Vaporizers and any part thereof and other devices that may be subjected to container pressure shall have a design pressure of at least 250 p.s.i.g.
Vaporizers shall be securely fastened so as to minimize the possibility of becoming loosened.
Each vaporizer shall be permanently marked at a visible point as follows:
With the design pressure of the fuel-containing portion in p.s.i.g.
With the water capacity of the fuel-containing portion of the vaporizer in pounds.
Devices to supply heat directly to a fuel container shall be equipped with an automatic device to cut off the supply of heat before the pressure inside the fuel container reaches 80 percent of the start to discharge pressure setting of the safety relief device on the fuel container.
Engine exhaust gases may be used as a direct source of heat supply for the vaporization of fuel if the materials of construction of those parts of the vaporizer in contact with exhaust gases are resistant to the corrosive action of exhaust gases and the vaporizer system is designed to prevent excessive pressures.
Vaporizers shall not be equipped with fusible plugs.
Each vaporizer shall have a valve or suitable plug which will permit substantially complete draining of the vaporizer. It shall be located at or near the lowest portion of the section occupied by the water or other heating medium.