a) Each container has a fixed maximum liquid-level gauge.
(b) All containers with more than 250-gallon capacity have a pressure
gauge with a dial graduated from 0-400 psi.
(c) The filling connection is fitted with one of the following:
(i) A combination back-pressure check valve and excess-flow valve;
or
(ii) One double or two single back-pressure check valves; or
(iii) A positive shut-off valve that has either an internal back-pressure
check valve or an internal excess flow valve.
(d) All containers with more than 250-gallon capacity are equipped
for spray loading or with an approved vapor return valve.
(e) All vapor and liquid connections have approved excess flow valves
or quick-closing internal valves that are only open for operating.
Exception: Safety-relief valves and connections
that are specifically exempted by WAC
296-307-40019(5) are exempt from this requirement.
(f) Fittings are protected from physical damage by a rigid guard. The
guard is designed to withstand force from any direction, equal to twice
the weight of the container and lading, at a safety factor of four.
If the guard is fully enclosed, the safety-relief valves are properly
vented through the guard.
(g) If a liquid withdrawal line is installed in the bottom of a container,
the connections and hose are at least as high as the lowest horizontal
edge of the farm wagon axle.
(h) Both ends of the hose are secure while in transit.
(3) Each side and the rear end of the container must be marked in letters
at least four inches high, with the words “anhydrous ammonia” or, “caution-ammonia,”
or marked according to DOT regulations.
(4) Farm wagons (implements of husbandry) must meet all state regulations
and the following requirements:
(a) All farm wagons must be securely attached to the vehicle drawing
them by drawbars with safety chains.
(b) A farm wagon must be constructed so that it will follow the path
of the towing vehicle and will prevent the towed wagon from whipping
or swerving dangerously from side to side.
(c) All farm wagons must have five gallons or more of readily available
clean water.
(2) Container valves and accessories must meet the following requirements:
(a) Each container has a fixed maximum liquid-level gauge.
(b) The filling connection is fitted with one of the following:
(i) A combination back-pressure check valve and excess-flow valve;
or
(ii) One double or two single back-pressure check valves; or
(iii) A positive shut-off valve that has either an internal back-pressure
check valve or an internal excess flow valve.
(c) An excess-flow valve is not required in the vapor connection if
the controlling orifice is a maximum of 7/16 inch in diameter and the
valve is a hand-operated shut-off valve. To assist in filling applicator
tanks, you may bleed vapors to the open air, if this requirement is
met.
(d) Metering devices may be connected directly to the tank withdrawal
valve. You may use a union type connection between the tank valve and
metering device. You may use remote mounting of metering devices if
the hose meets the requirements of Appendix B. When the applicator tank
is trailed and the metering device is remotely mounted, such as on the
tractor tool bar, you must use an automatic break-away type, self-closing
coupling.
(e) No excess-flow valve is required in the liquid withdrawal line
if the controlling orifice between the contents of the container and
the outlet of the shut-off valve is a maximum of 7/16 inch in diameter.
WAC 296-307-40011
What requirements must approved anhydrous ammonia equipment meet?
All equipment must be approved by one of the following methods:
(1) The equipment was installed before February 8, 1973, and was approved
and tested, and installed according to either the requirements of the
American National Standard for the Storage and Handling of Anhydrous Ammonia,
K61.1, or the Fertilizer Institute Standards for the Storage and Handling
of Agricultural Anhydrous Ammonia, M-1, in effect at the time of installation;
or
(2) The equipment is accepted, or certified, or listed, or labeled, or
otherwise determined to be safe by a nationally recognized testing laboratory;
or
(3) (a) The equipment is a type that no nationally recognized testing
laboratory accepts, certifies, lists, labels, or determines to be safe;
and
(b) The equipment is inspected or tested by an authority responsible
for enforcing occupational safety provisions of a law, code, or regulation
pertaining to the storage, handling, transport, and use of anhydrous
ammonia; and
(c) The equipment is found in compliance with either the requirements
of the American National Standard for the Storage and Handling of Anhydrous
Ammonia, K61.1, or the Fertilizer Institute Standards for the Storage
and Handling of Agricultural Anhydrous Ammonia, M-1, in effect at the
time of installation; or
(4) For a custom-designed and custom-built unit:
(a) You cannot find a nationally recognized testing laboratory or authority
responsible for the enforcement of a law, code or regulation pertaining
to the storage, transportation and use of anhydrous ammonia that is
willing to accept, certify, list, label or determine to be safe your
custom equipment; and
(b) You have on file a document attesting to its safe condition following
appropriate tests. The document must be signed by a registered professional
engineer or qualified person. The document must describe the test bases,
test data and results, and also the qualifications of the certifying
person.
