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LEARNING FROM MAJOR DISASTERS   


The Piper Alpha Explosion and Fire

  
 
 

Introduction  

The world's worst offshore disaster claimed 167 lives when an explosion and fire occurred on the Piper Alpha platform in the North Sea in 1988. The subsequent inquiry made 106 safety improvement recommendations.
 
Lessons learned from the disaster have been used across the world to improve safety, not only in the oil industry but also in the nuclear, airline, military and other industries. 
 
The BBC made a documentary programme analysing the events which occurred that night and this is available as a safety training DVD called "Spiral to Disaster".
 

 

Background

A joint venture of four companies obtained a licence in 1972 to explore for oil and gas under the North Sea. In early 1973 they discovered what was to become known as the Piper Field, approximately 120 miles north-east of Aberdeen.
 
An oil terminal was built at Flotta in the Orkney Islands to receive oil by a 30-inch diameter undersea pipeline from the Piper Alpha platform and the Claymore and Tartan platforms. Oil production began in 1976, and gas production in 1980. The links carrying oil and gas between these locations became critical factors in the subsequent disaster.

   
 

The Piper Alpha Platform

The Piper Alpha platform was fabricated in sections by McDermott Engineering of Ardersier and UIE of Cherbourg.  The two parts were amalgamated at Ardersier before the platform was towed to its location in 474 feet of water in 1975.
 
An important aspect of the design of the oil platform was that dangerous operations which could result in fire, explosion or other physical dangers were located away from the personnel area. However, this safety precaution was abandoned when gas production began, and a propane condensate pump was located near the control room. This modification to the design of the platform later proved to be a fatal error.
 
Piper Alpha was operated by Occidental Petroleum (Caledonia) Ltd, known as "OpCal". At the time of the disaster Piper Alpha handled approximately 10% of the total oil and gas output from the North Sea.
 

 

Explosion and Fire

The pressure safety valve of Condensate Pump "A" was removed for routine maintenance, a blanking piece was put in its place and the necessary paperwork stating that the pump should not be switched on was completed. Unfortunately, the unavailability of the pump was not drawn to the attention of personnel in the control room.

 

Pump "B" failed and the staff in the control room searched for paperwork regarding the state of Pump "A" and its safety valve. None was found and Pump "A" was started. 

 

On 6th July 1988 the temporary blanking plate failed and a high pressure gas leak occurred. The gas caught fire almost immediately and there was a huge explosion. The blast damaged another pipe, causing a second fire.

   
 

The Growing Disaster

Piper Alpha was equipped with a fire control system. Normally, this would activate automatically, but it had been switched to 'manual control' because divers in the sea would have been in danger of being sucked into the water inlets if the system started. However, the fire system's manual control was in the control room that was near the heart of the explosion and which had been evacuated.
 
Lifeboat stations were provided on the platform and the safety instructions directed the men to them in an emergency. However, they found their way barred by fire, so instead made their way to the fireproofed accommodation block. Rescue helicopters were unable to land on this and rescue the men due to the fire, smoke and wind.
 
The fire continued to blaze because oil and gas were still being pumped to Piper Alpha from Claymore and Tartan, despite emergency calls made to these locations.
 
   
 

Spiralling Out Of Control

A gas pipe from Tartan ruptured, resulting in a further explosion and a fire that reached 450 feet into the air.

Another pipeline ruptured and exploded. The fire from the pipeline reached 300ft into the air. It was only after this explosion that Claymore ceased pumping oil to Piper Alpha.
 
The heat began to soften the steel and affect the structural integrity of the platform, with catastrophic results. The fireproof accommodation block, containing most of the men who had not jumped off the rig, came loose and fell into the sea. Soon most of the remainder of the platform also slipped beneath the waves.
 
The causes of the 167 fatalities were suffocation by toxic fumes, by fire and through drowning. A memorial sculpture to the victims by Sue Jane Tyller stands in the Rose Garden of Hazlehead Park in Aberdeen.

 

 

A Public Inquiry

Lord Cullen chaired a public inquiry into the events that led to the destruction of Piper Alpha and consequent loss of life. The 106 safety recommendations in the inquiry's report comprised 37 relating to the procedures for operating the equipment, 32 connected with the relaying of information to the platform personnel, 25 concerning the design of the platform and 12 involving the provision of timely information to the emergency services.

 

 

Safety Training Material

NEBOSH training includes the BBC's "Spiral to Disaster" DVD about the Piper Alpha tragedy. Details can be found here.

 

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