OAR 437-004-0800
Storage and Handling of Anhydrous Ammonia
(1)
Scope.(a)
This standard applies to the operation of anhydrous ammonia systems including refrigerated ammonia storage systems.(b)
This standard does not apply to applications that use ammonia solely as a refrigerant.(2)
Definitions.(a)
Appurtenances — All devices such as pumps, compressors, safety relief devices, liquid-level gaging devices, valves and pressure gages.(b)
Capacity — Total volume of the container in standard U.S. gallons.(c)
Certified — See universal definitions in Subdivision 4/B, OAR 437-004-0100 (Universal Definitions).(d)
Code — The Boiler and Pressure Vessel Code, Section VIII, Unfired Pressure Vessels of the American Society of Mechanical Engineers (ASME) — 1968.(e)
Container — Includes all vessels, tanks, cylinders, or spheres used for transportation, storage, or application of anhydrous ammonia.(f)
Cylinder — A container of 1,000 pounds of water capacity or less built according to Department of Transportation specifications.(g)
Design pressure — is identical to the term “Maximum Allowable Working Pressure” used in the Code.(h)
DOT — U.S. Department of Transportation.(i)
DOT specifications — Regulations of the Department of Transportation in 49 CFR Chapter I.(j)
Farm vehicle (implement of husbandry) — A vehicle for use on a farm with a container of not more than 1,200 gallons water capacity on it.(k)
Labeled — See universal definitions in Subdivision 4/B, OAR 437-004-0100 (Universal Definitions).(l)
Listed — See universal definitions in Subdivision 4/B, OAR 437-004-0100 (Universal Definitions).(3)
Basic rules.(a)
Approval of equipment and systems. All systems, equipment and appurtenances must comply with one of the following three paragraphs.(A)
If installed before February 8, 1973, it must comply with American National Standard for the Storage and Handling of Anhydrous Ammonia, K61.1-1999 or CGA G-2.1-1999.(B)
It must be listed and labeled by a nationally recognized testing laboratory as defined in 29 CFR 1910.7.(C)
A registered engineer may test and certify custom designed and custom built systems as meeting the criteria in OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(3)(a)(A). This certification must be on file with the employer for agency review. The certification must detail the test criteria, data and results along with the qualifications of the person doing the test.(b)
Requirements for construction, original test and recertification of non-refrigerated containers.(A)
Only competent persons and/or companies may design, install and maintain non-refrigerated containers.(B)
Containers used with systems in OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(4), (7), (8) and (9) must comply with the Code (Boiler and Pressure Vessel Code, Sec VIII, Unfired Pressure Vessels of the American Society of Mechanical Engineers (ASME) — 1968). Construction under Table UW 12 at a basic joint efficiency of less than 80 percent is not authorized.(C)
Containers more than 36 inches in diameter or 250 gallons water capacity must comply with one or more of the following:(i)
Containers must be stress relieved after fabrication according to the Code; or(ii)
Cold-form heads must be stress relieved; or(iii)
Use only hot-formed heads.(D)
Paragraph (B) above does not prohibit the continued use or reinstallation of containers constructed and maintained according to the 1949, 1950, 1952, 1956, 1959, and 1962 editions of the Code or any revisions in effect at the time of fabrication.(E)
Welding to the shell, head or any other part of the container subject to internal pressure must comply with the Code. Other welding is permitted only on saddle plates, lugs or brackets attached to the container by the container manufacturer.(F)
Containers used with systems in OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(5) must comply with DOT specifications.(c)
Marking of containers. Keep the original markings on refrigerated and non-refrigerated containers as they were at the time of installation.(d)
Location of containers.(A)
When selecting the location for the storage container consider the physiological effects as well as adjacent fire hazards. Locate containers outside buildings unless the building was built for this purpose.(B)
Locate permanent storage containers 50 feet from a dug well or other sources of potable water supply, unless the container is a part of a water-treatment installation.(C)
Keep storage areas free of readily ignitible materials such as waste, weeds and long dry grass.(e)
Container appurtenances.(A)
Design appurtenances to stand the maximum working pressure of that part of the system on which they are installed. Make appurtenances from material proved suitable for anhydrous ammonia service.(B)
All connections to containers except safety relief devices, gaging devices, or those fitted with a .0550-inch orifice must have shutoff valves as close to the container as practicable.(C)
