Labor & Industries (L&I), Washington State

Anhydrous Ammonia Chapter 296-826, WAC

Effective Date: 09/01/06

WAC 296-826-400 Equipment and Systems

For printing

YOUR RESPONSIBILITY:

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

Electrical	WAC 296-826-40005
Hose specifications	WAC 296-826-40010
PIPING, TUBING, AND FITTINGS
General requirements for all systems	WAC 296-826-40015
Nonrefrigerated systems	WAC 296-826-40020
Systems mounted on trucks, semi-trailers, and trailers	WAC 296-826-40025
REFRIGERATION STORAGE
Refrigerated storage compressors	WAC 296-826-40030
Refrigeration load	WAC 296-826-40035
Separators for refrigerated storage	WAC 296-826-40040
Automatic control equipment for refrigerated storage	WAC 296-826-40045
Other refrigerated storage equipment	WAC 296-826-40050
Compressors for refrigerated systems	WAC 296-826-40055

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: 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: 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.