WAC 296-307-40013
What requirements apply to the construction, original test, and requalification
of nonrefrigerated containers?
The code is the Unfired Pressure Vessel Code of the American Society
of Mechanical Engineers (Section VIII of the ASME Boiler Construction
Code), 1952, 1956, 1959, 1962, 1965, 1968 and 1971 editions, the joint
code of the American Petroleum Institute and the American Society of Mechanical
Engineers (API-ASME Code) 1951 edition, and amendments or later editions,
as adopted.
(1) Containers used with systems covered in WAC
296-307-40005 and 296-307-40007
must be constructed and tested according to the code.
Exception:
Construction under Table UW-12 at a basic joint
efficiency of under 80% is prohibited. Containers built according to code
are exempt from paragraphs UG-125 to UG-128, inclusive, and paragraphs
UG-132 and UG-133 of the code.
Note:
This subsection allows the continued use or reinstallation
of containers constructed and maintained according to the 1949, 1950,
1952, 1956, 1959, 1962, 1965 and 1968 editions of the Unfired Pressure
Vessel Code of the ASME or any revisions thereof in effect at the time
of fabrication.
(2) Containers more than 36 inches in diameter or 250 gallons water capacity
must be constructed to meet one or more of the following requirements:
(a) Containers must be stress relieved after fabrication according
to the code; or
(b) Cold-formed heads, when used, must be stress relieved; or
(c) Hot-formed heads must be used.
(3) Welding to the shell, head, or any other part of the container subject
to internal pressure must be according to the code. Other welding is permitted
only on saddle plates, lugs, or brackets attached to the container by
the container manufacturer.
Containers used with systems covered in subsection (4) of this section
must be constructed and tested in accordance with the DOT specifications.
(4) Containers must comply with the department of transportation specifications
and must be maintained, filed, packaged, marked, labeled and shipped to
comply with current DOT regulations and American National Standard method
of marking Portable Compressed Gas Containers to Identify the Material
Contained, Z48.1-1954 R1970. See Appendix C for availability
(a) With indication that the container or system meets the
requirements of the code under which the container is constructed.
(b) With indication on the container and system nameplate when
the system is designed for underground installation.
(c) With the name and address of the supplier of the container
or the trade name of the container and with the date of fabrication.
(d) With the water capacity of the container in pounds at 60°F
or gallons, United States standard.
(e) With the design pressure in pounds per square inch gauge.
(f) With the wall thickness of the shell and heads.
(g) With indication of the maximum fill level for liquid anhydrous
ammonia between 20°F and 100°F. Markings must be in increments
of not more than 20°F.
Exception: Containers with fixed maximum
level indicators, such as fixed length dip tubes, or containers
that are filled by weight are exempt from this requirement.
(h) With the outside surface area in square feet.
(i) With minimum temperature in Fahrenheit for which the container
is designed.
(j) The marking must be on the container itself or on a permanently
attached nameplate.
(3) All main operating valves on permanently installed containers with
a capacity of over 3,000 water gallons must be identified to show whether
the valve is in liquid or vapor service. The valve must be identified
as follows:
(a) The word liquid (or liquid valve), vapor (or vapor valve), as appropriate,
must be placed on or within twelve inches of the valve by means of a
stencil tag or decal.
(b) Liquid valves must be painted orange and vapor valves must be painted
yellow. The legend orange-liquid, yellow-vapor must be displayed in
one or more conspicuous places at each permanent storage location. The
legend must have letters at least two inches high and must be placed
against a contrasting background.