Excess flow valves where required by these standards must close automatically at the rated flows of vapor or liquid specified by the manufacturer. The connections and line including valves and fittings protected by an excess flow valve must have a larger capacity than the rated flow of the excess flow valve so that the valve will close in case of failure of the line or fittings.(D)
Liquid-level gaging devices that require bleeding of the product to the atmosphere and are built so that outward flow will not be more than that passed by a .0550-inch opening do not need excess flow valves.(E)
Openings from the container or through fittings attached directly on the container to which pressure gage connections are made need do not need excess flow valves if they are not larger than .0550-inch.(F)
Excess flow and back pressure check valves where required by this section must be inside the container or if outside as close as practicable to where the line enters the container. In the latter case installation must prevent strain beyond the excess flow or back pressure check valve from causing a break between the container and the valve.(G)
Excess flow valves must have a bypass not to exceed a .0400-inch opening to allow equalization of pressures.(H)
All excess flow valves must have plain and permanent markings with the name or trademark of the manufacturer, the catalog number, and the rated capacity.(f)
Piping, tubing and fittings.(A)
All piping, tubing and fittings must be made of material suitable for anhydrous ammonia service.(B)
All piping, tubing and fittings must be designed for a pressure not less than the maximum pressure under which they might operate.(C)
All refrigerated piping must conform to the Refrigeration Piping Code, American National Standard, B31.5-1966 with addenda B31.5a-1968 as it applies to ammonia.(D)
Piping on non-refrigerated systems must be at least American Society for Testing and Materials (ASTM) A-53-69 Grade B Electric Resistance Welded and Electric Flash Welded Pipe or equal. For welded or welded and flanged joints the pipe must be at least schedule 40. For threaded joints the pipe must be at least schedule 80. Do not back-weld threaded connections. Do not use brass, copper or galvanized steel pipe.(E)
Do not use tubing made of brass, copper, or other material subject to attach by ammonia.(F)
Do not use cast iron fittings but this does not prohibit the use of fittings made specifically for ammonia service or malleable, nodular, or high strength gray iron meeting American Society for Testing and Materials (ASTM) A47-68, ASTM 395-68 or ASTM A126-66 Class B or C.(G)
Use joint compounds that are resistant to ammonia.(g)
Hose specifications.(A)
Hose used in ammonia service must conform to the joint Agricultural Ammonia Institute — Rubber Manufacturers Association Specifications for Anhydrous Ammonia Hose.(B)
Hose subject to container pressure must be designed for a minimum working pressure of 350 p.s.i.g. and a minimum burst pressure of 1,750 p.s.i.g. Hose assemblies, when made up, must be capable of withstanding a test pressure of 500 p.s.i.g.(C)
Hose and hose connections on the low-pressure side of flow control or pressure-bleeding valves must have a bursting pressure rating of not less than five times the pressure setting of the safety relief devices protecting that part of the system but not less than 125 p.s.i.g. All connections must not leak when connected.(D)
Where using hose to transfer liquid from one container to another, “wet” hose is recommended. Such hose must have approved shutoff valves at the discharge end. Prevent excessive pressure in the hose.(E)
On all hose 1⁄2-inch outside diameter and larger, used for the transfer of anhydrous ammonia liquid or vapor, there must be etched, cast, or impressed at 5-foot intervals the following information.(h)
Safety relief devices.(A)
Every container in systems covered by OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(4), (7), (8) and (9) must have one or more safety relief valves of the spring-loaded or equivalent type. The discharge from safety-relief valves must vent away from the container, upward and unobstructed to the atmosphere. All relief-valve discharge openings must have suitable rain caps that allow free discharge of the vapor and prevent entrance of water. Accumulated condensation must drain away. The rate of the discharge must comply with Table 1.(B)
Container safety-relief valves must be set to start-to-discharge as follows, with relation to the design pressure of the container: [Table not included. See ED. NOTE.](C)
Safety relief devices in systems covered by OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(4), (7), (8) and (9) must discharge at not less than the rates in (3)(h)(A) above before the pressure is in excess of 120 percent (not including the 10 percent tolerance in (3)(h)(B) above) of the maximum permitted start-to-discharge pressure setting of the device.(D)
