Temporary Safe Refuge: An Oasis During a Lethal Crisis
Authors: Thirugnanam N , Sunil Mohamed , Adel Khalid , Al Awadhi Ibrahim 
Published: November 2017

Existing outdoor emergency assembly points in oil/gas plants were designed based on initial operations requirements. With several development phases and plants falling under high-sour facilities, current muster areas are unsuitable for safe evacuation of all employees during major accidents like large flammable/ toxic gas release, fire or blast. Lessons learnt from gas industries across the world reveal the necessity of providing Temporary Safe Refuge (TSR) for an endurance period till the situation is brought under control and facilities are evacuated safely.

In present condition where there are no guidelines/ specification for design of TSR, this paper addresses GASCO experience in developing sound technical specification, its details, implementation of same in providing Prefabricated Temporary Safe Refuge Shelters and carrying-out detailed study on cost-effective conversion of existing buildings to TSRs.

The process of introducing TSR concept in GASCO started with preparation of specifications that define in detail all systems, subsystems and general requirements. This includes Life support (oxygen for minimum 2 hours, gas & heat prevention), Structural support (leak proof envelope) and Command Support (communication to outside, emergency power & lighting, control on fire, smoke & gas) along with locations, configuration, escape support systems, acceptance criteria and other safety aspects.

In high risk areas where H2S concentration in process stream reaches upto 500,000 ppm, 2 Nos. Prefabricated TSRs were provided based on new specifications. It is an explosion-proof gas-tight construction with positive pressure inside and having all safety features including HVAC dampers, fresh-air supply, decontamination chamber, UPS and Gas detection/alarm systems.

Due to their high cost and need to refuge more personnel, it was decided to study the feasibility to convert some of existing buildings (MCR, IES, Fire-station, etc.) to TSR. Suitability of existing space, Electrical, Instrumentation, F&G systems, Fire-fighting and HVAC services to handle new design conditions were evaluated and concluded on the modifications to be carried out, without affecting the normal function of the buildings.

About 30 buildings were assessed individually for available spaces, functional criteria, safety systems, etc. to accommodate about 3000 people and recommendations were provided for conversion into TSRs. Fire, Blast and Toxic Gas Release scenarios were considered and all major mitigation measures proposed, such as: Fire and Gas detection/control, UPS, communications, Fireproof, air-tight, blast-resistant structure and enclosure, utilities and dry toilets.

Comparing the cost of Prefabricated TSR that accommodates lesser number of people, conversion of existing buildings to TSRs results very economical; hence, further engineering on the same was recommended.

"Detailed multi-disciplinary study" and "Specification for TSR" are exemplary tasks that are first of its 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 manpower, in a cost-effective manner.