32 (1) The filling density of above-ground unrefrigerated tanks shall not exceed 56 per cent for uninsulated tanks and 57 per cent for insulated tanks; for volume filling at various liquid temperatures, refer to chart of figure 23, Pamphlet G-2 of Compressed Gas Association, Inc.
(2) The maximum amount of anhydrous ammonia that may be charged into a refrigerated storage container shall be that which theoretically would make the container liquid-full at a pressure equal to 120 per cent of the design pressure of the container under equilibrium conditions of temperature and pressure.
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;
28 Each tank with a water capacity exceeding 5,000 Imperial gallons should be equipped with a suitable thermometer unless some other provision is made for determining the liquid temperature.
2 In these Regulations,
filling density is the percentage figure obtained when the maximum weight of anhydrous ammonia that may be in a container is divided by the water weight capacity of the tank and the result is multiplied by 100; all capacities shall be measured at a liquid temperature of 60°F; (densité de remplissage)