Can powder fire extinguishers be used indoors?
Powder fire extinguishers are versatile and can be used on Class A, Class B, Class C and electrical fires. They also usually have much higher firefighting ratings than other types of fire extinguishers. So why would you not simply just use powder fire extinguishers in your office or shop? It would be simpler because there would only be one type of fire extinguisher and you would need less. There are several reasons which we will look at below.
One of the problems with discharging powder extinguishers indoors is the amount of mess created which can sometimes involve extended periods of time and cost in cleaning up. The powder may be sucked into I.T equipment and heating and ventilation systems by fans and settle on hard-to-reach surfaces. In 2006 vandals set of powder fire extinguishers in a church in Spalding which caused powder to adhere to tapestries, metalwork and stonework which then required cleaning. Additionally, the church organ had to be dismantled and cleaned piece by piece. The final cost of cleaning came to £240,000.
BS 5306 is the British Standard for fire extinguishing installations and equipment on premises. Section 5.4.3 of Part 8 states that powder fire extinguishers should generally not be specified for use indoors, unless mitigated by a health and safety risk assessment. When discharged inside buildings powder extinguishers can create a large cloud of powder in the air. This can create a sudden reduction in visibility which can obscure exits and escape routes. The powder can also cause respiratory distress if inhaled which would pose a particular risk to occupants with respiratory conditions such as asthma.
In normal circumstances it is unlikely that a justification could be found for specifying powder fire extinguishers for use indoors in buildings such as offices or shops. In the past we have found that some companies have tried to save money by buying powder fire extinguishers off of the internet for use in their offices. They have incorrectly thought that they would save money by buying online and that they would also save money by buying just one type of fire extinguisher. However, in this situation there are no general fire risks that require powder fire extinguishers and the more common types of fire extinguisher such as water, foam and carbon dioxide would provide adequate cover without the inherent risks of using powder indoors.
When can you use powder fire extinguishers indoors?
Powder fire extinguishers will normally only be specified for use indoors where there is a specific fire risk that requires their use and where a health and safety risk assessment has been carried out. Some of the instances where powder fire extinguishers may be provided for indoor use may be places like car repair garages or workshops where there is the possibility of running fuel fires or where there are flammable gasses present. Normally the fire risk assessment for a premises will specify the type and quantity of fire extinguishers required.