Resources Safety and Health Queensland (RSHQ) is investigating an explosion which took place at a chemical processing plant in Queensland.
Workers had just competed routine maintenance and were recommissioning equipment when pressurised hydrogen gas was released, resulting in an explosion and fire.
Three workers were injured, and the plant was damaged. Fortunately, the workers did not require hospitalisation.
Though the investigation into the September incident is in its infancy, the Regulator identified the failure of a high-pressure valve as the direct cause of the incident. The Regulator also indicated that the bearing bush bolts of the valve may not have been correctly installed at the time of overhaul, materially contributing to the incident.
In other words, the valve may not have been correctly reassembled after maintenance.
The Regulator emphasised the importance of checking correct assembly on high pressure valves following maintenance overhauls.
The Regulator also called for systems and processes that ensure quality assurance to be used for the overhaul and testing of these valves; and for the maintenance of the equipment involved in hydrogen usage to comply with original equipment manufacturer (OEM) specifications.
According to RSHQ, all site senior executives should:
- Remember that hydrogen is considerably more hazardous than liquid petroleum gas (LPG), as it possesses a wider explosives range, a lower ignition point, and is more difficult to contain
- Employ highly sensitive and specialised detection method, as detecting hydrogen gas leaks can present difficulties, particularly due to its tendency to disperse rapidly
- Refer to OEM specifications to ensure work methods and testing procedures are suitable for application, when working on a hydrogen equipment
- Ensure suitable trained personnel are engaged in maintenance and quality assurance.