Piper Alpha

Introduction and commercial application Safety and the environment have become important elements of all parts of the field life cycle, and involve all of the technical and support functions in an oil company. The Piper Alpha disaster in the North Sea in 1988 has resulted in a major change in the approach to management of safety of world-wide oil and gas exploration and production activities. Companies recognise that good safety and environmental management make economic sense and are essential to guaranteeing long term presence in the industry. 

The UK government enquiry into the Piper Alpha disaster in the North Sea in 1988 has had a significant impact on working practices and equipment and has helped to improve offshore safety around the world. One result has been the development of a Safety Management System (SMS) which is a method of integrating work practices, and is a form of quality management system. Major oil companies have each developed their own specific SMS, to suit local environments and modes of operation, but the SMS typically addresses the following areas (recommended by the Cullen Enquiry into the Piper Alpha disaster) ... 

Ctillen. The Public Inquiry into The Piper Alpha Disaster (cmliiO)... 

In addition to these formal studies of human error in the CPI, almost all the major accident investigations in recent years, for example, Texas City, Piper Alpha, Phillips 66, Feyzin, Mexico City, have shown human error as a significant causal factors in design, operations, maintenance or the management of the process. Figures 4.4-1 and 4.4-2 show the effects of human error on nuclear plant operation. 

W. D. Cullen, The Public Inquity into the Piper Alpha Disaster, Her Majesty s Stationery Office, London, 1990, especially Paragraphs 6.109, 6.187, 11.3, and 18.29. 

Hjertager, B. H., T. Solberg, and J. E. Fprrisdahl. 1991b. Computer simulation of the Piper Alpha gas explosion accident. ... 

Competence assessment is also required if workers are assigned to new areas of work. In the offshore industry, considerable importance is being attached to the issue of demonstrating competence, following the recommendations of the inquiry that followed the Piper Alpha disaster. 

This case study concerns the events leading up to the hydrocarbon explosion which was the starting point for the Piper Alpha offshore disaster. It describes the investigation of the incident using the sequentially timed events plotting (STEP) technique. Based on the STEP work sheet developed, the critical events involved in the incident are identified and analyzed in order to identify their root causes. 

An initial explosion occurred on the production deck of the Piper Alpha Offshore Platform in the North Sea at about 1 00 PM on July 6,1988. The incident escalated into a tragedy that cost the lives of 165 of the 225 persons on the platform. Two additional fatalities occurred on a rescue boat. The Piper Alpha Platform was totally devastated. 

The case study has documented the investigation and root cause analysis process applied to the hydrocarbon explosion that initiated the Piper Alpha incident. The case study serves to illustrate the use of the STEP technique, which provides a clear graphical representation of the agents and events involved in the incident process. The case study also demonstrates the identification of the critical events in the sequence which significantly influenced the outcome of the incident. Finally the root causes of these critical events were determined. This allows the analyst to evaluate why they occurred and indicated areas to be addressed in developing effechve error reduchon strategies. 

Cullen, the Hon. Lord (1990). The Public Inquiry into the Piper Alpha Disaster. UK. Dept, of Energy. London Her Majesty s Stationery Office. 

Ever since the inception of the petroleum industry the level of fires, explosions and environmental pollution that have precipitated from it, has generally paralleled its growth. As the industry has grown so has the magnitude of its accidental events. Relatively recent events such as the Flixborough incident (1974), Occidental s Piper Alpha disaster (1988), and Exxon s Valdez oil spill (1989) have all amply demonstrated the extreme financial impact these accidents can produce. 

Smoke is a by-product of most fires caused by the incomplete oxidation of the fuel supply during the chemical process of combustion. It accounts for a large majority of fatalities of from fire incidents at both onshore and offshore petroleum facilities. In the Piper Alpha incident of 1988, probably the worst petroleum industry offshore life loss incident, the majority of deaths were not from bums, drowning or explosion impacts but from smoke and gas inhalation. The report on the incident concluded that, of the bodies recovered from the incident, 83% were as a result of inhalation of smoke and gas. Most of these victims were assembled in the accommodation awaiting evacuation directions or as they may have thought - a possible rescue. 

