(a)

1. (1) Couplings and external flanges used on any container shall be welded both inside and outside.
2. (2) The use of nipples in lieu of couplings or flanges is prohibited.
3. (3) All couplings, piping, and valves shall be wrought iron or steel.
4. (4) The use of cast iron, copper, brass, or galvanized fittings is prohibited.

(b)

1. (1) All containers shall be equipped with necessary safety relief valves, filler valves, vapor return valves, liquid level gauge, outage gauge, and a pressure gauge graduated from zero (0) to four hundred (400).
2. (2) The vapor return valve, filler valve, and liquid outlet valve shall be equipped with excess flow check valves.
3. (3) It is not required that dispensing units be equipped with excess flow check valves in the liquid outlet.
4. (4) Safety relief valves shall have direct communication with the vapor space of the container.

(c)

1. (1) All fittings to be attached to an anhydrous ammonia container of any type (liquid or vapor) shall be approved for use with anhydrous ammonia and designed for not less than the maximum pressure to which they may be subjected.
2. (2) Valves which may be subjected to container pressure shall have a rated working pressure not less than two hundred fifty pounds per square inch gauge (250 psig).

(g) All excess flow valves shall be plainly and permanently marked with the:

1. (1) Name or trademark of the manufacturer;
2. (2) Catalog number; and
3. (3) Rated capacity.

(i)

1. (1) Excess flow and back-pressure check valves shall be located inside the container or at a point outside where the line enters the container.
2. (2) In the latter case, installation shall be made in such a manner that any undue strain, beyond the excess flow or back-pressure check valve, will not cause breakage between the container and the valve.

(j) Each filling connection or valve shall be fitted with one (1) of the following:

1. (1) Combination back-pressure check valve and excess flow valve;
2. (2) One (1) double or two (2) single back-pressure check valves; or

3. (3) A positive shutoff valve, in conjunction with either:

   1. (A) An internal back-pressure valve; or
   2. (B) An internal excess flow valve.