Offices are full of laptops, computers, printers, mobiles, electrical cupboards, power adaptors, batteries and other electrical equipment which can become faulty or overheat. While an electrical fire will often trigger the fuse to be blown, any extinguisher used should be safe for use on live electrical equipment in case it is not possible to unplug or switch off the supply to the burning equipment.
CO2 fire extinguishers discharge a 10-15 second burst of carbon dioxide (CO2) which suffocates the fire. The CO2 starves the fire of oxygen and extinguishes it. The disadvantage is that the gas dissipates and if the source of the fire is still very hot, the fire can self-ignite again. The CO2 extinguisher is most successful in the hands of a trained person. CO2s are not suitable for burning paper or soft furnishing.
Dielectrically tested foam extinguishers are suitable for live electrical appliances with a voltage of up to 1000V (4x normal office voltage) at a safety distance of 1m. Special wall signswall signs are available for dielectrically tested foam extinguishers to ensure the correct information is displayed. Foams, while not as easy to spray into hard-to-reach areas such as within a computer, have the advantage that they cool and cover hot areas effectively and prevent re-ignition. They are also a lot easier to use for lay people and can be used on paper and other fires as well.
Dielectrically tested water mist fire extinguishers contain pure de-ionised water, which does not conduct electricity at all. The fine spray also prevents the arching of any current. Again, a limit of 1000V at 1m distance applies. Water mist extinguishers are extremely versatile and do not leave any residue and therefore cause very little damage. The mist causes very little damage to electronics and electrics. A superb all-rounder in offices.
Reviewed: 29/10/2020 (doc:5 V1.1). Our articles are reviewed regularly. However, any changes made to standards or legislation following the review date will not have been considered. Please note that we provide abridged, easy-to-understand guidance. To make detailed decisions about your fire safety provisions, you might require further advice or need to consult the full standards and legislation.