Arrange safety relief valves to minimize the possibility of tampering. If the pressure setting adjustment is external, the relief valves must have a means of sealing the adjustment.(E)
Shutoff valves must not be between the safety relief valves and the container; except, that a shutoff valve may be where the arrangement of this valve is such as to always afford full required capacity flow through the relief valves.(F)
Safety relief valves must have direct communication with the vapor space of the container.(G)
Each container safety relief valve used with systems covered by OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(4), (7), (8) and (9) must have plain and permanent markings with the symbol “NH3” or “AA”; with the pressure in pounds-per-square-inch at which the valve is set to start-to-discharge; with the actual rate of discharge of the valve at its full open position in cubic feet per minute of air at 60 degrees F. and atmospheric pressure; and the manufacturer’s name and catalog number.(H)
There must be no connection on either the upstream or downstream side that restricts the flow capacity of the relief valve.(I)
A hydrostatic relief valve must be between each pair of valves in the liquid ammonia piping or hose to relieve into the atmosphere at a safe location.(i)
General.(A)
All stationary storage installations must have at least two readily accessible suit- able gas masks. Full face masks with ammonia canisters, not cartridges, approved by the National Institute of Occupational and Safety and Health (NIOSH), are suitable for emergency action for most leaks, particularly those that are outdoors. For protection in concentrated ammonia atmospheres the use of self-contained breathing air apparatus is mandatory. Refer to OAR 437-004-1041 (Respiratory Protection) Respiratory Protection, Division 4/I for additional requirements for personal protective equipment.(B)
Stationary storage installations must have an easily accessible shower or a 50-gallon drum of water.(C)
Each vehicle transporting ammonia in bulk except farm applicator vehicles must carry a container of at least 5 gallons of water and a full face mask.(j)
Charging of containers.(A)
The filling densities for unrefrigerated containers must not be more than the following:(B)
Aboveground uninsulated containers may be charged 87.5 percent by volume if the temperature of the anhydrous ammonia being charged is not lower that 30 degrees F. or if the charging of the container stops at the first indication of frost or ice formation on its outside surface and does not resume until the frost or ice is gone.(k)
Transfer of liquids.(A)
Anhydrous ammonia must always be at a temperature suitable for the material of construction and the design of the receiving container.(B)
The employer must require the continuous presence of an attendant in the vicinity of the operation during ammonia transfer.(C)
Charge and use containers only with authorization of the owner.(D)
Gage and charge containers only in the open atmosphere or in buildings or areas for that purpose.(E)
Pumps used for transferring ammonia must be made for that purpose.(i)
Pumps must be designed for at least 250 p.s.i.g. working pressure.(ii)
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 of sufficient size to carry the full capacity of the pump at relief valve setting, which setting and installation must be according to the pump manufacturer’s recommendations.(iii)
On the discharge side of the pump, before the relief valve line, there must be a pressure gage graduated from 0 to 400 p.s.i.(iv)
Plant piping must have shutoff valves as close as practical to pump connections.(F)
Compressors for transferring or refrigerating ammonia must be recommended for ammonia service by the manufacturer.(i)
Compressors must be designed for at least 250 p.s.i.g. working pressure.(ii)
Plant piping must have shutoff valves located as close as practical to compressor connections.(iii)
A relief valve large enough to discharge the full capacity of the compressor must be connected to the discharge before the shutoff valve.(iv)
Compressors must have pressure gages at suction and discharge graduated to at least 1-1⁄2 times the maximum pressure.(v)
Adequate means, such as a drainable liquid trap, must be on the compressor suction to minimize the entry of liquid into the compressor.(G)
In case the hose breaks, loading and unloading systems must have suitable devices to prevent emptying of the storage or supply container. Backflow check valves or properly sized excess flow valves must be where necessary to provide this protection. If such valves are not practical, remotely operated shutoff valves may are acceptable.(l)
Tank car unloading points and operations.(A)
Unloading of tank cars must conform to the applicable recommendations in DOT regulations.(B)
The employer must insure that unloading operations are done by reliable persons properly instructed and with the authority to monitor careful compliance with all applicable procedures.(C)
