1. (a) Vaporizers shall have their correctness as to design, construction, and performance certified as follows: Constructed in accordance with the requirements of the American Society of Mechanical Engineers Unfired Pressure Vessel Code, Underwriters Laboratories, Inc., American Gas Association, approval through tests by any other competent laboratory recognized by the Liquefied Petroleum Gas Board.

2. (b) Indirect fired vaporizers utilizing steam, water, or other heated medium shall be:

   1. (1) Constructed in accordance with the requirements of the American Society of Mechanical Engineers Unfired Pressure Vessel Code; and

   2. (2) Permanently marked as follows:

      1. (A) With the code markings signifying the specifications to which the vaporizer is constructed;
      2. (B) With the allowable working pressure and temperature for which the vaporizer is designed; and
      3. (C) With the outside surface and the inside heat exchange surface expressed in square feet.

3. (c) Vaporizers having an inside diameter of six inches (6”) or less exempted by the ASME Unfired Pressure Vessel Code shall:

   1. (1) Have a designed working pressure of not less than two hundred fifty pounds per square inch gauge (250 psig); and
   2. (2) Need not be permanently marked.

4. (d) Vaporizers may be an integral part of a fuel storage container directly connected to the:

   1. (1) Liquid section;
   2. (2) Gas section; or
   3. (3) Both.
5. (e) Vaporizers may be installed in buildings, rooms, sheds, or lean-tos used exclusively for gas manufacturing or distribution, or in other structures of light, fire resistive construction or equivalent, well-ventilated near the floor line and roof constructed for the purpose of housing the vaporizer.
6. (f) Vaporizers shall have at or near the discharge a safety relief valve providing an effective rate of discharge in accordance with the latest edition of National Fire Protection Association Pamphlet No. 58.
7. (g) Vaporizers shall be provided with suitable automatic means to prevent liquid passing from the vaporizers to the gas discharge piping.

8. (h)

   1. (1) The device that supplies the necessary heat for producing steam, hot water, or other heating medium may be installed in a building, compartment, room, or lean-to which shall be ventilated near the floor line and roof to the outside.

   2. (2) This device location shall be separated from all compartments or rooms containing liquefied petroleum gas vaporizers, pumps, and central gas mixing devices by:

      1. (A) A wall of substantially fire-resistant material; and
      2. (B) Vapor tight construction.
   3. (3) This requirement does not apply to the domestic water heaters which may supply heat for a vaporizer in a domestic system.
9. (i) Gas fired heating systems supplying heat exclusively for vaporization purposes shall be equipped with automatic safety devices to shut off the flow of gas to main burners if pilot light should fail.

10. (j) Atmospheric vaporizers employing heat from the ground or surrounding air shall be installed as follows:

    1. (1) Buried underground, or located inside building close to a point at which pipe enters the building provided capacity of unit does not exceed one quart (1 qt.); and
    2. (2) Vaporizers of less than one quart (1 qt.) capacity, heated by the ground or surrounding air, need not be equipped with safety relief valves provided that adequate tests certified by any of the authorities listed in subsection (a) of this section demonstrate that the assembly is safe without safety relief valves.
11. (k) Vaporizers designed primarily for domestic service shall be protected against tampering and mechanical injury.

12. (l) No gas in the liquid phase shall be piped into any building for fuel purposes except:

    1. (1) Buildings devoted exclusively to housing equipment for vaporization, pressure reduction, gas mixing, gas manufacturing, or distribution;
    2. (2) Buildings, or separate fire divisions of buildings, used exclusively to house internal combustion engines or industrial processes; or

    3. (3)

       1. (A) In domestic installations no liquid or gas shall be piped into a building at a pressure of more than twenty pounds per square inch gauge (20 psig).
       2. (B) The initial pressure reducing devices shall be installed outside the building.
13. (m) No vaporizer shall be equipped with fusible plugs.
14. (n) In industrial and gas manufacturing plants, safety relief valves on vaporizers within a building shall be piped to a point outside the building and be discharged upward.

Codification Notes: “ASME” means American Society of Mechanical Engineers.