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Subchapter 7. General Industry Safety Orders
Group 10. Gas Systems for Welding and Cutting
Article 86. Manifolding of Cylinders to Headers for Shop Pipe Line Supply Systems and Pressure Reducing Regulators and Hose

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§4834. Manifolds, General.

(a) Manifolds shall be approved either separately for each component part or as an assembled unit.

(b) Each fuel-gas and oxygen cylinder lead shall be provided with a backflow check valve.

(c) The aggregate capacity of fuel-gas cylinders connected to a portable manifold inside a building shall not exceed 3,000 cubic feet of gas.

(d) Acetylene and liquefied fuel-gas cylinders shall be manifolded in a vertical position.

(e) Such manifolds shall be so located and so guarded as to protect them against damage from trucks and from any material being moved in the vicinity.

(f) Cylinder manifolds shall be installed under the supervision of someone familiar with the proper practices with reference to their construction and use.

(g) All component parts used in the methods of manifolding described in Section 4821 shall be approved as to materials, design and construction either separately or as an assembled unit.

(h) All manifolds and parts used in methods of manifolding shall be used only for the gas or gases for which they are approved.

(i) When acetylene cylinders are coupled, approved flash arresters shall be installed between each cylinder and the coupler block. For outdoor use only, and when the number of cylinders coupled does not exceed three, one flash arrester installed between the coupler block and regulator is acceptable.

(j) Fuel gas and oxygen manifolds shall bear the name of the substance they contain in letters at least 1-inch high which shall be either painted on the manifold or on a sign permanently attached to it.

(k) Fuel gas and oxygen manifolds shall be placed in safe, well ventilated, and accessible locations. They shall not be located within enclosed spaces.

(l) Nothing shall be placed on top of a manifold, when in use, which will damage the manifold or interfere with the quick closing of the valves.

NOTE: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


1. Repealer and new section filed 5-16-75; effective thirtieth day thereafter (Register 75, No. 20).

2. Amendment of subsection (b) filed 7-13-78; effective thirtieth day thereafter (Register 78, No. 28).

3. Amendment of subsection (a) filed 6-12-87; operative 7-12-87 (Register 87, No. 26).

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