Caution signs must be on the track or car to give warning to people approaching the car from the open end or ends of the siding. They must be left up until after the car is empty and disconnected from discharge connections. Signs must be metal or other suitable material, at least 12 inches by 15 inches and bear the words “STOP — Tank Car Connected” or “STOP — Men at Work” the word, “STOP,” being in letters at least 4 inches high and the other words in letters at least 2 inches high.(D)
The track of a tank car siding must be substantially level.(E)
Set the brakes and block the wheels on cars during unloading.(m)
Liquid-level gaging device.(A)
Each container except those filled by weight must have an approved liquid-level gaging device. A thermometer well must be in containers without a fixed liquid-level gaging device.(B)
All gaging devices must be arranged so that the maximum liquid level to which the container is filled is readily determined.(C)
Gaging devices that require bleeding of the product to the atmosphere such as the rotary tube, fixed tube, and slip tube devices must have a maximum opening of the bleed valve not larger than .0550-inch unless they have an excess flow valve. (This requirement does not apply to farm vehicles used for the application of ammonia as in OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(9).)(D)
Gaging devices must have a design pressure equal to or greater than the design pressure of their host container.(E)
Fixed tube liquid-level gages must indicate the container’s 85 percent fill level of its water capacity.(F)
Use columnar gage glasses only on stationary storage installations. They must have shutoff valves with metallic handwheels, excess-flow valves and extra heavy glass adequately protected with a metal housing applied by the gage manufacturer. They must be shielded from the direct rays of the sun.(n)
Electrical equipment and wiring.(A)
Electrical equipment and wiring for use in ammonia installations must be general purpose or weather resistant as appropriate.(B)
Electrical systems must comply with 4/S.(4)
Systems using stationary, non-refrigerated storage containers.(a)
Applies to all storage containers except portable DOT containers.(A)
The minimum design pressure and construction for non-refrigerated containers is 250 p.s.i.g.(B)
Each filling connection must have a combination back-pressure check valve and excess-flow valve; one double or two single back-pressure check valves; or a positive shutoff valve in conjunction with either an internal back-pressure check valve or an internal excess flow valve.(C)
All liquid and vapor connections to containers except filling pipes, safety relief connections, and liquid-level gaging and pressure gage connections with orifices not larger than .0550-inch required in OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(3)(e)(D) and (E) must have excess-flow valves.(D)
Each storage container must have a pressure gage graduated from 0 to 400 p.s.i. Gages must be designated for use in ammonia service.(E)
All containers must have vapor return valves.(b)
Safety-relief devices.(A)
Every container must have one or more safety-relief valves of the spring-loaded or equivalent type according to OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(b)(9).(B)
The rate of discharge of spring-loaded safety relief valves on underground containers may be a minimum of 30 percent of the rate of discharge in Table 1. After installation, do not uncover containers with this protection until empty of liquid ammonia. Consider containers that may contain liquid ammonia before being installed underground and before being completely covered with earth to be aboveground containers when determining the rate of discharge requirements of the safety-relief valves.(C)
On underground installations where there is a probability of the manhole or housing becoming flooded, the discharge from vent lines must be above the high water level. All manholes or housings must have ventilated louvers or their equivalent, the area which equal or exceed the combined discharge areas of safety-relief valves and vent lines that discharge their content into the manhole housing.(D)
Do not restrict vent pipes. They may not be a smaller diameter than the relief-valve outlet connection.(E)
Vent pipes from two or more safety-relief devices on the same unit, or similar lines from two or more different units may run into a common discharge header, if the capacity of the header is at least equal to the sum of the capacities of the individual discharge lines.(c)
Reinstallation of containers.(A)
Containers that were installed underground must not be reinstalled above-ground or underground, unless they withstand hydrostatic pressure retests at their original rating required by the code under which they were made. They must show no serious corrosion.(B)
