How Fire Extinguishers should be serviced

Professional fire extinguisher servicing and maintenance is an essential part of any fire protection system. It is the responsibility of a business owner or responsible person to arrange the regular service.

Stored Pressure Fire Extinguishers

Stored pressure fire extinguishers consist of a cylinder containing the extinguishing agent (water, powder, foam etc.) and are permanently pressurised with either dry air or oxygen-free nitrogen.

Basic Service (by a Qualified Engineer)

Fire extinguisher servicing should be carried out once a year to the standard laid down under BS 5306-3:2009. The service procedure involves thorough checking of the fire extinguisher for corrosion and partial or complete discharge. Reference should be made to the manufacturer's recommendations and instructions for specific information on servicing and recharging. Any fire extinguishers that are deemed unfit for use should be brought to the attention of the user and removed from service.

  1. Visually inspect the fire extinguisher for corrosion and damage.
  2. Check that the extinguisher has not been used, by checking the following:
    • Safety pin and tamper seal are in place (Fig. 1)
    • Pressure gauge reading (indicating needle should be in the green area (Fig. 2). This is not applicable for CO2 fire extinguishers)
  3. Check that the operating instructions on the extinguisher are clear and legible.
  4. Remove the discharge hose and check for blockages and corrosion (Fig. 3)
    • Once the discharge hose has been removed replace the ‘O’ ring.
  5. Weigh the extinguisher and record on the service label.
    • If there is more than a 10% weight loss, investigate and recharge.
  6. Wipe down the extinguisher.
  7. Ensure that the wall mountings are secure and in good condition before replacing the appliance back on the wall.

Extended Service (by a Qualified Engineer)

Every five years water, foam, powder and wet chemical extinguishers require a more detailed examination including a test discharge of the extinguisher and subsequent recharging.

Here is an overview of the main activities involved:

  1. Discharge the extinguisher
  2. Unscrew the headcap in a safe manner and check all removable parts for any sign of corrosion and blockages
  3. Examine the extinguisher body internally for any signs of corrosion
  4. Rinse water based extinguishers out with clean water
  5. Replace all 'O' rings and hose rings
  6. Refill the extinguisher
  7. Refit the headcap
  8. Re-pressurise the extinguisher
  9. After a refill with generic chemicals (not the original chemicals used by the manufacturer), the extinguisher must receive a label with the new chemical specification

The above only applies to pressurised extinguishers, only. Gas cartridge extinguisher servicing has not been described here.

Due to the amount of work to carry out the extended service, it is often cheaper to purchase a new extinguisher rather than carry out the extended service.

Cartridge Operated Extinguishers

Cartridge operated extinguisher are made up out of a cylinder filled with the extinguishant (water, foam, powder etc) and a gas cartridge containing highly pressurised CO2. The cylinder itself is not pressurised while not in use and the pressure is only released from the cartridge once the handle is squeezed and pierces the cartridge.

Basic Service (by a Qualified Engineer)

Fire extinguisher servicing should be carried out once a year to the standard laid down under BS 5306-3:2009. The service procedure involves thorough checking of the fire extinguisher for corrosion and partial or complete discharge. Reference should be made to the manufacturer's recommendations and instructions for specific information on servicing and recharging. Any fire extinguishers that are deemed unfit for use should be brought to the attention of the user and removed from service.

  1. Visually inspect the fire extinguisher for corrosion and damage.
  2. Check that the extinguisher has not been used, by checking that safety pin and tamper seal are in place
  3. Check that the operating instructions on the extinguisher are clear and legible
  4. Remove the discharge hose and check for blockages and corrosion
    • Once the discharge hose has been removed replace the "O" ring
  5. Remove the headcap of the extinguisher (slowly in case there is any pressure in the cylinder from a leaking cartridge)
  6. In the case of powder extinguisher, visually inspect the contents to ensure that it shows no signs of caking or clumping. If there is any evidence of caking then dispose of the contents and replace with new
  7. In the case of water based extinguishers, pour the contents into a calibrated bucket and inspect the inside of the cylinder with a torch, looking for any sign of corrosion or bubbling in the lining. Measure the contents using the bucket, if there is more than a 10% discrepancy then replace and investigate
  8. Remove the cartridge from the extinguisher headcap and inspect it. There are 7 pieces of information that should be marked on cartridges; manufacturers name, manufacture date, chemical sign of contents (i.e. CO2), nominal weight of charge, full weight, empty weight and the British Standard that the cartridge conforms to. If the extinguisher shows any signs of corrosion, does not display the 7 pieces of data, is over 10yrs old or has a discrepancy of more than 10% of the contents (i.e. 5.5g of a 55g cartridge) then replace with a new one
  9. Refill the extinguisher with the contents from the bucket, re-install the cartridge and replace the headcap onto the extinguisher (ensuring that you have replaced the headcap "O" ring with a new one first).
  10. Fill out the service label on the rear of the extinguisher
  11. Wipe down the extinguisher
  12. Ensure that the wall mountings are secure and in good condition before replacing the appliance back on the wall