(4) "Marking refrigerated containers." Each refrigerated container
must be marked with a name plate on the outer covering in an accessible
place as specified in the following:
With the notation, "Anhydrous Ammonia"
With the name and address of the builder and the date of fabrication
With the water capacity of the container in gallons, U.S. Standard
With the design pressure
With the minimum temperature in degrees Fahrenheit for which the container
was designed
The maximum allowable water level to which the container may be filled
for test purposes
With the density of the product in pounds per cubic foot for which
the container was designed
With the maximum level to which the container may be filled with liquid
anhydrous ammonia.
WAC 296-307-40017
Where may anhydrous ammonia containers be located?
(1) When selecting the location for a storage container, you must take
into account the physiological effects of ammonia and adjacent fire hazards.
Containers located indoors must be in areas especially approved for container
storage.
(2) Containers must be located at least fifty feet from a dug well or
other sources of potable water supply, unless the container is a part
of a water treatment installation.
(3) Permanent storage containers must be located outside densely populated
areas.
(4) Containers must be located according to the following:
Minimum
distances (feet) from container to:
Nominal
capacity of container
Line of
adjoining property that may be built upon, highways and main line
of railroad
Place of
public assembly
Institution
occupancy
Over 500 to
2,000
25
150
250
Over 2,000
to 30,000
50
300
500
Over 30,000
to 100,000
50
450
750
Over 100,000
50
600
1,000
(5) Storage areas must be kept free of readily ignitable materials such
as waste, weeds and long dry grass.
(1) All accessories must be designed for at least the maximum working
pressure of the part of the system on which they are installed. All accessories
must be fabricated from materials suitable for anhydrous ammonia service.
(2) All connections to containers must have shut-off valves located as
close to the container as practical.
Exception: Safety-relief devices, gauging devices,
or those fitted with a No. 54 drill size orifice are exempt from this
requirement.
(3) All required excess flow valves must close automatically at the rated
flows of vapor or liquid specified by the manufacturer. The connections,
lines, valves, and fittings must have a greater capacity than the rated
flow of the excess flow valve.
(4) Liquid-level gauging devices that require bleeding to the atmosphere
and that are constructed so that outward flow is a maximum of that passed
by a No. 54 drill size opening may be installed without excess flow valves.
(5) Openings from the container or through fittings attached directly
on container to which pressure gauge connections are made may be installed
without excess flow valves if the openings are a maximum of No. 54 drill
size.
(6) Required excess flow and back pressure check valves must be located
inside the container or outside as close as practical to where the line
enters the container. When located outside, the installation must be made
to prevent any stress beyond the excess flow or back pressure check valve
from causing a break between the container and the valve.
(7) Excess flow valves must be designed with a bypass that is a maximum
of No. 60 drill size opening to allow equalization of pressures.
(8) Shut-off valves provided with an excess flow valve must be designed
for proper installation in a container connection so that the excess flow
valve will close if the shut-off valve breaks.
(9) All excess flow valves must be plainly and permanently marked with
the name or trademark of the manufacturer, the catalog number, and the
rated capacity.
WAC 296-307-40021
What requirements apply to piping, tubing, and fittings?
(1) All piping, tubing and fittings must be made of material suitable
for anhydrous ammonia service.
(2) All piping, tubing and fittings must be designed for a pressure of
at least the maximum pressure to which they may be subjected in service.
(3) All piping must be well supported and allow for expansion and contraction.
All refrigeration system piping must conform to the Refrigeration Piping
Code (ANSI B31.5 1966 addenda B31.1a-1968), a section of the American
Standard Code for Pressure Piping, as it applies to ammonia.
(4) Piping used on nonrefrigerated systems must meet the requirements
of ASTM A-53-1969 Grade B Electric Resistance Welded and Electric Flash
Welded Pipe. Pipe must be at least Schedule 40 when joints are welded,
or welded and flanged. Pipe must be at least Schedule 80 when joints are
threaded. Brass, copper, or galvanized steel pipe or tubing is prohibited.
(5) All metal flexible connections for permanent installations must have
a minimum working pressure of 250 psig (safety factor of 4). For
temporary installations, you may use hose that meets the requirements
of WAC
296-307-40023.
(6) Cast iron fittings are prohibited. You must use fittings made especially
for ammonia service of malleable or nodular iron that meet the requirements
of Specification ASTM A47 or ASTM A395.