Containers reinstalled aboveground, must have safety devices or gaging devices that comply with OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(i) and this paragraph respectively for above-ground containers.(d)
Installation of storage containers.(A)
Above ground containers, except as in (4)(d)(E) below must have substantial concrete or masonry supports, or structural steel supports on firm concrete or masonry foundations. All foundations must extend below the frost line.(B)
Horizontal above ground containers must be on foundations that permit expansion and contraction. Containers must have supports that prevent the concentration of excessive loads on the supporting portion of the shell. That part of the container in contact with foundations or saddles must have corrosion protection.(C)
The top of underground containers must be below the frost line and at least 2 feet below the surface. If ground conditions make compliance with these requirements impracticable, installation methods must prevent physical damage. It is not necessary to cover the part of the container where there are manhole and other connections. Anchor or weight containers when necessary to prevent floating.(D)
Underground containers must be on a firm foundation (firm earth is OK) and surrounded with compacted earth or sand. The container must have a corrosion resisting protective coating. This coating must remain undamaged when placing the container into the ground.(E)
Containers with foundations (portable or semi-portable tank containers with suitable steel “runners” or “skids” and commonly known in the industry as “skid tanks”) must comply with OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(4)(a)(A).(F)
There must be secure anchorage or adequate pier height to prevent container flotation where high flood water might occur.(G)
The distance between underground containers of over 2,000 gallons capacity must be at least 5 feet.(e)
Protection of appurtenances.(A)
Protect valves, regulators, gages and other appurtenances against tampering and physical damage. This also applies during transit of containers.(B)
All connections to underground containers must be within a dome, housing, or manhole and with access by means of a substantial cover.(f)
Damage from vehicles. Protect ammonia systems from vehicle damage.(4)
Refrigerated storage systems.(a)
Container design.(A)
The design temperature must be the minimum temperature to which the container will be refrigerated.(B)
Containers with a design pressure more than 15 p.s.i.g. must comply with OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(3)(b), and the materials must be from those in API Standard 620, Recommended Rules for Design and Construction of Large, Welded, Low-Pressure Storage Tanks, Fourth Edition, 1970, Tables 2.02, R2.2, R2.2(A), R2.2.1, or R2.3.(C)
Containers with a design pressure of 15 p.s.i.g. and less must comply with the applicable requirements of API Standard 620 including its Appendix R.(D)
Use the Code as a guide to select austenitic steels or non-ferrous materials to build containers for use at the design temperature.(E)
The filling density for refrigerated storage containers must be such that the container will not be liquid full at a liquid temperature corresponding to the vapor pressure at the start-to-discharge pressure setting of the safety-relief valve.(b)
Installation.(A)
Containers must be on suitable non-combustible foundations.(B)
There must be adequate protection against flotation or other water damage where high flood water might occur.(C)
Containers for product storage at less than 32 degrees F. must have protection from freezing and consequent frost heaving.(c)
Shutoff valves. When operating conditions make it advisable, there must be a check valve on the fill connection and a remotely operated shutoff valve on other connections below the maximum liquid level.(d)
Safety relief devices.(A)
Set safety relief valves to start-to-discharge at a pressure not more than the design pressure of the container. The valves must prevent a maximum pressure in the container of more than 120 percent of the design pressure. Relief valves for refrigerated storage containers must be self-contained spring-loaded, weight-loaded, or self-contained pilot-operated type.(B)
The total relieving capacity must be the larger of:(i)
Possible refrigeration system upset such as (1) cooling water failure, (2) power failure, (3) instrument air or instrument failure, (4) mechanical failure of any equipment, (5) excessive pumping rates.(ii)
Fire exposure determined by Compressed Gas Association (CGA) S-1, Part 3, Safety Relief Device Standards for Compressed Gas Storage Containers, 1959, except that “A” must be the total exposed surface area in square feet up to 25 feet above grade or to the equator of the storage container if it is a sphere, whichever is greater. If the relieving capacity required for fire exposure is greater than that required by OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(a), the additional capacity may be provided by weak roof to shell seams in containers operating at essentially atmospheric pressure and having an inherently weak roof-to-shell seam. The weak roof-to-shell seam is not to provide any of the capacity required in OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(a).(C)
