Alert over Buncefield gauges
21 Sep 2006
The Health & Safety Executive has issued an urgent safety 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.
The gauge switches manufactured and supplied by Cynergy3 Components Ltd of Winborne, Dorset, are being looked at as a possible factor in the Buncefield incident, according to a HSE spokeswoman.
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.
Meanwhile, Cynergy3 is trying to contact operators that fit its TAV level gauges to their storage tanks. Around 2000 of the units have been sold worldwide, including products from the firm's predecessor companies Crydom Magnetics Ltd, TAV Engineering.
The Dorset-based firm did not reply to requests for comment about the alert.
Cynergy3, part of Cynergy3 Corp. of San Diego, has, meanwhile, provided revised instructions and labeling on the safe use, setting, cleaning and maintenance of the switches. "We are now looking to see if these new instructions are clear and ensure that the problem will not be repeated," the HSE official said 8 Sept.
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.
Failure of the system to trigger may have allowed a major oil storage tank to overflow, leading to a massive vapour cloud that ignited to devastate the Buncefield site.
The gauges are 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.
"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 HSE.
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.
