Natural gas is a lighter-than-air fuel that is a gas at atmospheric conditions. The unique properties of natural gas need to be taken into account in any new or existing garages or facilities where compressed (CNG) and liquefied (LNG) natural gas vehicles are to be maintained, loaded or stored.
Canada now has a Technical Guideline to help fleets and vehicle dealers determine what modifications may be required to make their facilities gas-safe.
Natural gas is lighter than air.
Natural gas will rise and disperse quickly in the event of a leak. This property has implications for facility ventilation as well as roof and ceiling design. Facilities need to be assessed to determine and address whether there are any “pockets” that could trap natural gas if a leak occurred.
Natural gas has a narrow flammability range.
Natural gas will only combust if the mixture of gas in the air is between 5% and 15%. Below 5%, the mixture is too lean and it will not burn. Above 15%, the mixtures is too rich and it will not burn. Facilities used for natural gas vehicles require ventilation systems that can quickly and automatically remove the risk in the event of a leak.
Natural gas must be at a higher temperature to ignite compared to liquid fuels.
The ignition temperature for natural gas is approximately 900-1200 degrees Fahrenheit. By comparison, diesel has an ignition temperature of less than 500 degrees Fahrenheit. The relatively high ignition temperature of natural gas allows for a higher surface temperature limit for equipment that could come into contact with natural gas if a leak occurred.
The Technical Guideline addresses facility requirements for CNG and LNG vehicle maintenance, loading, and storage. It is intended to serve as a reference document for facility design and operational issues. Fleets and vehicle dealers can take the Guideline to their local engineering or architectural firm to conduct an assessment and determine what modifications are needed to ensure that their facilities are safe to use for CNG and LNG vehicle maintenance, loading, and storage.
Note that this Guideline is not intended to apply to occasional parking of light duty vehicles in public or private parking garages.