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Mongstad: Dangerously near

The steam leak at the Mongstad refinery in November had a clear major accident potential. It is viewed as serious by the PSA, which aims to get to the bottom of what happened.




This article was originally published in
Safety - Status and Signals 2012-2013

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The accident at the facility north of Bergen occurred in the cracker, with the fracturing of a blowdown pipeline for feed water at a temperature of 245°C.

Large volumes of steam escaped under high pressure, and the leak rate is estimated to have been about 78 kilograms per second.

Scaffolding
Nobody was present when the break happened, but scaffolding had been erected
close to the site the day before  and a team had been due to start work there a few hours after the accident.

The conclusion is that, had the leak occurred at a different time, several people could have been very seriously injured and – in the worst case – lost their lives.

Corrosion under the insulation was the cause of the fracture. This type of deterioration is a defined problem in the industry, and all the land-based plants have programmes for following it up.

Noise
In addition to the steam pouring from the broken pipe, noise in the area around the cracker was so loud that communication with the control room became impossible. That made dealing with the incident particularly demanding, but a quick-thinking plant operator who spotted the accident cycled to a spot where he could talk with the control room.

He then biked backwards and forwards with messages, until it proved possible to halt the leak with the aid of a shut-off valve after about 12 minutes.

The PSA’s investigation into the incident is not finished.