Liquified natural gas (LNG) is becoming increasingly popular as a clean and economic fuel. Road transport of LNG is now widely practiced.
Road tankers of LNG are not refrigerated – refrigeration to around -160 deg C is not technically or economically feasible for a road tank car. So an LNG road tank car will start to emit boil off gas. Since the tank cars are not pressure vessels the relief valve will lift and allow gas to vent after a period of time.
The tank cars are well insulated to minimise the rate of boil off. Vents are generally well positioned to disperse gas.
My specific concern involves the event where an LNG road tanker gets stopped for a prolonged period in a road tunnel. I can find no specific emergency procedures which address the specific risk which would arise if the road tanker vented of in a confined space.
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