California Code of Regulations
Title 13 - Motor Vehicles
Division 2 - Department of the California Highway Patrol
Chapter 4 - Special Equipment
Article 2 - Compressed and Liquefied Gas Fuel Systems
Section 936 - Installation

Universal Citation: 13 CA Code of Regs 936

Current through Register 2024 Notice Reg. No. 38, September 20, 2024

The installation of liquefied petroleum gas, compressed natural gas, or liquefied natural gas fuel systems on motor vehicles equipped with gaseous fuel systems certified or approved by the State Air Resources Board shall be in accordance with the following requirements:

(a) Driver, Passenger, and Luggage Compartments. Fuel supply containers on buses shall not be located in or above the passenger compartment. Fuel supply containers on vehicles other than buses shall be installed and fitted so that no gas from fueling and gaging operations or from relief valves can be released inside the driver, passenger, or luggage compartments.

(b) Fuel Supply Containers. Fuel supply containers shall meet all appropriate requirements of the ASME code, the DOT regulations, or the regulations contained in this article and shall be marked in accordance with Sections 933, 934, and 935 of this article. Cargo containers mounted on a motor vehicle, but not on a trailer or semitrailer, may be used to supply fuel for the propulsion of the vehicle when the container meets the cargo container requirements of Unfired Pressure Vessel Safety Orders, Division of Industrial Safety, Title 8, California Code of Regulations. Fuel supply containers other than cargo containers shall comply with the following requirements:

(1) Each container and container cradle shall be mounted in protected locations to minimize damage from collision.

(2) To prevent damage from road hazards, slippage, loosening, or rotation, each container or cradle shall be secured to the vehicle body, bed, or frame by either of the following means:
(A) By attaching bolts not less than 7/16 in. in diameter that meet SAE Standard J429 for Grade 5 threaded fasteners in the 1965 or later edition of the SAE Handbook and self-locking nuts to at least four securement points and, where bolts pierce body metal but not the frame, by reinforcing both sides of each securement point with metal plates at least 1/8 in. thick and 7 sq. in. in area; or

(B) By using other means capable of withstanding in any direction a static force of eight times the weight of the fully loaded container.

(3) Each container in a cradle shall be secured to its cradle by means capable of withstanding in any direction a static force of eight times the weight of the fully loaded container.

(4) No portion of the container or container valves in communication with the liquid or vapor shall be located behind the rear frame crossmember of the vehicle.

(5) The weight of the container shall not in any way be supported by outlets, valves, manifold, or other fuel connections.

(6) No part of the container shall be field welded. Only saddle plates, brackets, or other nonpressure parts that were provided and installed by the manufacturer of the container may be field welded.

(7) No container shall be repaired until the contemplated repair has been authorized by a certified inspector. DOT containers shall be repaired under DOT regulations and control. The replacement of valves, fittings, and accessories intended for the same purpose is not considered a repair.

(8) Containers located less than 8 in. from the engine or exhaust system shall be shielded against direct heat.

(c) Visibility of Required Markings. Markings of set-to-discharge pressure for safety relief devices and working pressure of fuel supply containers required by Sections 933, 934, and 935 of this article shall be visible either directly or by use of a mirror after installation. All remote filling inlets shall be visibly marked with the lowest working pressure of any fuel supply container in the system.

(d) Discharge Lines and Outlets. All safety devices that may discharge to the atmosphere shall be vented to the outside of the vehicle, and all discharge lines and outlets shall be installed as follows:

(1) Lines shall be constructed of metal other than aluminum and shall be of a size and so located and maintained as not to restrict the maximum gas flow of the safety device. Flexible metallic lines shall be used when necessary.

(2) The discharge line of a container installed inside a compartment shall extend to the outside of the compartment.

(3) Lines shall be located as far from the exhaust outlet as is practicable and shall direct escaping gas upward within 45 deg. of the vertical. Escaping gas shall not impinge upon fuel supply containers and shall not be directed into wheel wells, at other vehicles in traffic, or at engine air intake inlets.

(4) The discharge line from the safety relief valve on all buses shall be located at the rear of the vehicle, directed upward, and extended to the top of the vehicle roof.

(5) Outlets shall be protected by caps, covers, or other means to keep water or dirt from collecting in the lines. Protective devices shall not restrict the flow of gas.

(6) Each line and its connectors shall withstand the pressure caused by the discharge of vapor or liquid from a safety device in fully open position.

(7) CNG containers may be vented to the outside of the vehicle with a flexible bag. Such bag shall be constructed of material that is nonflammable or self-extinguishing. The bag and attachments shall be capable of withstanding an internal pressure produced by a flow rate of 300 cfm with a safety factor of not less than four. The bag shall be shielded or installed in a protected location to prevent damage from unsecured objects and abrasion.

(e) Manifolds. Manifolds connected to fuel containers shall be supported to minimize vibration and shall be installed in a protected location or shielded to prevent damage from unsecured objects.

