Indianapolis gas cylinder explosion: CNG flies 1,2 kilometer - lands in school yard
Vehicles powered by natural gas poses different risks and dangers during a fire than gasoline powered vehicles. In 2015, the Indianapolis Fire Department in the US responded to an incident where the CND tanks exploded.
One cylinder was thrown 1,2 kilometers from the explosion site, landing in a school yard.
Against normal procedure for fires involving in such vehicles, the driver was unable to “dump” the burning debris. This resulted in a the heat build- up directly under the cylinders.
A contributing factor was a protective cover over the tanks. The cover likely hindered cooling the tanks and may have inadvertently caused the pressure reducing devices ( PRD ) to be cooled by the water stream and prevented their activation.
It is speculated the water spray applied may have kept the PRDs below their intended trigger temperature.
From a tactical perspective, if a vehicle is known to be equipped with CNG cylinders and is well involved with fire, firefighters should maintain a safe perimeter and not approach the vehicle, unless there is a significant life hazard , i.e. let the vehicle burn.
A minimum evacuation radius of 300 feet (90 meters) should be maintained in such incident types.
As experienced in this event, a tank landed approximately 4,000 feet (1,200 meters) away.
Do not approach from either the front or the side of the vehicle. If necessary, approach a CNG vehicle fire from a 45° angle.
If the PRD(s) have activated, do not apply water spray, but rather allow the fire to burn.