STRAP BLASTSTRAP FROM
THE PAST
The remains of the Piper Alpha Oil rig burn following the explosions and fire that destroyed most of the platform on 6 July 1988. (Inset: Piper Alpha before the incident.)
PIPER ALPHA OIL PLATFORM DISASTER—1988 BY
BARRY LEE OAM
O
perated by Occidental Petroleum, the Piper Alpha offshore oil platform was located in the North Sea about 270 km north-east of Aberdeen, Scotland. It stood on a 150-metre high steel jacket weighing 14,000 tonnes, which was piled into the sea bed. A frame on top of the jacket supported decks packed with process and production equipment, pumps, compressors and living quarters. Overall, the platform consisted of 34,000 t of steel, measured 241 m from the bottom of the deepest pile to the highest point and accommodated 36 oil wells. Subsea pipelines carrying oil and gas radiated out from Piper Alpha, linking it to the Claymore, Tartan and MCP-01 platforms and to the Flotta oil terminal in the Orkney Islands. On 6 July 1988, work began on one of two condensate injection pumps used to
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compress gas prior to transport to Flotta. A pressure safety valve was removed for recalibration and two blind flanges were installed in the open pipework. The dayshift crew then finished work for the day. That evening the other pump tripped and the nightshift crew unwittingly started the ‘out of service’ pump. Condensate leaked from the two blind flanges. Around 10.00 pm the leaking gas ignited and exploded, causing fires and damage to other areas with further release of gas and oil. About 20 minutes later, the Tartan gas riser failed and a second major explosion occurred, followed by widespread fire. Fifty minutes later, the MCP-01 gas riser also failed, resulting in a third major explosion. More explosions followed with extensive collapse of a significant proportion of the installation. The other rigs feeding into the same oil export line did not shut down until one hour after the initial mayday, which meant that oil from the other rigs flowed back
towards Piper Alpha and continued to fuel the fire. At the height of the blaze flames could be seen 100 km away. Routes to the lifeboats were blocked. Helicopter operations were hampered by the heat and smoke. As a result of the explosion and the fire on Piper Alpha, 167 men died. Sixty-two men survived, mostly by jumping into the sea from the high decks of the platform. Damage was estimated at US$1.4 billion and at the time it was the worst disaster in the offshore oil industry. The subsequent inquiry presented 106 recommendations for changes to North Sea safety procedures.
CLOSER TO HOME…
The Marlin platform in Bass Strait, 50 km south-east of Lakes Entrance, Victoria, which had previously sustained a gas blowout in 1968, was involved in a serious fire in 1971. At the time, 32 men were working on the platform. Most jumped into the sea and were rescued by helicopter.