(7) All piping, tubing, and fittings must allow for expansion, contraction,
jarring, vibration, and settling.
(8) You must make adequate provision to protect all exposed piping from
physical damage from moving machinery, the presence of automobiles or
trucks, or other strain on the piping.
(9) Joint compounds must be resistant to ammonia.
(10) After assembly, all piping and tubing must be tested and proved
to be free from leaks at pressure that is at least equal to the normal
operating pressure of the system.
(1) Hose used in ammonia service and subject to container pressure must
meet the requirements of the joint Rubber Manufacturers Association and
the Fertilizer Institute “Hose Specifications for Anhydrous Ammonia.”
(2) Hose subject to container pressure must be designed for a minimum
working pressure of 350 psig and a minimum burst pressure of 1750 psig.
Hose assemblies must be able to withstand a test pressure of 500 psig.
(3) Hose and hose connections on the low pressure side of flow control
or pressure reducing valves on devices discharging to atmospheric pressure
must be designed for the maximum low side working pressure. All connections
must be designed, constructed, and installed to prevent leaks when connected.
(4) Where liquid transfer hose is not drained after transfer operations,
the hose must have an approved shut-off valve at the discharge
end. You must provide a method to prevent excessive hydrostatic
pressure in the hose. (See WAC
296-307-40025.)
(5) On all hose 1/2-inch outside diameter and larger, used for the transfer
of anhydrous ammonia liquid or vapor, you must ensure that the following
information is etched, cast, or impressed at five-foot intervals:
(1) Every container used in systems covered by WAC
296-307-400 must have one or more spring-loaded safety-relief
valves or the equivalent.
(2) The discharge from safety-relief valves must be vented away from
the container, upward, and unobstructed to the atmosphere. All safety-relief
valve discharge openings must have suitable raincaps that allow free discharge
of the vapor and prevent water from entering. You must provide a method
to drain condensate. The rate of discharge must be as follows:
Surface
area Flow rate sq. ft. CFM air
Surface
area Flow rate sq. ft. CFM air
Surface
area Flow rate sq. ft. CFM air
20
258
185
1,600
900
5,850
25
310
190
1,640
950
6,120
30
360
195
1,670
1,000
6,380
35
408
200
1,710
1,050
6,640
40
455
210
1,780
1,100
6,900
45
501
220
1,850
1,150
7,160
50
547
230
1,920
1,200
7,410
55
591
240
1,980
1,250
7,660
60
635
250
2,050
1,300
7,910
65
678
260
2,120
1,350
8,160
70
720
270
2,180
1,400
8,410
75
762
280
2,250
1,450
8,650
80
804
290
2,320
1,500
8,900
85
845
300
2,380
1,550
9,140
90
885
310
2,450
1,600
9,380
95
925
320
2,510
1,650
9,620
100
965
330
2,570
1,700
9,860
105
1,010
340
2,640
1,750
10,090
110
1,050
350
2,700
1,800
10,330
115
1,090
360
2,760
1,850
10,560
120
1,120
370
2,830
1,900
10,800
125
1,160
380
2,890
1,950
11,030
130
1,200
390
2,950
2,000
11,260
135
1,240
400
3,010
2,050
11,490
140
1,280
450
3,320
2,100
11,720
145
1,310
500
3,620
2,150
11,950
150
1,350
550
3,910
2,200
12,180
155
1,390
600
4,200
2,250
12,400
160
1,420
650
4,480
2,300
12,630
165
1,460
700
4,760
2,350
12,850
170
1,500
750
5,040
2,400
13,080
175
1,530
800
5,300
2,450
13,300
180
1,570
850
5,590
2,500
13,520
Surface area = total outside surface area of container in square feet.
When the surface area is not stamped on the name plate or when the marking
is not legible, calculate the area with one of the following formulas:
Hemispherical heads: Area = (Length in feet) X (outside diameter
in feet) X 3.1416.
Other than hemispherical heads: Area = (Length in feet) + (0.3 outside
diameter in feet) X (outside diameter in feet) X 3.1416.
Spherical container: Area = (outside diameter in feet)2 X 3.1416.
Flow rate: CFM air = cubic feet per minute of air required at standard
conditions, 60F and atmospheric pressure (14.7 psia).
