Safe Storage of Natural Gas on Urban Buses: Case Early Investigation and Learnings

The use of CNG in bus and private vehicles is growing steadily. Recent fire accidents involving CNG buses have shown that tanks may explode though compliant with current ECE UN R110 regulation. Such a repeated scenario is certainly not acceptable having in mind the tremendous amount of energy released when a compressed tank bursts. Investigation of German and French recent cases detailed in this article highlights potential improvements in current CNG buses fire safety concepts. Among others, it includes to rely on a system-level test and expectations in combination with the current component-level test. Fire safety should not solely rely on tank behaviour when exposed to fire but also to additional and upstream fire safety barriers. Thermal fuses can not be seen any more as an ultimate option to control tank burst in case of fire.