If vent lines conduct the vapors from the relief valve, the back pressure under full relieving conditions must not be more than 50 percent of the start-to-discharge pressure for pressure balanced valves or 10 percent of the start-to-discharge pressure for conventional valves. The vent lines must prevent accumulation of liquid in the lines.(D)
The valve or valve installation must provide weather protection.(E)
Atmospheric storage must have vacuum breakers. Ammonia gas, nitrogen, methane, or other inert gases are acceptable to provide a pad.(e)
Protection of container appurtenances. Protect appurtenances against tampering and physical damage.(f)
Reinstallation of refrigerated storage containers. When reinstalling containers that require field fabrication, reconstruct and reinspect them according to their original construction requirements. Pressure retest the containers and if rerating is necessary, it must comply with applicable requirements.(g)
Damage from vehicles. Protect containers from damage by vehicles.(h)
Refrigeration load and equipment.(A)
Compute the total refrigeration load as the sum of the following:(i)
Load imposed by heat flow into the container caused by the temperature differential between design ambient temperature and storage temperature.(ii)
Load imposed by heat flow into the container caused by maximum sun radiation.(iii)
Maximum load imposed by filling the container with ammonia warmer than the design storage temperature.(B)
A single refrigeration system may serve more than one storage container.(i)
Compressors.(A)
There must be a minimum of two compressors either of which must be large enough to handle the loads. Where there are more than two compressors, there must be minimum standby equipment equal to the largest normally operating equipment. Filling compressors are acceptable as standby equipment for holding compressors.(B)
Compressors must be able to operate with a suction pressure at least 10 percent below the minimum setting of the safety valve(s) on the storage container and must withstand a suction pressure at least equal to 120 percent of the design pressure of the container.(j)
Compressor drives.(A)
Each compressor must have its individual driving unit.(B)
There must be an emergency power source that can handle the loads unless facilities are available to safely dispose of vented vapors while the refrigeration system is not operating.(k)
Automatic control equipment.(A)
The refrigeration system must have suitable controls to govern the compressor operation.(B)
There must be an emergency alarm system to function in case the container pressure rises to the maximum allowable operating pressure.(C)
An emergency alarm and shut-off must be in the condenser system to respond to excess discharge pressure caused by failure of the cooling medium.(D)
All automatic controls must be prevent operation of alternate compressors unless the controls will function with the alternate compressors.(l)
Separators for compressors. An entrainment separator of suitable size and design pressure must be in the compressor suction line of lubricated compression. The separator must have a drain and gaging device.(m)
Condensers. The condenser system may be air or water cooled or both. The condenser must have minimum design pressure of at least 250 p.s.i.g. There must be a way to purge noncondensibles either manually or automatically.(n)
Receiver and liquid drain. A receiver must have a liquid-level control to discharge the liquid ammonia to storage. The receiver must be able to operate at least 250 p.s.i.g. and have the necessary connections, safety valves, and gaging device.(o)
Insulation. Insulated refrigerated containers and pipelines must have covers of a material of suitable quality and thickness for the temperatures. Weatherproofing must be flame retardant.(5)
Systems using portable DOT containers.(a)
Cylinders must comply with DOT specifications and must comply with 49 CFR Chapter I and Marking Portable Compressed Gas Containers to Identify the Material Contained, ANSI Z48.1-1954 (R1970).(b)
Store cylinders in an area free from ignitable debris and in such manner as to prevent external corrosion. Storage may be indoors or outdoors.(c)
Cylinders filled according to DOT regulations will become liquid full at 145 degrees F. Protect cylinders from heat sources such as radiant flame and steam pipes. Do not apply heat directly to cylinders to raise the pressure.(d)
Store cylinders in a way that protects them from vehicles or external damage.(e)
Any cylinder designed to have a valve protection cap must have the cap securely in place when the cylinder is not in service.(6)
Tank motor vehicles for the transportation of ammonia.(a)
