Buncefield: Alert over Dorset firm's level gauges

London – The Health & Safety Executive has issued an urgent alert to operators of oil/fuel storage facilities that employ tank level gauges similar to those in use at Buncefield at the time of the explosion there last December.

Operators in the UK, Europe, the US and Canada, are being advised to check where TAV level switches manufactured and supplied by Cynergy3 Components Ltd of Wimborne, Dorset, are fitted to their storage tanks. The alert, which also covers products from the firm’s predecessor companies Crydom Magnetics Ltd, TAV Engineering, has so far been received by 108 companies, said a HSE spokesman.

Cynergy3, which is part of Cynergy3 Corp. of San Diego, California, is to provide revised instructions and labelling on the safe use, setting, cleaning and maintenance of the switches, according to the latest official Buncefield report, issued 13 July.

Cynergy3 was established in March following the sale of Crydom’s solid-state relay product line to Schneider Electric. Cynergy3’s portfolio encompasses power semiconductors, power modules, high-voltage reed relays as well as liquid level / flow sensors. A spokeswoman at the Dorset-based firm was unable to comment on the HSE alert.

Operators are being told to check TAV level switches fitted with change over reed switches, which are normally used in de-energised mode to maintain alarm/trip circuits in normal status.

The units can be tested by raising a lever or plate fitted to the switch head to simulate a high level in the tank. If the device is working properly, this action will trigger alarms and trips connected to the switch. The HSE stressed that the switch can be inoperative if the lever/plate is not returned to the correct position and locked in place after this test.

Investigators are still trying to determine how the gauging system performed prior to the explosion and why automatic shutdown of delivery did not take place as intended when the tank’s maximum capacity was reached.

“The design of the ultimate high-level switch indicated that the position of a test lever or plate fitted to the switch is critical to ensure continued effective operation,” according to the initial Buncefield report.

“While the relevance of this feature to the Buncefield incident has still to be determined, one of the issues that has arisen from these enquiries relates to the reliance on this type of switch at many similar installations throughout the UK and worldwide,” the report stated.