Case Studies - Assessment & Control of Risks from Chemical Warehouse Fires

One of the responsibilities of HSE is assessing and controlling the risks from major industrial accidents through the Control of Major Hazards (COMAH) Regulations. One important example of such a risk is fire in warehouses that store large quantities of toxic materials. Based on risk assessments of the potential consequences of these incidents for people living in the vicinity of such warehouses, HSE gives advice on land use planning and judges the adequacy of the information set down in safety reports.

Since the early 1990s HSE has undertaken a programme of development of its methods in this area. The first strand of this process has been the development by HSL of a computer model (FIREPEST). This software allows rapid, accurate and consistent assessments based on existing information on fire growth, combustion chemistry, building response and fire plume dispersion.

The second strand of HSE's development programme has involved the sponsoring of research in some of the key areas of uncertainty. Examples of such areas have included:

• fire growth in chemical commodities;
• combustion chemistry and the nature of fire plumes;
• dispersion of buoyant releases from warehouse buildings;
• behaviour of aerosols in fires;
• building response to fire; and
• mitigation of chemical fires.

Experimental research at HSL on mitigation of fires in agrochemical stores has examined the effectiveness of commonly installed automatic suppression systems. Other means of reducing risks have also been studied including: fire partitioning, use of fusible skylights and frangible roofing materials, fire resistant packaging and stock reorganisation.

An important part of this work involved large scale testing of the sprinkler systems used to protect stocks of flammable pesticide products in plastic bottles. Tests of this sort had not previously been carried out. The results clearly demonstrated that current sprinkler installation standards are inappropriate for many agrochemical warehouses and that further controls are necessary to achieve an acceptable level of fire safety.

  Back to the top