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Subchapter 1. Unfired Pressure Vessel Safety Orders
Article 2. Design and Construction

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§457. Design and Construction of LNG Vaporizers.

(a) LNG Vaporizers:

(1) Vaporizers having a volumetric capacity in excess of 1 U.S. gallon shall be either:

(A) Constructed, inspected and stamped in accordance with the ASME Code unless the design and construction of the vaporizer are accepted by the Division as equivalent to ASME Code, or;

(B) Fabricated and tested in accordance with ANSI B-31.3 when artificial heat is not used for vaporization and when of welded construction consisting of continuous pipe or tubing and fittings not exceeding 6 inches inside diameter, or;

(C) Made of threaded piping and pipe fittings and built to good engineering practice with a factor of safety of not less than 4, taking into account all imposed loadings.

(2) Vaporizers and any part thereof, including carbureting devices, shall be designed for minimum as well as maximum temperatures and the maximum pressure that can be imposed with a safety factor of at least 4.

(3) Vaporizers having a volumetric capacity in excess of 1 U.S. gallon shall be stamped with the information required by the ASME Code and shall also include:

(A) Head and shell thicknesses.

(B) The words "For LNG."

(C) Heat exchange surface in square feet.

(D) The vaporizer capacity per hour in U.S. gallons.

(E) Minimum safety relief valve capacity in CFM air. (See Section 540(c) .)

(b) Vaporizers made of pipe or tubing shall have a nominal diameter of 2 inches or less and shall have the information required in (C) , (D) and (E) above stamped on the nameplate which shall be permanently attached to the vaporizer. This nameplate shall also show the manufacturer's name, year built and maximum allowable working pressure.

Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 13241, Health and Safety Code.


1. Amendment filed 12-8-72 as procedural and organizational; effective upon filing (Register 72, No. 50).

2. Amendment filed 11-7-75; effective thirtieth day thereafter (Register 75, No. 45).

3. Amendment filed 1-5-88; operative 2-4-88 (Register 88, No. 4).

. 4. Amendment of section heading, repealer of subsections (a)-(a)(5), subsection relettering, and amendment of NOTE filed 12-4-96; operative 1-3-97 (Register 96, No. 49).

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