(1) A manual shut-off valve shall be installed in the outlet of the manifold and marked with the words "MANUAL SHUT-OFF VALVE." (Decals or stencils are acceptable.)

(2) A normally closed automatic shut-off valve that is held open by electrical current may be used in lieu of a manual shut-off valve and shall be marked with the words "AUTOMATIC SHUT-OFF VALVE." The automatic shut-off valve shall be wired so it shuts off when the ignition switch is in the off or accessory positions and when engine vacuum is not present.

(f) Pipes, Tubing, Hose, and Fittings. All pipes, tubing, hoses, and fittings shall meet the following requirements:

(1) All materials and assemblies shall be designed for the widest pressure and temperature ranges to which they may be subjected with a pressure safety factor of at least four.

(2) All material, including gasket and packing material, shall be compatible with the fuel used in the system and its service conditions. Aluminum pipe, tubing, or fittings shall not be used between the container and first-stage regulator. Copper tubing, when used, shall be seamless and conform to ASTM B88 types K or L.

(3) A pipe thread sealant impervious to the action of the fuel used in the system shall be applied to all male pipe threads prior to assembly. Only tin-silver (95% tin, 5% silver) or silver braze alloy is permitted on sweat type joints or fittings.

(g) Supply Lines. Supply lines passing through a panel shall be protected by grommets or similar devices, which shall snugly fit both the supply lines and the holes in the panel. Supply lines shall have a minimum clearance of 8 in. from the engine exhaust system unless they are shielded from exhaust heat. Supply lines shall be supported at least every 24 in. and shall be prevented from sagging. Damaged lines shall be replaced, not repaired.

(h) Automatic Fuel Supply Shut Off. An automatic fuel supply shut-off valve shall be installed in a protected location adjacent to the manual shut-off valve on all buses and shall be activated by engine vacuum or oil pressure.

(i) Gaseous Fuel Cutoff. Means shall be provided in the system to prevent the flow of gaseous fuel to the carburetor when the ignition is in the off or accessory position, or from the carburetor when engine vacuum is not present.

(j) Liquid Fuel Cut Off. Dual fuel systems using liquid and gaseous fuel shall have an automatic shut-off valve installed in the liquid fuel line to the carburetor.

(k) Bypass Relief Device. A bypass relief device shall be installed in the fuel pump or between the fuel pump and the automatic shut-off valve in the liquid fuel line to the carburetor on vehicles equipped with dual fuel systems for the use of gasoline and gaseous fuel. The relief device need not be installed on fuel pumps containing a bypass relief device as original equipment.

(l) Engine Exhaust Outlet. The engine exhaust system shall extend to the outer edge of the vehicle body or bed on passenger cars, station wagons, house cars, pickup trucks with campers, buses, and delivery vans.

(m) Electrical Equipment. Radio transmitters, radio receivers, electric motors, or other electrical equipment (except vehicle lamps and wiring) shall not be mounted in a compartment with fuel supply containers unless one of the following conditions is met:

(1) All piping and all connectors and valves on the fuel supply containers are exterior to and sealed from the compartment containing electrical equipment, or

(2) All piping, connectors, and valves within the compartment are contained in a vapor-tight enclosure and vented to the atmosphere exterior of the vehicle, or

(3) The electrical equipment is contained in a vapor-tight enclosure that is vented to the atmosphere exterior of the vehicle, or

(4) The electrical equipment is approved for use in Class I, Division II, "Hazardous Locations," in accordance with Article E501, Title 24, California Code of Regulations.

(n) Road Clearance. The fuel system, including the fuel supply container, shall be installed with as much road clearance as practicable. The lowest part of any component in the system, including protective guards, shall not be lower than the lowest edge of the vehicle differential housing under maximum spring deflection, except that on cargo carrying vehicles with a gross vehicle weight rating of 6,000 lbs. or more, the lowest component may be at the lowest part of the vehicle body.

(o) Vehicle Weight Distribution. The total weight of the vehicle with the fuel containers filled to capacity shall not exceed the manufacturer's load rating for any axle, wheel, or tire.

1. Amendment of subsection (a) filed 8-15-77; designated effective 9-15-77 (Register 77, No. 34).
2. Amendment of subsection (a) filed 12-28-81; effective thirtieth day thereafter (Register 82, No. 1).
3. Amendment of subsection (b)(2)(A) filed 12-29-81; effective thirtieth day thereafter (Register 82, No. 1).
4. Change without regulatory effect of subsections (b) and (m)(4) filed 2-8-88; operative 3-9-88 (Register 88, No. 7).
5. Amendment of first paragraph filed 1-25-94; operative 2-24-94 (Register 94, No. 4).
6. Editorial correction of printing error in NOTE (Register 94, No. 4).

Note: Authority cited: Section 2402.6, Vehicle Code. Reference: Section 2402.6, Vehicle Code.

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