The LWF Blog

Facilities Management & Fire Safety – Fire Extinguishing Equipment – Part 3

January 19, 2017 4:23 pm

In this blog series for those who work in Facilities Management and who have a responsibility for or interest in Fire Safety, we are currently looking at Fire Extinguishing Equipment. Being able to recognise each type of fire extinguisher is important, as well as understanding how they can be used to assist with extinguishing a fire in its early stages.


There are four main types of fire extinguisher – water, foam, powder and carbon dioxide. These are most likely to be found in general use and we will look at each type in the course of the next few blogs.


A water extinguisher is the type most commonly seen in workplaces and public places. It is suitable for use on Class A fires, which are those fires involving normal combustibles such as wood, textiles, paper etc. A water extinguisher helps to extinguish a fire by cooling the fuel – which in this case is the combustible materials named – by soaking it in water.


A water extinguisher should not be used on Class B fires, which are those fires involving flammable liquids and nor should it be discharged onto electrical equipment.


As many of these extinguishers contain 9 litres of water, they are quite heavy for many people, coming in at around 13kg.  A 9 litre extinguisher of water will provide a discharge for around a minute and the water will jet approximately 6m from the source.


The method of discharge varies depending upon the type of release mechanism fitted within the extinguisher. It can be from the release of permanently stored pressure, from the generation of pressure, on operation of the extinguisher or due to the release of gas from an internal gas cartridge. All of these methods will work automatically when the fire extinguisher is made operational, so the user will not need to trigger the extinguisher any differently.


It is possible to use a fire extinguisher with the same fire rating as a 9 litre extinguisher, but for it be smaller and lighter. The addition of a wetting agent as an additive can make a difference to the size and weight without losing fire rating. These extinguishers would typically contain 6 litres of water, but while they are potentially useful in situations where smaller or less physically-strong members of staff might find it hard to handle a 9 litre extinguisher, they also have a faster discharge time which can make them less effective in the hands of untrained staff.


In next week’s blog, we will be looking at foam extinguishers – what types there are and how they should be used in a fire situation. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact Peter Gyere in the first instance on 0208 668 8663.


Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 25 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings



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