1. For requirements on agricultural operations using anhydrous ammonia, go to Part U-1 of chapter 296-307 WAC.

 

2. If you use, handle, store, distribute, or transport anhydrous ammonia in quantities of 10,000 pounds or more, follow the requirements found in another chapter, Process safety management of highly hazardous chemicals, chapter 296-67 WAC.

 

3. To protect employees handling ammonia, in addition to this chapter, you will need the following requirements found in other chapters:

 

a. The following sections from the Safety and health core rules, chapter 296-800 WAC:

 

i. Accident prevention program, WAC 296-800-140;

 

ii. Emergency washing, WAC 296-800-150;

 

iii. Personal protective equipment, WAC 296-800-160.

 

b. Emergency response, chapter 296-824 WAC;

 

c. Respiratory hazards, chapter 296-841 WAC;

 

d. Respirators, chapter 296-842 WAC.

Additional safety equipment is recommended when more than one employee is present.

Under some circumstances, ammonia and ammonium compounds can form explosive products with other chemicals. For additional information, refer to the following:

 

1. Section 491M "Manual on Hazardous Chemical Reactions" of the NFPA, 1969 Edition; and

 

2. CG-388, the "Chemical Data Guide for Bulk Shipment by Water," 1969.

Drivers unable to stop a leak during transport should:

 

1. Move the vehicle to an isolated area.

 

2. Use the current Department of Transportation (DOT) Emergency Response Guidebook to establish safe distances to isolate a leaking tank from the driver and the public.

If the container is a part of a water treatment installation, this requirement does not apply.

1. It is recommended that the ground in an impounding basin or within a diked enclosure be graded so that small spills or the early part of a large spill will accumulate at one side or corner contacting both:

 

a. A relatively small area of ground; and

 

b. Exposing a relatively small surface area for heat gain.

 

2. Shallow channels in the ground surface or low curbs of earth can help guide the liquid to these low areas without contacting a large ground area.

Emergency power is not necessary for facilities able to effectively vent vapors when the refrigeration system is not operating.

Condensers may be cooled by any of the following:

 

1. Air;

 

2. Water;

 

3. Air and water.

The rate of discharge of spring-loaded safety relief valves installed on underground containers may be reduced to thirty percent of the rate of discharge specified in Table 6, Safety Relief Valve Rate of Discharge so long as the container is not uncovered after installation until the liquid ammonia has been removed.

A relief valve manufacturer's tolerance of plus ten percent is permitted.

Vent pipes from 2 or more safety relief devices located on the same unit, or similar lines from 2 or more different units, may be run into a common header if the cross-sectional area of the header is at least equal to the sum of the cross sectional areas of the individual vent pipes.

You are exempt from the requirement not to install the shut off valve between the safety relief valve and the container or systems in the following situations:

 

1. A three-way valve installed under two safety relief valves, each with:

 

a. The required rate of discharge; and

 

b. Installed to allow either of the safety relief valves to be closed off but not at the same time.

 

2. Two separate relief valves are installed with individual shut off valves.

 

3. The two shut off valve stems must be mechanically interconnected to allow the full required flow of one safety relief valve at all times.

 

4. When a safety relief valve manifold that allows:

 

a. One valve of two or more to be closed off; and

 

b. The remaining valve or valves will provide not less than the rate of discharge shown on the manifold nameplate.

The following do not need to be fitted with excess flow valves:

 

1. Safety relief valves.

 

2. Liquid level gauging devices that require both of the following:

 

a. Bleeding of the product into the atmosphere;

 

b. Construction so that outward flow will not exceed that passed by a No. 54 drill size opening.

 

Those with openings from the containers or through fittings that are attached directly onto the container where pressure gauge connections are made as long as: The openings are not larger than a No. 54 drill size.

Shut off valves do not need to be provided on connections with a No. 54 drill size restriction.

Install, when operating conditions make it advisable, both of the following:

 

1. A check valve on the fill connection;

 

2. A remotely operated shut off valve on other connections located below the maximum liquid level.

You are exempt from the requirement not to install the shut off valve between the safety relief valve and the container or systems in the following situations:

 

1. A three-way valve installed under two safety relief valves, each with:

 

a. The required rate of discharge; and

 

b. Installed to allow either of the safety relief valves to be closed off but not at the same time.

 

2. Two separate relief valves are installed with individual shut off valves.

 

3. The two shut off valve stems must be mechanically interconnected to allow the full required flow of one safety relief valve at all times.

 

4. When a safety relief valve manifold that allows:

 

a. One valve of two or more to be closed off; and

 

b. The remaining valve or valves will provide not less than the rate of discharge shown on the manifold nameplate.

The following do not need to be fitted with excess flow valves:

 

1. Safety relief valves;

 

2. Those with openings from the containers or through fittings that are attached directly onto the container where pressure gauge connections are made as long as the openings are not larger than a No. 54 drill size.

You are exempt from the requirement not to install the shut off valve between the safety relief valve and the container or systems in the following situations:

 

1. A three-way valve installed under two safety relief valves, each with:

 

a. The required rate of discharge; and

 

b. Installed to allow either of the safety relief valves to be closed off but not at the same time.

 

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.

 

3. When a safety relief valve manifold that allows:

 

a. One valve of two or more to be closed off; and

 

b. The remaining valve or valves will provide not less than the rate of discharge shown on the manifold nameplate.

You are exempt from the requirement not to install the shut off valve between the safety relief valve and the container or systems in the following situations:

 

1. A three-way valve installed under two safety relief valves, each with:

 

a. The required rate of discharge; and

 

b. Installed to allow either of the safety relief valves to be closed off but not at the same time.

 

2. Two separate relief valves are installed with individual shut off valves.

 

3. The two shut off valve stems must be mechanically interconnected to allow the full required flow of one safety relief valve at all times.

 

4. When a safety relief valve manifold that allows:

 

a. One valve of two or more to be closed off; and

 

b. The remaining valve or valves will provide not less than the rate of discharge shown on the manifold nameplate.

Two "g" is either of the following:

 

1. For load support it is equivalent to three times the static weight of the supported articles.

 

2. For loading and bending, acceleration, and torsion it is equivalent to twice the static weight support applied horizontally at the road surface.

If such valves are not practical, remotely operated shut off valves may be installed.

For uninsulated, aboveground containers, the 56% corresponds to:

 

1. 82% by volume at -28°F.

 

2. 85% by volume at 5°F.

 

3. 87.5% by volume at 30°F.

 

4. 90.6% by volume at 60°F.