Piper Alpha oil installation fire and explosion
The Piper Alpha oil platform explosion (July 6th, 1988) was one of the most expensive manmade catastrophes ever experienced worldwide, and the worst disaster on an offshore oil platform in terms of impact on the industry and lives lost! 167 people died, with 30 bodies never accounted for and the final loss totalling £1.7bn. The disaster subsequently led to the Cullen Inquiry, chaired by William Cullen, and the following Public Inquiry into the Piper Alpha Disaster
report. This included 106 recommendations to be made to safety procedures for oil platforms on the North Sea, and proved critical about Piper Alpha’s operator Occidental, although no criminal charges were ever brought against them.
Piper Alpha opened in 1976 as an oil-only platform, and was destroyed 12 years later by the explosion and subsequent fire. By this point it had been converted to include gas production and was one of the three heaviest platforms in operation on the North Sea.
The platform had been designed with safety in mind and as such personnel areas were kept furthest away from the areas where the most dangerous work took place. When the platform was converted to also include gas production, these safety features were compromised – the fact the gas compression area was placed right next to the control room was contributory to the amount of lives lost, as the control room was deserted after the initial blast due to safety and could not be used to form an evacuation plan. In addition, many key personnel died in this room, meaning they were not able to coordinate evacuation efforts.
As the platform was destroyed and many on the platform died, the official timeline and chain of events is theoretical, based on known facts.
The platform was operating as normal on July 6th, 1988 – that morning, a pressure safety valve on Pump A had been removed for maintenance. Due to delays, the maintenance work could not be completed that day and as such the open condensate pipe was temporarily sealed and a permit completed and signed by the on-duty engineer stating the pump should not be used or switched on under any circumstances! Unfortunately, due to miscommunications between the engineer and overnight custodian, this permit was not handed over correctly and the custodian was not aware of the condition of Pump A.
Later in the evening, Pump B started to malfunction due to issues with the methanol system. Pump B then stopped and would not restart. As this would then leave the platform with no power with Pump A also offline, engineers decided to turn Pump A back on, as they could not find (and were not aware of) the Permit relating to the condition of the pump, nor the missing valve.
Pump A was turned back on at roughly 9:55PM, leading to the first explosion as gas entered the pump. The metal plate that had been loosely fitted to cover the missing valve could not withstand the pressure and gas began to leak out of the pipework. The leak was loud and heard by men nearby; six gas alarms were also triggered, however the gas ignited and exploded. The emergency stop button was pressed which stopped all oil and gas extraction but the firewall had blown and the fire was not contained. Another fire was then ignited by blown panels tearing through a smaller condensate pipe.
The fire quickly spread and “Mayday” was signalled for aid from the mainland – the control room was then deserted and any type of organisation that could have come together to form an evacuation was lost. It was impossible to reach the lifeboat stations due to the fire, so the only option was to move to the fireproofed living quarters and await further instructions, which never came. Helicopter rescue teams could not land due to the adverse conditions on the platform. By 10:05PM rescue teams were frantically trying to reach the personnel stuck on the platform, however, further disaster struck at 10:20PM when the Tartan Gas Line which fed into Piper Alpha ruptured, shortly followed by the Claymore Gas Line at 11:18PM.
Neither the Tartan nor Claymore lines had been turned off after the first explosion so were feeding the original fire with oil. It is said that this was partly due to the cost of such a shutdown, although Occidental management were aware of how devastating rupture and explosion of these lines would be.
Firefighting rig Tharos, which pumped 40,000 gallons of water onto the platform every minute, suffered melted paintwork from half a mile away. Helicopters couldn’t get any closer than a mile away due to the heat, and the water was so hot that men who had jumped in to escape the flames saw their plastic hard hats melting.
By 11:50PM, a number of people had been rescued by helicopter and standby vessels, but at this point the platform started to collapse as critical parts of the support structure had burned away. The crewmen still sheltering in the living quarters sank into the sea. From here on out, “Rescue 138”, a No. 202 Sqn Sea King helicopter from RAF Lossiemouth rescued as many remaining personnel as possible but by 00:45AM the whole platform had gone. Out of the 226 people on the platform that evening, 61 survived.
It took three weeks to fully extinguish the remains of the platform. Later that year, the bodies of 87 men were recovered and laid to rest when the remains of the platform that contained the living quarters was winched from the sea bed.
Aftershock & Cullen Inquiry
The immediate aftermath of the disaster was one of horror – the relatively short time between the initial explosion and the total collapse of the platform was likened in recent years to that of 9/11, such was the utter devastation and speed that events overcame those on the platform and aiding in the rescue. Two crew members from a nearby vessel also died.
In November 1988, the Cullen Inquiry was established to ascertain the causes of the disaster and present recommendations to safety to prevent such an event happening again. The Cullen Report was released in November 1990, more than 2 years after the disaster, which contained 106 recommendations; 37 relating to operating equipment, 32 relating to platform personnel, 25 relating to the design of platforms in the future and 12 relating to the emergency services. The Offshore Installations (Safety Case) Regulations 1992 were then adopted following the Cullen Report.
From a financial perspective, the explosion led to insurance claims that totalled around $1.4bn – a huge amount which at the time made it the largest insured man-made disaster in the world. Occidental, the platform operator, paid out millions in compensation to the families of the deceased and survivors. However, they did go onto sue 26 contractor companies for the compensation pay-outs as a recoupment exercise in 1992.
Offshore Installations (Safety Case) Regulations 1992
The Offshore Installations (Safety Case) Regulations are free to download from the HSE website, although have since been amended in 2005 to make the process of submitting a Safety Case less complex.
They exist to reduce and prevent risks to those working on offshore platforms and ensure that every operator/owner for each offshore installation prepares and submits a safety case to the HSE – this was Lord Cullen’s central recommendation in the Cullen Inquiry. A Safety Case is prepared to ensure there are the ability and means to control a major accident should it occur, although these Regulations do not set the standards by which the Safety Case must adhere to – these are set by PFEER, DCR, HSW and other safety regulations.