The Australian Transport Safety Bureau (ATSB) issued the report of its investigation into a serious injury onboard the LNG carrier Northwest Stormpetrel at Dampier on 8 November 2014. The cargo engineer and an integrated rating were checking the LNG forcing vaporizer steam trap to resolve recurrent drainage issues.
The steam trap was isolated and depressurized so that a new gasket could be installed. Following gasket installation and reassembly, the system was checked prior to pressurization.
As the system was being pressurized, the valve’s bonnet came away, spraying steam on the cargo engineer and causing serious burns.
Investigation revealed that the bonnet locking clip (a small item that would have been located in a hard to see location) had not been installed, allowing the bonnet to unscrew.