For containers with total outside surface area greater than 2,500 sq.
ft., the formula is: Flow rate CFM air = 22.11 A0.82 where A = outside
surface area of the container in square feet.
(3) Container safety-relief valves must be set for start to discharge
as follows, according to the design pressure of the container.
Containers
Minimum
Maximum
*
ASME U-68,
U-69
110%
125%
ASME U-200,
U-201
95%
100%
ASME 1952,
1956, 1959, 1962, 1965, 1968 or 1971
95%
100%
API-ASME
95%
100%
U.S. Coast
Guard
As required
by USCG regulations
DOT
As required
by DOT regulations
*Note: Plus
a relief valve manufacturer's tolerance of ten percent.
(4) Safety-relief devices used in systems covered by WAC 296-307-400
must be constructed to discharge at a rate equal to or greater than the
rates required in subsection (2) of this section before the pressure exceeds
120% (not including the tolerance referred to in subsection (3) of this
section) of the maximum permitted start-to-discharge pressure setting
of the device.
(5) Safety-relief valves must be arranged to minimize tampering. If the
pressure setting adjustment is external, the relief valves must have a
sealable adjustment.
(6) Shut-off valves installed between the safety-relief valves and the
containers or systems described in WAC
296-307-400 are prohibited.
Exception: A shut-off valve may be used where the
arrangement of the valve allows the required capacity flow through the
relief valves.
Exception example 1: A three-way valve installed
under two safety-relief valves, each of which has the required rate of
discharge and is installed to allow either of the safety-relief valves
to be closed off, but does not allow both safety valves to be closed off
at the same time.
Exception example 2: Two separate relief valves
are installed with individual shut-off valves. The two shut-off valve
stems must be mechanically interconnected to allow the full required flow
of one safety-relief valve at all times.
Exception example 3: A safety-relief valve manifold
that allows one valve of two, three, four or more to be closed off and
the remaining valve or valves will provide not less than the rate of discharge
shown on the manifold nameplate.
(7) Safety-relief valves must have direct communication with the vapor
space of the container.
(8) Each safety-relief valve used with systems described in WAC
296-307-400 must be plainly and permanently marked as follows:
(a) With the letters “AA” or the symbol NH3.
(b) The pressure in pounds per square inch gauge (psig) at which the
valve is set to start to discharge.
(c) The rate of discharge of the valve in cubic feet per minute of
air at 60°F and atmospheric pressure (14.7 psia).
(d) The manufacturer's name and catalog number.
For example: A safety-relief valve marked AA-250-4200
(air) mean the valve is suitable for use on an anhydrous ammonia container;
that it is set to start to discharge at 250 psig; and that its rate
of discharge is 4,200 cubic feet per minute of air.
(9) No connection to the safety-relief valve may restrict the flow capacity
on either the upstream or downstream side.
(10) The manufacturer or supplier of a safety-relief valve manifold must
publish complete data showing the flow rating through the combined assembly
of the manifold with safety-relief valves installed. The manifold flow
rating must be determined by testing the manifold with all but one valve
discharging. The flow rate must be determined by the restricted opening
or openings or those having the lowest flow. The valve must be marked
as required in subsection (7) of this section.
(11) A hydrostatic relief valve must be installed between each pair of
valves in the liquid ammonia piping or hose where liquid may be trapped
to release into the atmosphere at a safe location.
(12) Discharge from safety-relief devices must not terminate in or beneath
any building.
WAC 296-307-40027
What emergency precautions are required when handling anhydrous ammonia?
(1) You must train employees required to handle ammonia in the safe operating
practices and the proper action to take in an emergency. Employees must
be instructed to use the equipment listed in subsection (3) of this section
in an emergency.
(2) If ammonia system leaks, the employees trained for and designated
to act in emergencies must:
(a) See that anyone not required to deal with an emergency is evacuated
from the contaminated area.
(b) Have two suitable gas masks in readily accessible locations. Full
face masks with ammonia canisters as certified by NIOSH under 42 CFR
Part 84, are suitable for emergency action for most leaks, particularly
those that occur outdoors. For protection in concentrated ammonia atmospheres,
self-contained breathing apparatus is required.
