Occupational Health & Safety Service

fire extinguishers - selection and use

Guidance on the selection of fire extinguishers.


The University Estates Office supplies fire estinguishers of various types to all the campus buildings. If you do not have the correct type of extinguishers available to you for the type of experimental work that you are undertaking please inform the University Safety Office so that your needs can be assessed and the correct type of equipment arranged.

There are several types of extinguisher available and they work in different ways. Basically they all interrupt the fire process by either removing heat from the fire (as in the case of a water extinguisher) or removing oxygen from the fire (as in the case of CO2), or both (as in the case of foam). They each have different advantages and problems.

Never attempt to tackle a fire unless you are confident that you can do so safely, ENSURE:
  • You have raised the alarm.
  • You are confident in your ability to operate the extinguisher.
  • You have the correct type of extinguisher.
  • You have a clear unobstructed route away from the fire in case it grows larger.

 

IF IN DOUBT - GET OUT, STAY OUT & CALL THE FIRE BRIGADE OUT!


The University Safety Office organises training course for staff who wish to learn how to operate a fire extinguisher correctly. Please contact the Office or go to the training pages for further information.

Types of extinguisher


The University have the following types of fire extinguisher in use.
  • Water
  • Foam
  • CO2
  • Dry Powder

The extinguishers will conform to one of two colour coding systems:

1.   If they are new they will be 'full-bodied' red with either coloured handles or a coloured label/band on the cylinder body.

2.   If they are older, the whole cylinder will be coloured with the indicator colour. 

The colours and uses are as in the table below.

Indicator colour
and Type

Best For

Dangers

Red
Water
  • Normal Solid Combustible Materials: Wood, Cloth, Paper, Plastics, etc.
  • Do not use on burning fat or oil
  • Do not use on fire involving electricity
Blue
Dry Powder

Multi-Purpose
  •  Flammable Liquids
  • Fire Involving Electrical Equipment
  • Do not use on chip or fat pan fires.
  • Fire may re-ignite.
  • Does not cool fire well.
Cream
AFFF

(Aqueous Film-Forming Foam)
  • Normal Solid Combustible Materials: Wood, Cloth, Paper, Plastics, etc.
  • Flammable Liquids
  • Do not use on burning fat or oil.
  • Do not use on fires involving electricity 
Black
Carbon Dioxide CO2
  • For fires involving electricity
  • Do not use on burning fat or oil.
  • The fire may reignite.
  • CO2 extinguishers can be harmful if used in confined spaces.
Red
Fire Blanket
  • When clothing catches fire.
  • and chip and fat pan fires
  • Solids - Wood, Cloth, Paper, Plastics, etc.
  • Flammable Solvents
  • If blanket does not completely cover the fire, it will not extinguish the fire.

Using Fire Extinguishers


The ways to use the different types of fire extinguishers are summarised as in the table below.

Please read the guidance on the labels of the fire extinguishers in your part of the building, and remember that staff are able to attend the University Safety Office arranged fire estinguisher training course.

Take the extinguisher to where you will use it.
Pull out the pin. (This will also snap the coloured plastic tag.)
Aim the hose or nosel.
Pull the trigger.


In the case of some old water extinguishers the procedure is different. For these you remove the top cover, aim the hose, and then strike the knob on the top of the cylinder.

Remember
Only use an extinguisher after raising the alarm.
Ensure you have a clear means of escape.
Use the correct type of extinguisher.

Type

How To Use

Works by

Red
Water
  •  Point the jet at the base of the flames.
  • Keep it moving across the area of the fire.
  • Ensure that all areas of the fire are out.
  •  Cooling
Blue
Dry Powder
  • Point the jet or discharge horn at the base of the flames.
  • With a rapid sweeping motion, drive the fire towards the far edge until all the flames are out.
  •   Smothering
Cream
AFFF and Foam
  •  Do not aim jet straight into the liquid.
  • Where the liquid on fire is in a container, point the jet at the inside edge of the container or on a nearby surface above the burning liquid.
  • Allow the foam to build up and flow across the liquid.
  • Smothering
Black
Carbon Dioxide CO2
  •  The discharge horn should be directed at the base of the flames.
  • Keep the jet moving across the area of the fire.
  • Do not hold the horn it gets very cold.
  • Smothering

 

Red
Fire Blanket
  •  If blanket does not completely cover the fire, it will not extinguish the fire.
  • Place carefully over the fire.
  • Keep your hands shielded from the fire.

 

  • Smothering