Description
Carbon Dioxide (CO2) Fire Extinguishers are suited to extinguishing electrical fires in offices, medical rooms and for computer equipment. Their advantages include rapid ability to smother small fires (deprive the flames of oxygen or other oxidizing gases) and that they do not leave damaging residue in equipment; as does dry powder and foam, for example. Carbon dioxide does not conduct electricity (unless at very high voltage) but being a dipolar gas, it readily generates static electricity, through friction, when released under pressure. This may cause sparks. Because of the advantages CO2 is suggested for fighting electrical fires and it is also useful for tackling small gas fires, such as might be encountered in a laboratory, or small workshop. The disadvantages of Carbon dioxide as an extinguishing medium are that, although flames may be smothered by it, very little heat of combustion is removed and often, after the gas has rapidly dissipated to atmosphere, enough heat is left in the combustion material that it re-ignites, after the fire has apparently been put out. Also, there are dangers to the fire-fighter, in so far as the extinguisher releases asphyxiant gas in to the atmosphere. Broadly, every litre contained under pressure will expand to a cubic metre of pure gas. The Work Place Exposure Limit for CO2 is just 4500 parts per million, or a little under half a percent. Thus the contents of a 5 litre extinguisher, for example, may compromise safe breathing in up to 10 cubic metres of air space, or the volume of a small room. The effects of Carbon Dioxide poisoning are detailed elsewhere in out web site and are available from the HSE, in Guidance EH40. There are roles where CO2 is a useful extinguishing medium but, in general, it is the least effective of the common media open to you. For electrical fires, Dry-powder has a better 'knock-down' effect and remains intumescing and smothering the hot surfaces for some time after discharge from the extinguisher. Technical Specifications: Freeze resistant swivel horn. Test protocol: BS EN3, BAFE, CE Marked, Fire rating 70B Mounting bracket included Dimensions, mm (approx.) 760 x 150 (cylinder diameter) Filled weight, approx. 11 kg Discharge time approx 18 seconds Operating temperature -20 to 60°C