A hydrogen leak occurred when hydrogen tube trailer traveling on a rural roadway left the road, overturned on its side, and resulted in a single hydrogen tube valve being opened or broken. The cause of the accident is unknown, however, it appears to be unrelated to hydrogen (i.e., it is likely that human driving errors caused the accident). The hydrogen tubes contained compressed hydrogen gas at 200 bar (2,900 psi). The back end of the tube trailer containing the high-pressure hydrogen plumbing and valves contacted the ground and resulted in the valve opening or breaking and losing all the hydrogen from one tube. The tube/valve that leaked was located on the bottom tier in the center position. The first firefighter crew to arrive at the accident scene verified that the leakage was limited to one tube/valve and that there was no overheating condition as verified by a thermal imaging device. The second firefighter crew (HAZMAT team),which was sent to recover the hydrogen remaining on the overturned tube trailer, determined that hydrogen recovery at the accident scene was not safe. The hydrogen tube trailer was lifted using lifting straps slung around the trailer near the hydrogen tube anchorage points, since the trailer did not have any fixed lifting points. After the tube trailer was righted, it was transported to the hydrogen supplier, where the hydrogen was removed and reclaimed. No injuries occurred related to the hydrogen leak.
- Vehicle & Fueling Systems
- Gaseous Hydrogen Delivery Vehicle
Increased structural protection is needed at the back of a hydrogen tube trailer to protect the vulnerable hydrogen systems components in this location (valves, pressure-indicating devices, manifolds, piping) in case of an accident. Side protection is especially important.
A system of designated lifting features is needed on hydrogen tube trailers to aid in accident recovery operations if the trailer is overturned or requires lifting. Typically, these types of accidents require the use of a crane for moving and lifting hydrogen tube trailers using lifting devices like slings. These lifting features should be designed to lift the hydrogen tube trailer with a full load of hydrogen cylinders and located at protected points. The current method for tube trailer lifting using slings around the hydrogen tube trailer at undefined locations and assumed centers of gravity is more hazardous and less safe.