46 CFR §147.60

1. (a)Cylinder requirements. Cylinders used for containing hazardous ships' stores that are compressed gases must be—
   1. (1)Authorized for the proper shipping name of the gas in accordance with 49 CFR 172.101 and 49 CFR part 173;
   2. (2)Constructed in accordance with subpart C of 49 CFR part 178 or exempted under 49 CFR part 107;
   3. (3)Filled, marked, and inspected in accordance with 49 CFR 173.301 through 173.308; and
   4. (4)Except as provided in 46 CFR 147.65, 147.66, and 147.67, maintained and retested in accordance with 49 CFR 180.
2. (b)Stowage and care of cylinders.
   1. (1)Cylinders must always be secured and, when not in use, they must be stowed in a rack in an upright position, with the valve protection cap in place.
   2. (2)Lockers or housings must be vented to the open air near the top and bottom for positive circulation of vapors.
   3. (3)Cylinders must be protected from all sources of heat which may cause the cylinders to be heated to a temperature higher than 130 °F.
3. (c)Pressure vessels other than cylinders. Pressure vessels, other than cylinders subject to paragraph (a) of this section, used for containing ships' stores that are compressed gases must—
   1. (1)Be constructed and inspected in accordance with part 54 of this chapter; and
   2. (2)Carry only nitrogen or air, unless permission is granted by Commandant (CG-ENG) to do otherwise.