(c) Wear gauntlet type plastic or rubber gloves and wear plastic or
rubber suits in heavily contaminated atmospheres.
(d) Shut off the appropriate valves.
(3) All storage systems must have on hand at least the following equipment
for emergency and rescue purposes:
(a) *One full face gas mask with anhydrous ammonia refill canisters.
(b) **One pair of protective gloves.
(c) **One pair of protective boots.
(d) **One protective slicker and/or protective pants and jacket.
(e) Easily accessible shower and/or at least 50 gallons of clean water
in an open top container.
(f) Tight-fitting vented goggles or one full face shield.
* If ammonia vapors are detected when the mask is applied, the leave
the area immediately. The life of a canister in service is controlled
by the percentage of vapors to which it is exposed. Canisters must not
be opened until ready for use and should be discarded after use or as
recommended by the canister manufacturer. Unopened canisters may be
guaranteed for as long as three years and all should be dated when received.
In addition, an independently supplied air mask of the type used by
fire departments may be used for emergencies.
**Gloves, boots, slickers, jackets, and pants must be made of rubber
or other material impervious to ammonia.
(4) Where several persons are usually present, additional safety equipment
may be necessary.
(5) Each tank motor vehicle transporting anhydrous ammonia, except farm
applicator vehicles, must carry a container of at least five gallons of
water and must have a full face gas mask, a pair of tight-fitting goggles
or one full face shield. The driver must be instructed in their use and
the proper action to take to provide for the driver's safety.
(6) If a leak occurs in transportation equipment and it is impractical
to stop the leak, the driver should move the vehicle to an isolated location.
(7) If liquid ammonia contacts the skin or eyes, the affected area should
be promptly and thoroughly flushed with water. Do not use neutralizing
solutions or ointments on affected areas. A physician must treat all cases
of eye exposure to liquid ammonia.
Filling density means the percent ratio of the weight of the gas in
a container to the weight of water at 60°F that the container will hold.
One pound of water equals 27.737 cubic inches at 60°F. To determine the
weight capacity of the tank in pounds, the weight of a gallon (231 cubic
inches) of water at 60°F in air must be 8.32828 pounds.
(1) The filling densities for nonrefrigerated containers must not exceed
the following:
Aboveground
Underground
(i) Uninsulated
56%
58%
(ii) Insulated
57%
(iii) DOT
containers shall be filled according to DOT regulations.
This corresponds
to 82% by volume at -28°F, 85% by volume at 5°F, 87.5 % by volume
at 30°F, and 90.6% by volume at 60°F.
(2) When containers are filled according to liquid level by any gauging
method other than a fixed length dip tube gauge, each container should
have a thermometer well so that the internal liquid temperature can be
easily determined and the amount of liquid and vapor in the container
corrected to a 60°F basis.
WAC 296-307-40031
What requirements apply to the transfer of liquids?
(1) Anhydrous ammonia must always be at a temperature suitable for the
material of construction and design of the receiving containers. Ordinary
steels are not suitable for refrigerated ammonia. See Appendix R of API
Standard 620 “Recommended Rules for Design and Construction of Large Welded
Low-Pressure Storage Tanks” for materials for low temperature service.
(2) At least one attendant must supervise the transfer of liquids from
the time the connections are first made until they are finally disconnected.
(3) Flammable gases or gases that will react with ammonia (such as air)
must not be used to unload tank cars or transport trucks.
(4) Containers must be charged or used only on authorization of the owner.
(5) Containers must be gauged and charged only in the open atmosphere
or in buildings approved for that purpose.
(6) Pumps used for transferring ammonia must be recommended and labeled
for ammonia service by the manufacturer.
(a) Pumps must be designed for at least 250 psig working pressure.
(b) Positive displacement pumps must have installed, off the discharge
port, a constant differential relief valve discharging into the suction
port of the pump through a line large enough to carry the full capacity
of the pump at relief valve setting. The setting and installation must
be according to the pump manufacturer's recommendations.
(c) On the discharge side of the pump, before the relief valve line,
there must be a pressure gauge graduated from 0 to 400 psig installed.
(d) Plant piping must contain shut-off valves located as close as practical
to pump connections.
(7) Compressors used for transferring or refrigerating ammonia must be
recommended and labeled for ammonia service by the manufacturer.