North Sea, Block 15/17, Piper Alpha, Explosion/Fire... 

The ESD system is distinguished from other facility safety systems in that it responds to a hazard situation which may affect the overall safety of the entire facility. It is therefore considered one of the prime safety systems that can be provided for any facility. Without an ESD system, an incident at a hydrocarbon facility may be provided with "unlimited" fuel supplies that can destroy the entire facility. Such situations are amply demonstrated by wellhead blowouts that can be fed from underground reservoirs and destruction of pipeline connections at offshore installations affecting the availability of further isolation means, eg., "Piper Alpha". 

Isolation - It has been shown that the addition of isolation valves at periodic intervals is not as cost effective as prevention measures such as thickness inspections or tests. However all pipelines should be provided with a means for emergency isolation at it entry or exit from a facility. Offshore facilities may be particularly vulnerable to pipeline incidents as the Piper Alpha disaster has shown. In that accident a contributing factor to the destruction was the backfeed of the contents of the gas pipeline to platform once the topside isolation valve or piping lost its integrity. Further isolation means (i.e., a subsea isolation valve SSIV) were not available. 

Speculations about the role of hydrates in disasters such as the Piper Alpha platform (Boniface, 1990) or Lake Nyos (Rogers and Yevi, 1996) are characterized as hypotheses that are not discussed in this book. 

Examples of major accidents that have happened in the industry are the Piper Alpha platform tire and explosion in 1988 that was caused by permit to work (PTW) system failure and layout issues where 165 people died the Bombay High platform, where in 2005 a multi service vessel (MSV) collided with the platform, causing riser damage and a fire that killed 22 people and the Texas City Refinery, where in 2005, maintenance and process start-up flaws caused a petroleum distillate to overflow, causing an explosion and a flash fire that killed 15 people. 

Piper Alpha, North Sea Release of hydrocarbons led to an explosion and destruction of the offshore platform. 165 deaths. 

If instmments are placed on manual, particularly emergency instruments, then a common cause event has been created. For example, one of the contributing factors in the Piper Alpha disaster was that both firewater pumps were on manual. They had been placed in that state to ensure that any divers in the water were not sucked into the firewater intake in the event of an automatic start of the pumps. Unfortunately, the fire on the platform prevented operators firom getting to the pumps to turn them on. The lack of firewater capability materially contributed to the magnitude of the disaster. 

On an offshore platform, however, the persons who are not on duty are still present, and they may be killed or injured. Many of the deaths on the Piper Alpha platform, for example, were of off-duty crew who were sleeping, and who could not escape from the Living Quarters. By contrast, 25 years later, when the explosion and fire occurred on the Deepwater Horizon platform, 11 men died instantly, but the other 135 persons on board survived the blast and subsequent fire. This is an indication that the safety measures that have been designed into platforms in the years following Piper have had a positive effect on safety improvement. 

The first safety cases prepared for the process industries were those developed for North Sea offshore oil and gas operations following the Piper Alpha disaster that occurred in the year 1988. The Cullen report (Cullen, 1990) that was written following that accident was highly critical of offshore operating practices and recommended that a safety case approach be implemented. The Seveso incident that occurred in Italy further prompted the increased use of safety cases. Since that time the use of safety cases has spread to other industries (such as mining and railway operations) and to other nations, primarily in Europe and Australasia. (It is notable that the safety case regime approach has not been taken up for offshore oil and gas operations in the Gulf of Mexico—instead a more prescriptive approach based on industry consensus standards is used.)... 

The stories we tell should have a resolution. In the case of major events such as Piper Alpha or Deepwater Horizon, the resolution could be new ways of managing safety (Safety Cases) or the introduction of new regulations (SEMS). Even less dramatic stories should always provide guidance to better behaviors or improved management systems. 

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