Anhydrous Ammonia Bulk Storage Regulations (C.R.C., c. 1146)

69 Smoking and the use of portable open flame lights or equipment shall be prohibited except in certain isolated and clearly-designated areas. Signs to this effect shall be posted at the plant entrances and at the loading and unloading sites. (See section 72 for restrictions applying to welding.)

70 All anhydrous ammonia installations are subject to inspection at any time by any duly-authorized officer of the Commission.

71 The owning or operating company shall report by wire to the railway company and the Director of Operation, Canadian Transport Commission, Ottawa, every fire resulting in damage to the installation, explosion, or major pipeline or tank failure occurring on the installation, and shall submit a detailed report by mail.

72 Welding shall not be permitted within 100 feet of a loading or unloading site while loading or unloading operations are in progress. At other times, welding shall only be allowed when carried out under close supervision and in accordance with the provisions of Canadian Standards Association pamphlet W-117.

• 73 (1) Each storage area with a water capacity exceeding 2,000 Imperial gallons should be protected by at least one standard fire hydrant so located that a 2½-inch hose stream may be used for controlling a fire on the site or for cooling a tank in case of adjacent fires. Consultation with the local fire authority is recommended.

• (2) Fire extinguishers suitable for small fires shall be available on installations with a storage capacity exceeding 2,000 Imperial gallons. At least one fire extinguisher shall be kept on the outside premises.

74 The principal hazards associated with the handling of anhydrous ammonia are as follows:

• (a) mixtures of air and anhydrous ammonia consisting of 16 to 25 per cent by volume of anhydrous ammonia are flammable and may ignite at a temperature as low as 1204°F in the presence of iron. For outdoor installations, this condition is not likely to be obtained except as a result of a tank or pipeline rupture. However, serious fires and explosions have occurred in which anhydrous ammonia was a contributing factor. Anhydrous ammonia becomes slightly unstable at 840-930°F and dissociates into hydrogen and nitrogen. The presence of small quantities of oil or other combustible material in anhydrous ammonia will increase the fire hazard;

• (b) 100 p.p.m. is the maximum average atmospheric concentration of ammonia to which workers may be repeatedly exposed without adverse effect on their health. Exposure to concentrations of 250 p.p.m. for 30 minutes is considered dangerous and an exposure of 30 minutes’ duration to concentrations of 5,000 p.p.m. is considered to be fatal. Industrial gas masks of a type approved for use in ammonia atmospheres should be located in a convenient place. Approximately 400 p.p.m. will cause immediate throat irritation and 700 p.p.m. will cause immediate eye irritation; and

• (c) in addition to the above-mentioned hazards, anhydrous ammonia is shipped and stored under pressure and those general safety precautions prescribed for the handling of compressed gases should be observed.

75 Safety equipment, as prescribed in the current edition of Agricultural Ammonia Institute pamphlet, Standards for the Storage and Handling of Anhydrous Ammonia should be provided at all bulk storage installations.

76 For further details, the following publications are suggested:

• (a) Standards for the Storage and Handling of Anhydrous Ammonia, by the Agricultural Ammonia Institute of Memphis, Tennessee;

• (b) Anhydrous Ammonia Pamphlet G-2, by the Compressed Gas Association, Inc., 500 Fifth Ave., New York 36, New York;

• (c) Chemical Safety Data Sheet SD-8, by the Manufacturing Chemists’ Association, Inc., 1625 Eye Street N.W., Washington 6, D.C.;

• (d) Compressed Gas Association pamphlet Safety Relief Device Standards for Compressed Gas Storage Containers, published by the Compressed Gas Association, Inc., 500 Fifth Ave., New York 36, New York; and

• (e) Liquefied Petroleum Gas pamphlets No. 58 and No. 59 by the National Fire Protection Association, 60 Batterymarch Street, Boston 10, Massachusetts.