(a) Compressors, except those used for refrigeration, must be designed
for at least 250 psig working pressure. Crank cases of compressors not
designed to withstand system pressure must be protected with a suitable
safety-relief valve.
(b) Plant piping must have shut-off valves located as close as practical
to compressor connections.
(c) A safety-relief valve large enough to discharge the full capacity
of the compressor must be connected to the discharge before any shut-off
valve.
(d) Compressors must have pressure gauges at suction and discharge
graduated to at least one and one-half times the maximum pressure that
can develop.
(e) Adequate means, such as drainable liquid trap, must be provided
on the compressor suction to minimize the entry of liquid into the compressor.
(f) Where necessary to prevent contamination, an oil separator must
be provided on the discharge side of the compressor.
(8) Loading and unloading systems must be protected by suitable devices
to prevent emptying of the storage container or the container being loaded
or unloaded if the hose is cut. Backflow check valves or properly sized
excess flow valves must be installed where necessary to provide this protection.
In the event that valves are not practical, remotely operated shut-off
valves may be installed.
(9) Meters used to measure liquid anhydrous ammonia must be recommended
and labeled for ammonia service by the manufacturer.
(a) Liquid meters must be designed for a minimum working pressure of
250 psig.
(b) The metering system must incorporate devices that will prevent
the inadvertent measurement of vapor.
WAC 296-307-40033
What requirements apply to tank car unloading points and operations?
(1) Provisions for unloading tank cars must meet DOT requirements.
(2) Unloading operations must be performed by reliable employees who
are properly instructed and responsible for careful compliance with all
procedures.
(3) Caution signs must be placed on the track or car to give necessary
warning to anyone approaching car from the open end of the siding. The
signs must be left up until after car is unloaded and disconnected from
discharge connections. Signs must be of metal or other suitable material,
at least 12 by 15 inches, and bear the words “STOP-Tank car connected”
or “STOP-Men at work.” The word “STOP” must be in letters at least four
inches high and the other words in letters at least two inches high. The
letters must be white on a blue background.
(4) The track of a tank car siding must be substantially level.
(5) Brakes must be set and wheels blocked on all cars being unloaded.
(6) Tank cars of anhydrous ammonia must be unloaded only at approved
locations meeting the requirements of WAC
296-307-40025(4) and 296-307-40031(8).
WAC 296-307-40035
What requirements apply to the liquid-level gauging device?
(1) Each container except those filled by weight must have an approved
liquid-level gauging device.
(2) All gauging devices must be arranged so that the maximum liquid level
to which the container is filled is easily determined.
(3) Gauging devices that require bleeding of the product to the atmosphere
such as the rotary tube, fixed tube, and slip tube devices, must be designed
so that the maximum opening of the bleed valve is a maximum of No. 54
drill size unless provided with an excess flow valve.
(4) Gauging devices must have a design pressure equal to or greater than
the design pressure of the container on which they are installed.
(5) Fixed liquid-level gauges must be designed so that the maximum volume
of the container filled by liquid is a maximum of 85% of its water capacity.
The coupling into which the fixed liquid-level gauge is threaded must
be placed at the 85% level of the container. If located elsewhere, the
dip tube of this gauge must be installed so that it cannot be readily
removed.
Note: This does not apply to refrigerated storage.
(6) Columnar gauge glasses must be restricted to stationary storage installation.
They must have shut-off valves having metallic hand wheels, excess flow
valves, and extra heavy glass adequately protected by a metal housing
applied by the gauge manufacturer. They must be shielded against the direct
rays of the sun.
WAC 296-307-40037
How should aboveground uninsulated containers be maintained?
Aboveground uninsulated containers should have a reflective surface
maintained in good condition. We recommend white for painted surfaces,
but other light reflecting colors are acceptable.
WAC 296-307-40039
What requirements apply to electrical equipment and wiring?
(1) Electrical equipment and wiring for use in ammonia installations
must be general purpose or weather resistant as appropriate.
(2) Where concentrations of ammonia in the air in excess of 16% by volume
are likely to be encountered, electrical equipment and wiring
must be specified by and installed according to chapter
296-307 WAC Part T, for Class I, Group D locations.
For
printing
back
to top