18Aug 2011
by Nick Potter

Water Fire Extinguishers

Water Fire Extinguishers

Water Fire Extinguishers are the most common extinguisher medium.  They have limitations in their use as they are only suitable for Class A materials when used as an extinguishant.  Class A materials are flammable solids, which include wood and paper.  Class A materials are by far the most common fuel source, hence the popularity of the water fire extinguishers as an extinguishant medium.  Water Fire Extinguishers achieve extinction of a fire by cooling.

Water Fire Extinguishers

Advantages of Water Fire Extinguishers

  • Good Absorbance of Heat
  • Cheap
  • Readily Available
  • Range of Jet
  • Striking Power of Jet

Disadvantages of Water Fire Extinguishers

  • Conductor of Electricity
  • Not Suitable for Flammable Liquids
  • Not Suitable for Flammable Gases
  • Not Suitable for Flammable Metals
  • Not Suitable for Cooking Oil Fires

Operation of Water Fire Extinguishers with a CO2 Gas Cartridge

Water Fire Extinguishers use a mechanical action to release the water from the cannister.  This is achieved by using a cartidge containing an inert gas (usually) CO2.  When the gas is released from the cartridge it expels the extinguishing agent from the extinguisher. 
This occurs via the following method:-

  1. On operation of the water fire extinguishers
  2. A cartridge is pierced
  3. CO2 gas is released through gassing ports into the top of the extinguisher
  4. The gas forces down the water
  5. Up the syphon tube
  6. Through the headcap and hose onto the fire

N.B.  Some water fire extinguishers feature a squeeze grip control at the end of the hose.

Water Fire Extinguishers Cartridge Operated Safety Guidance Notes

  • Before opening water fire extinguishers, any vent holes or devices should be checked.  The unit should then be opened slowly to allow any release of pressure.
  • A periodic discharge test should only be carried out after a check for corrosion has taken place.  Corroded water fire extinguishers bodies could burst injuring the operator.
  • If the safety pin and seal is missing, ensure it is in good working order before fitting a new pin and seal.
  • If water fire extinguishers are condemned and it is not possible to get authorisation for replacements, ensure that the extinguisher and the service records are marked accordingly.  Remove from situ and make safe.

For More Information On These Products Please Click The Following Link:- Water Fire Extinguishers