Anhydrous Ammonia

Chapter 296-826, WAC

Effective Date: 09/01/06

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WAC 296-826-400

Equipment and Systems

For printing

YOUR RESPONSIBILITY:

To make sure all equipment and systems are operated and maintained safely

Electrical

Hose specifications

PIPING, TUBING, AND FITTINGS

General requirements for all systems

Nonrefrigerated systems
Systems mounted on trucks, semi-trailers, and trailers
REFRIGERATION STORAGE

Refrigerated storage compressors

Refrigeration load
Separators for refrigerated storage

Automatic control equipment for refrigerated storage

Other refrigerated storage equipment

Compressors for refrigerated systems

WAC 296-826-40005

Electrical

You must

  • Use electrical equipment and wiring on ammonia installations that's either of the following:
    • -General purpose
      or
    • -Weather resistant.
  • Follow the electrical requirements found in another chapter, Chapter 296-24 WAC, Part L for Class 1, Group D locations when the concentrations of ammonia in air are in excess of 16% by volume.

 

WAC 296-826-40010

Hose specifications

You must

  • Make sure hose used in ammonia service and subject to container pressure meets both of the following:
    • -The Joint Rubber Manufacturers Association, RMA-IP-14, Specifications for Anhydrous Ammonia Hose 7th Edition 2003
      and
    • -The Fertilizer Institute "Hose Specifications for Anhydrous Ammonia."
  • Make sure hose assemblies are able to withstand a 500 psig pressure test.
  • Follow Table 4 for hose specifications.
Table 4
Hose Specifications

If you have

Then

Hose subject to container pressure

  • Design it with a minimum
    • -Working pressure of 350 psig
      and
    • -Burst pressure of 1750 psig

Hose and their connections

  • Design them for the maximum low side working pressure when located on either:
    • -The pressure reducing valves on devices discharging to atmospheric pressure
      or
    • -The low pressure side of flow control.
  • Design, construct, and install so there's no leakage when connected.

Liquid transfer hose that isn't drained of liquid upon completion of transfer operations

  • Equip with an approved shut off valve at the discharge end.
  • Prevent excessive hydrostatic pressure in the hose.

Hose with an outside diameter one-half inch and larger

Make sure the hose is marked and legible at 5 foot intervals.

PIPING, TUBING, AND FITTINGS

WAC 296-826-40015

General requirements for all systems

You must

  • Prohibit the use of cast iron fittings.
    • -The use of malleable or nodular iron such as Specification ASTM A47 or ASTM A395 is permitted.
  • Make sure all metal flexible connections for permanent installations have a minimum working pressure of 250 psig
  • Make sure all pipes, tubes, and fittings used for ammonia service meet all of the following:
    • -Made of material with a design pressure at least equal to the maximum service pressure.
    • -Well supported and have provisions for all of the following:
      • Expansion
      • Contraction
      • Vibration
      • Jarring
      • Settling.
  • Protect all exposed pipes from damage resulting from undue strain including:
    • -Moving machinery
    • -The presence of vehicles.
  • Use ammonia resistant joint compounds.
  • Make sure, after assembly, that all piping and tubing are leak free at a pressure not less than the normal operating pressure of the system.

WAC 296-826-40020

Nonrefrigerated systems

You must

  • Make sure piping on nonrefrigerated systems is:
    • -ASTM A-53-2004 Electrical Resistance Welded and Electric Flash Welded Pipe or equal. In addition piping needs to be:
      • At least schedule 80 when joints are threaded.
      • At least schedule 40 when joints are either welded or welded and flanged.
  • Prohibit the use of piping or tubing made of any of the following:
    • -Brass
    • -Copper
    • -Galvanized steel.

WAC 296-826-40025

Systems mounted on trucks, semi-trailers, and trailers

You must

  • Make sure all piping, tubing, and fittings are:
    • -Securely mounted
    • -Protected against physical damage.

REFRIGERATED STORAGE

WAC 296-826-40030

Refrigerated storage compressors

You must

  • Make sure compressors have all of the following:
    • -Their own driving unit
    • -Discharge pressure that's governed by the condensing conditions
    • -Suitable compressor operation controls based on the load pressure in the container
    • -At least 2 compressors either of which is of sufficient size to handle the intended loads
    • -Standby equipment equal to the largest normally operating piece of equipment installed when more than 2 compressors are provided
    • -Automatic controls installed to prohibit the operation of alternate compressors unless the controls will function with alternate compressors.
  • Make sure compressors are sized to operate with a suction pressure that's both of the following:
    • -At least 10 percent below the minimum setting of the safety relief valves on the storage tank
    • -Able to withstand 120 percent of the design pressure of the tank.
  • Install an oil separator of suitable size in the compressor discharge line that's both:
    • -Designed for at least 250 psig;
      and
    • -Equipped with a drain valve and gauging device.

WAC 296-826-40035

Refrigeration load

You must

  • Make sure the total refrigeration load includes the loads imposed by all of the following:
    • -Heat flow into the container caused by the temperature difference between both:
      • The ambient temperature
        and
      • The design storage temperature
    • -Heat flow into the tank caused by maximum sun radiation
    • -Filling the tank with ammonia warmer than the design storage temperature.
  • Provide emergency power capable of handling loads imposed by both of the following:
    • -The temperature difference between the ambient temperature and the design storage temperature
      and
    • -Sun radiation.

 

Note

Note:

Emergency power isn't necessary for facilities able to effectively vent vapors when the refrigeration system isn't operating.

WAC 296-826-40040

Separators for refrigerated storage

You must

  • Install an entrainment separator, of suitable size and design pressure, in the compressor suction line that's equipped with both of the following:
    • -A drain valve
      and
    • -A gauging device.

WAC 296-826-40045

Automatic control equipment for refrigerated storage

You must

  • Install an emergency alarm to detect minimum and maximum allowable operating pressure changes.
  • Install an emergency alarm and shut off in the condenser system to detect excess discharge pressure caused by the failure of the cooling medium.

WAC 296-826-40050

Other refrigerated storage equipment

You must

  • Discharge ammonia to storage by using either:
    • -A receiver with an automatic float valve
      or
    • -A high pressure liquid drain trap of suitable capacity.
  • Make sure receivers are:
    • -Designed for at least 250 psig
      and
    • -Equipped with all of the following:
      • Necessary connections
      • Safety relief valves
      • Gauging devices.
  • Cover insulated containers and pipelines with material that meets all of the following:
    • -Thick enough for the temperatures it will be exposed to
    • -Supported
    • -Weather and fire resistant.

WAC 296-826-40055

Compressors for refrigerated systems

You must

  • Make sure condensers are designed:
    • -For at least 250 psig
      and
    • -To manually or automatically purge noncondensibles.

Note

Note:

  • Condensers may be cooled by any of the following:
    • -Air
    • -Water
    • -Air and water.

You must

  • Make sure compressors used for refrigerating ammonia meet all of the following:
    • -Are connected to plant piping with shut off valves located as close as practical to compressor connections
    • -Have a safety relief valve that is both:
      • Large enough to discharge the full capacity of the compressor
        and
      • Connected to the discharge and placed before any shut off valve
    • -Have an oil separator on the discharge side, where necessary to prevent contamination.
    • -Have a drainable liquid trap or other adequate method on the compressor suction to minimize the entry of liquids into the compressor.
    • -Pressure gauges on the suction and discharge ends graduated to at least one and one-half times the maximum pressure that can develop.

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