Working On CNG Or LPG Vehicles

What needs to be done before starting work on a compressed natural gas (CNG) or liquefied petroleum gas (LPG or propane) vehicle?

This question comes up from time to time and it may surprise you what is required. For any collision repairs, Honda for example requires the CNG tank be removed at a qualified dealership before the vehicle even enters the repair facility. Labels on the vehicle specify to not park the vehicle in an enclosed space after a collision. The labels say to have the vehicle inspected and repaired by a trained technician. And the labels specify to not use a spraybooth, which Honda refers to as a "paint oven," for any refinishing repairs.

One of the requirements for a qualified CNG facility, as stated in National Fire Protection Association or NFPA code 52, is an approved flammable gas detection system calibrated to the specific gas. In the event of a gas leak, the gas detection system must emit an audible and visual alarm, automatically open vents to the outside, and automatically shut off the facility heating system.

In the case of a qualified LPG facility, the same fire code requirements apply to LPG as CNG. The repair facility must be equipped with an approved flammable gas detection system calibrated to LPG, which in this case must detect vapors hovering at floor level. The fact that the pressure relief valve can open so easily makes it especially critical for the tank to be removed before any collision repairs.

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