This paragraph applies to containers and equipment on tank motor vehicles including semitrailers and full trailers used to transport ammonia. This paragraph does not apply to farm vehicles. For requirements covering farm vehicles, refer to OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(8) and (9). Paragraph (b) below applies to this paragraph unless otherwise noted. Containers and pertinent equipment for tank motor vehicles for the transportation of anhydrous ammonia, must also comply with DOT requirements.(b)
Design pressure and construction of containers.(A)
The minimum design pressure for containers must comply with DOT regulations.(B)
The shell or head thickness of containers must be at least 3⁄16-inch.(C)
All container openings, except safety relief valves, liquid-level gaging devices, and pressure gages, must have labels that designate whether they communicate with liquid or vapor space.(c)
Container appurtenances.(A)
Protect appurtenances from physical damage.(B)
All connections to containers, except filling connections, safety relief devices, and liquid-level and pressure gage connections, must have suitable automatic excess flow valves, or may have quick-closing internal valves, that must remain closed except during delivery operations. The control mechanism for such valves may have a secondary control remote from the delivery connections and such control mechanism must have a fusible section (melting point 208 degrees F. to 220 degrees F.) that permits the internal valve to close automatically in case of fire.(C)
Filling connections must have automatic back-pressure check valves, excess-flow valves, or quick-closing internal valves, to prevent back-flow in case the filling connection breaks. You do not need an automatic valve where the filling and discharge connect to a common opening in the container shell and that opening has a quick-closing internal valve as in OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(f)(3)(ii).(D)
All containers must be capable of spray loading (filling in the vapor space) or with an approved vapor return valve of adequate capacity.(d)
Piping and fittings.(A)
Securely mount all piping, tubing, and fittings and protect them from damage. Protect hoses while the vehicle is moving.(B)
Fittings must comply with OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(3)(e). Pipe must be Schedule 80.(e)
Safety relief devices.(A)
The discharge from safety relief valves must vent upward away from the container and to the open air in such a manner as to prevent any impingement of escaping gas. Use loose-fitting rain caps. Size of discharge lines from safety valves must not be smaller than the nominal size of the safety-relief valve outlet connection. Condensate that accumulates in the discharge pipe must drain off.(B)
Any part of liquid ammonia piping that may close at both ends must have a hydrostatic relief valve.(f)
Transfer of liquids.(A)
Determine the content of tank motor vehicle containers by weight, by a suitable liquid-level gaging device, or other approved methods. If using a liquid-level measurement, the container must have a thermometer well. This volume when converted to weight must not be more than the filling density specified by the DOT.(B)
Any pump, except a constant speed centrifugal pump, must have a suitable pressure actuated bypass valve permitting flow from discharge to suction when the discharge pressure rises above a pre-determined point. Pump discharge must also have a spring-loaded safety relief valve set at a pressure not more than 135 percent of the setting of the bypass valve or more than 400 p.s.i.g., whichever is larger.(C)
Compressors must have manually operated shutoff valves on both suction and discharge connections. Pressure gages of bourdon-tube type must be on the suction and discharge of the compressor before the shutoff valves. The compressor must not operate if either pressure gage is removed or is inoperative. A spring-loaded, safety-relief valve capable of discharging to atmosphere the full flow of gas from the compressor at a pressure not more than 300 p.s.i.g. must be between the compressor discharge and the discharge shutoff valve.(D)
Valve functions have clear and legible identification by metal tags or nameplates permanently affixed to each valve.(g)
Full trailers and semitrailers.(A)
Securely attach full trailers to the vehicle drawing them with suitable drawbars and a safety chain (or chains) or safety cables.(B)
Every full trailer or semitrailer must have reliable brakes that operate from the driver’s seat.(C)
Every full trailer must have self-energizing brakes.(D)
Full trailers must follow substantially in the path of their towing vehicle and will not whip or swerve dangerously from side to side.(E)
Where using a fifth wheel, securely fasten it to both units, and use a positive locking mechanism that prevents separation of the two units except by manual release.(h)
