During security testing conducted by the operator in the presence of the inspection of classified facilities, 2 shut-off valves did not operate at the tractor-trailer unloading station of an LPG depot. In the event of an anomaly, these positive safety valves enable the truck to be isolated from the other installations. The operator shut down the station until the installations could be refurbished. After verification, the problem was found to have been caused by the presence of a wasp nest that had been built inside the air system’s depressurisation solenoid valve, preventing it from operating. Additional checks, conducted on the site’s other solenoid valves of the same type, turned up additional nests in another device but did not prevent it from operating. The operator had mesh netting installed to prevent insects from entering the device.

Download the detailed report in .pdf format (843 Kb)