Extended Service (by a Qualified Engineer)

Every five years water, foam, powder and wet chemical extinguishers require a more detailed examination including a test discharge of the extinguisher and subsequent recharging. All Extinguishers are recommended to be replaced every ten years.

Here is an overview of the main activities involved:

  1. Visually inspect the fire extinguisher for corrosion and damage
  2. Check that the extinguisher has not been used, by checking that safety pin and tamper seal are in place
  3. Check that the operating instructions on the extinguisher are clear and legible
  4. Remove the discharge hose and check for blockages and corrosion
    • Once the discharge hose has been removed replace the "O" ring.
  5. Remove the headcap of the extinguisher (slowly in case there is any pressure in the cylinder from a leaking cartridge)
  6. In the case of powder extinguisher, visually inspect the contents to ensure that it shows no signs of caking or clumping. If there is any evidence of caking then dispose of the contents and replace with new
  7. In the case of water based extinguishers, pour the contents into a calibrated bucket and inspect the inside of the cylinder with a torch, looking for any sign of corrosion or bubbling in the lining. Measure the contents using the bucket, if there is more than a 10% discrepancy then replace and investigate
  8. Remove the cartridge from the extinguisher headcap and inspect it. There are 7 pieces of information that should be marked on cartridges; manufacturers name, manufacture date, chemical sign of contents (i.e. CO2), nominal weight of charge, full weight, empty weight and the British Standard that the cartridge conforms to. If the extinguisher shows any signs of corrosion, does not display the 7 pieces of data, is over 10yrs old or has a discrepancy of more than 10% of the contents (i.e. 5.5g of a 55g cartridge) then replace with a new one
  9. Refill the extinguisher with the contents from the bucket, re-install the cartridge and replace the headcap onto the extinguisher (ensuring that you have replaced the headcap "O" ring with a new one first)
  10. Discharge the extinguisher safely
  11. Remove the discharge hose and check for blockages and corrosion
    • o Once the discharge hose has been removed replace the "O" ring
  12. Remove the headcap of the extinguisher (slowly in case there is any pressure remaining in the cylinder)
  13. Empty out any remaining extinguishant and dispose of safely. Swill out water based extinguishers with clean water
  14. Remove the cartridge from the extinguisher headcap and replace it with a new one (after inspection). There are 7 pieces of information that should be marked on cartridges; manufacturers name, manufacture date, chemical sign of contents (i.e. CO2), nominal weight of charge, full weight, empty weight and the British Standard that the cartridge conforms to. If the extinguisher shows any signs of corrosion, does not display the 7 pieces of data, is over 10yrs old or has a discrepancy of more than 10% of the contents (i.e. 5.5g of a 55g cartridge) then replace with a new one
  15. Refill the extinguisher with the correct quantity of extinguishant and replace the headcap onto the extinguisher (ensuring that you have replaced the headcap "O" ring with a new one first)
  16. Fill out the service label on the rear of the extinguisher
  17. Wipe down the extinguisher
  18. After a refill with generic chemicals (not the original chemicals used by the manufacturer), the extinguisher must receive a label with the new chemical specification
  19. Ensure that the wall mountings are secure and in good condition before replacing the appliance back on the wall

Due to the amount of work to carry out the extended service (especially with cartridge operated fire extinguishers), it is often cheaper to purchase a new extinguisher rather than carry out the extended service