Existing outdoor emergency assembly points in oil and gas plants were designed on the basis of initial operational requirements. With several development phases and plants falling under the designation of high-sour facilities, current muster areas are unsuitable for the safe evacuation of all employees during major accidents such as large flammable or toxic gas releases, fires, or blasts. Lessons learned from gas industries across the world reveal the necessity of providing temporary safe refuges (TSRs) until the situation is brought under control and facilities are evacuated safely.
This paper presents one company’s experience developing sound technical specifications for prefabricated temporary safe refuges (TSRs). It also details the specifications and presents their implementation and the detailed studies conducted on cost-effective conversions of existing buildings to TSRs.
The process of introducing the TSR concept in the company started with preparation of specifications that define in detail all systems, subsystems, and general requirements. This includes life support (oxygen for a minimum of 2 hours and gas and heat prevention), structural support (a leak-proof envelope), and command support (communication to outside; emergency power and lighting; and control on fire, smoke, and gas) along with locations, configuration, escape support systems, acceptance criteria, and other safety aspects.
In high-risk areas where hydrogen sulfide concentrations in the process stream can reach 500,000 ppm, two prefabricated TSRs were provided on the basis of new specifications. They are of explosion-proof gas-tight construction with positive pressure inside and include all safety features, including heating, ventilation, and air conditioning (HVAC) dampers; fresh-air supply; decontamination chamber; and gas detection and alarm systems.
Because of their high cost and the need to refuge more personnel, a decision was made to study the feasibility of converting some of existing buildings to TSRs. The suitability of the existing space and electrical, instrumentation, fire-fighting, and HVAC services to handle new design conditions were evaluated, and a conclusion was made that the modifications could be carried out without affecting the normal function of the buildings.
Approximately 30 buildings were assessed for available space, functional criteria, and safety systems to accommodate approximately 3000 people, and recommendations were provided for conversion into TSRs. Fire, blast, and toxic-gas-release scenarios were considered, and all major mitigation measures were proposed.
Considering the cost of a prefabricated TSR that accommodates fewer people, the conversion of existing buildings to TSRs is economical; hence, further engineering was recommended.
A detailed multidisciplinary study and specifications for TSRs were first of their kind in this region in protecting people during hazardous events. The findings and mitigation measures will provide ample guidance and knowledge to industry in providing emergency safe refuge to workers in a cost-effective manner.
Find paper SPE 188551 on the HSE Technical Discipline Page free for a limited time.