Suitable Extinguisher for the storage of cooking oils

[Tom Sutton]

I was posed this question recently and would like a second opinions.
 
"We are storing a reasonably large amount of cooking oil in 400L plastic tanks.  We have been thinking about fire fighting equipment and wondered if you might be able to give us some guidance.  We see that both powder and foam are listed for fats & oils, but would foam extinguishers be the most suitable, would you think?"

Cooking oil used in a deep fat fryer in an industrial kitchen no problem use a Wet Chemical Extinguisher. However stored in plastic containers in a warehouse and because the oil would not be contained I would think a dry powder would be more effective than foam? Another solution could be to bund the stack and used wet chemical or foam? I cannot think of any other suitable extinguishing procedure other than what is available to the FRS.

[kurnal]

I would think it very difficult to ignite bulk cooking oil from a typical small ignition source- its ignition temperature is above 340 deg C . A major fire may result from radiated heat or direct burning from a very large fire but that would already be way beyond the capability of first aid firefighting anyway.

Environmental pollution due to spillage would be the major hazard in my view, eg if a fork lift truck punctured a tank. I would look at stack size and spacing to limit the development and effects of  any catastrophic fire.

Like you I think dry powder may have the edge on quick knockdown of a small fire in the vicinity but foam spray would be much easier to clean up in the aftermath.  I would think the biggest hazard of a small fire in the vicinity would be a  leakage spillage of oil and the resulting mess, so absorbent and containment would feature in the emergency arrangements..

[AnthonyB]

Exactly as above - the cooking oil itself would only be involved as a secondary fire and would require a well established primary fire to become involved due to the high flash point and auto ignition temperature.

The oil would be a fire service problem to deal with, which would require most probably a continuous attack with aspirated foam in quantity - completely different from the 6 or 9 litres of non aspirated foam available in extinguishers, hence why fryers need wet chemical.

You should look at the types of primary ignition & fuel sources and provide an appropriate agent - CO2 for enclosed electrical ignition sources, foam or powder for mixed A/B fuels.

Powder - rapid knockdown, but no cooling (reignition risk), must totally extinguish liquids in one go or you get flashback, and of course obscures vision and makes a mess. No reignition potential. Works in all UK temperatures so can be placed in outside storage compounds

Foam - slower extinguishing, but cools, allows partial or progressive extinguishing of liquids, less mess. Foam blanket prevets reignition & can be used on spills to protect against a fire in the first place prior to clean up.Requires low freeze additive if kept outside in parts of the UK

The ultimate is to use the 'two by four' approach as per UK motorsport - powder for rapid knockdown then foam to cool & protect.

[Chris Houston]

Environmental pollution due to spillage would be the major hazard in my view, eg if a fork lift truck punctured a tank. I would look at stack size and spacing to limit the development and effects of  any catastrophic fire.

Good point, being on holiday at the moment, I'm too busy to look this up, but there was new legislation (promoted by the environment agency recently, I think) about the storage of bulk oil and the need for bunding and other protection.

[Ashley Wood]

Another option if the 'bund' route is chosen is high pressure water mist. This system is used in place of wet chemical in the food industry as it provides rapid knock down, high cooling effect and is clean. From a clean up aspect this would be better than foam or powder. The draw back would be cost as these systems are expensive.

[John Webb]

Is it possible for part of the warehouse to be set aside for this specific storage? Then you could bund the area and cover it with a water-mist system without having to go to the expense of covering the whole warehouse. It would also help separate the combustible liquid from other potential sources of fire and ignition.

[Tom Sutton]

Thank you all for your contributions I found them very useful.