Protection against collision. Each tank motor vehicle must have properly attached bumpers or chassis extension that protects the tank, piping, valves, and fittings from physical damage.(i)
Chock blocks. There must be at least two chock blocks. Use these blocks to prevent rolling during loading and unloading.(j)
Portable tank containers (skid tanks). Where these tanks are for farm storage they must comply with OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(4)(a)(A). When portable tank containers substitute for cargo tanks and are permanently on tank motor vehicles for the transportation of ammonia, they must comply with the requirements of this paragraph.(7)
Systems on farm vehicles other than for the application of ammonia.(a)
Application. This paragraph applies to containers of 1,200 gallons capacity or less and equipment on farm vehicles (implements of husbandry) not used to apply ammonia to the soil. OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(4) applies unless otherwise noted.(b)
Design pressure and classification of containers.(A)
The minimum design pressure for containers is 250 p.s.i.g.(B)
Container shell or head thickness must be at least 3⁄16-inch.(c)
Mounting containers.(A)
A suitable “stop” or “stops” must be on the vehicle or on the container so that the container does not be come loose from its mounting.(B)
At one or more places on each side of the container, a “hold down” device must anchor the container to the vehicle.(C)
When containers are on four-wheel trailers, the weight must be even over both axles.(d)
Container appurtenances.(A)
All containers must have a fixed liquid-level gage.(B)
All containers with a capacity more than 250 gallons must have a pressure gage with a dial graduated from 0-400 p.s.i.(C)
The filling connection must have a combination back-pressure check valve and excess-flow valve; one double or two single back-pressure check valves; or a positive shutoff valve in conjunction with either an internal back-pressure check valve or an internal excess flow valve.(D)
All containers with a capacity more than 250 gallons must be equipped for spray loading or have an approved vapor return valve.(E)
All vapor and liquid connections except safety-relief valves and those specifically exempted in ANSI K61.1-1966, must have approved excess-flow valves or quick-closing internal valves that, except during operating periods, must be closed.(F)
Fittings must have protection from damage by a metal box or cylinder with an open top fastened to the container or by rigid guards welded to the container on both sides of the fittings or by a metal dome. If there is a metal dome, the relief valve must vent through the dome.(G)
If there is a liquid withdrawal line in the bottom of a container, its connections, including hose, must not be lower than the lowest horizontal edge of the vehicle axle.(H)
Secure both ends of the hose while in transit.(e)
Marking the container. The words, “Caution — Ammonia” must be on each side and the rear end of the container in letters at least 4 inches high or its markings must comply with DOT regulations.(f)
Farm vehicles. All vehicles must carry a container of at least 5 gallons of water for washing ammonia from the skin.(8)
Systems on farm vehicles for the application of ammonia.(a)
This applies to systems using containers of 250 gallons capacity or less on farm vehicles (implements of husbandry) used to apply ammonia to the soil. OAR 437-004-0800 (Storage and Handling of Anhydrous Ammonia)(4) applies unless otherwise noted. Larger containers must comply with ANSI K61.1-1966.(b)
Design pressure and classification of containers.(A)
The minimum design pressure for containers is 250 p.s.i.g.(B)
The shell or head thickness of a container is less than 3⁄16-inch.(c)
Mounting of containers. All containers and flow-control devices must have secure mountings.(d)
Container valves and accessories.(A)
Each container must have a fixed liquid-level gage.(B)
The filling connection must have a combination back-pressure check valve and an excess-flow valve; one double or two single back-pressure check valves: or a positive shut-off valve in conjunction with an internal back-pressure check valve or an internal excess-flow valve.(C)
You can fill the applicator tank by venting to open air if the bleeder valve orifice is not more than 7⁄16-inch in diameter.(D)
Regulation equipment may connect directly to the tank coupling or flange only with a flexible connection between the regulating equipment and the rest of the liquid withdrawal system. Otherwise, connect the regulating equipment flexibly to the container shutoff valve.(E)
There need be no excess flow valve in the liquid withdrawal line if the controlling orifice between the contents of the container and the outlet of the shutoff valve is not more than 7⁄16-inch in diameter.
Source:
Rule 437-004-0800 — Storage and Handling of Anhydrous Ammonia, https://secure.sos.state.or.us/oard/view.action?ruleNumber=437-004-0800.