The Piper Alpha Explosion & 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 enquiry 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 nuclear,
airline, military and other sectors.
The BBC made a documentary programme analysing the events which occurred
on that fateful night which 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 from 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 crucial 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
physical dangers were located away from the personnel area. But
this safety precaution was abandoned when gas production began
and a propane condensate pump was located near the control room.
This modification later proved to be a fatal error in the design
of the platform.
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
anyone 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. Almost immediately
the gas caught fire 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 come on automatically, but it was switched to manual
control because divers in the sea would be in danger of being
sucked into the water inlets if the system was 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 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 not
able to land on this and rescue the men due to the fire, smoke
and wind.
The fire did continued to blaze because oil and gas was 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 reached 300ft
into the air. It was only after this explosion that Claymore
finally 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 of the rig, came loose and fell into the sea.
Soon most of the remainder of the platform also slipped beneath
the waves.
A total of 167 people lost their lives in the Piper Alpha
disaster from 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. A total
of 106 safety recommendations were made in the inquiry's report.
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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