June 11, 2015

Selection of Gaskets are important

During a process upset in a plant, a pressure transient took place. This led to two gaskets leaking in a pipeline carrying hazardous gases. Luckily the plant was shutdown and no untoward incident occurred. The investigation determined that improper gaskets were used.
1. Gasket failure
– A process shutdown lead to a transient pressure surge in the pipework which resulted in the failure of two gaskets, and a subsequent leak of hydrocarbons. The release activated the facility fire and gas
system, resulting in an emergency shutdown. Deluge was manually activated until the system had bled down and the release was confirmed to have ceased. There was no resultant fire or injuries.
2. Fuel line failure
– A fuel leak from a generator fuel line resulted in fuel being sprayed onto the generator exhaust resulting in a small pool fire. A Maintenance Engineer, working in an adjacent workshop, smelt
fuel and entered the generator room to investigate. He found a fuel oil mist around the generator and call ed the control room and notified of the leak. He then called for a ships generator to be put on line and left the generator room and shutdown the generator remotely. On his return to inspect the
engine, a small pool fire had started on the hot exhaust manifold covers. The fire was extinguished with a hand held extinguisher and there were no injuries.

What went wrong?
The incorrect installation of parts was a contributing factor in both incidents. Investigation of incident 1 found that a large number of installed gaskets did not meet the pipe specification. Two gaskets failed when exposed to an elevated pressure. Likewise for incident 2, the investigation found that incorrect hoses had been installed in a fuel supply service on the generator, which consequently leaked, resulting in a fire.

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