7. Emergency Procedures

7.3. Fire Fighting

7.3.1 Exothermic reaction

If styrene vapour ignites and the temperature of the liquid reaches 52ºC, the stabilising effect of the inhibitor will be lost. There is then a serious risk that the liquid will auto-polymerise with the generation of considerable heat. Styrene tanks, which are heated by an external fire or other means pose a severe risk of bursting and explosion. See Appendix 2.

7.3.2 Fire Suppression

Fires involving styrene can be safely extinguished with foam, dry powder, water fog or carbon dioxide. However, water is not an effective extinguishing agent for use on water insoluble monomers such as styrene. Water jets should not be used, as these may simply spread the fire, styrene being both immiscible with water and lighter than water. Burning styrene may produce carbon, carbon monoxide, carbon dioxide and large quantities of thick black smoke. Fire fighters should wear breathing apparatus.

7.3.3 Foam

For extinguishing a fire and limiting evaporation, Aqueous Film Forming Foam or Alcohol Type Concentrate have been proven to be effective, i.e. that the lower flammability limit is not attained above the layer. Because a foam layer can break down, this function must be watched and maintained. As a few inches of foam are sufficient to smother a fire inside a container, the contained amount of water is unlikely to trigger a so-called slop over; larger amounts may do so.

If electrical equipment such as motors, open hot plates, or open electrical switches are involved, foam should be used with caution.

7.3.4. Water Spray

Styrene tanks or containers in the vicinity of a neighbouring fire should be kept cool by spraying with a water spray. Consider removing other flammable liquids in the vicinity.

A water spray has been proven to be the most effective way for product cooling, but its efficiency and effectiveness must be weighed against the risk of spreading styrene across the water surface, the chance of a slop over when water comes inside the tank, and the possibility to keep the product within a containment system. Because of its flammability and explosion hazard, styrene must be prevented from entering sewers. Also the control of the disposal of deluge and/or spray water is important because the contained styrene is an acute hazard both for public sewers and wastewater treatment plants. In case of such a release, Local Authorities must be informed immediately.

CEFIC
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Patrick Detournay
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E pdt@cefic.be