CLASSIFICATION OF FIRES

SIGN, COLOUR & PICTOGRAM			CLASSIFICATION OF FIRES
fire class a Wood / Furnishings etc			CLASS A: All solid materials, usually organic origin nature (contains compounds of carbon) and generally produce glowing embers – i.e. wood, textiles, curtains furniture and plastics.
fire class b Flammable Liquids & Solids			Class B: All flammable liquids and solids, which can also be sub-divided into: · Non-miscible (non-Polar) with water (i.e. petrol, oils, solvents, paints & waxes); · Polar Liquid Fires (Hydrophilic/Miscible) with water (e.g. alcohol, methanol, acetone, propanol, etc.) – sometimes known as Polar Liquids; Note: Hydrophilic = having an affinity with water / Miscible = ‘capable of being mixed’ ordinary foams are designed to work on non-polar flammable liquids such as petrol, but may break down too quickly in polar liquids such as alcohol or glycol. Facilities that handle large amounts of flammable polar liquids use specialised “alcohol resistant foam” instead.
fire class c Fires involving Gases			CLASS C: Class ‘C’ fires involve Natural Mains Gas, Liquid Petroleum Gases (LPG) such as Butane & Propane etc. This class includes Medical or Industrial gases.
fire class d Fires Involving Metals			CLASS D: Class ‘D’ fires involving metals or powdered metals etc (where water is generally ineffective and / or dangerous). Specialist Dry Powders – are produced for certain Metal fires particularly those involving alkali metals such as Sodium & Potassium. These dry powders extinguish metal fires by fusing the powder to form a crust, which excludes oxygen from the surface of the molten metal. A specific agent is added to prevent the powder from sinking into the surface of the molten metals. Some Class D extinguishing agents include finely granulated sodium chloride, copper and graphite applied by an extinguisher, shaker, scoop or shovel. M28 type – 9Kg dry powder fire extinguisher these extinguishing agents are suitable for sodium, potassium, magnesium, titanium, aluminium, and most other metal fires. This particular fire extinguisher is not suitable for fire involving Lithium. Normally used with a low velocity discharge applicator. L2 type – 9Kg dry powder fire extinguisher is suitable for metal fires involving Lithium. Normally used with a low velocity discharge applicator.
electrical Electrical			ELECTRICAL: Electrical fires are not considered to constitute a fire class on their own, as electricity is a source of ignition that will feed the fire until removed. When the electrical supply has been isolated, the fire can be treated (generally) as ‘Class A’ for extinguishing purposes. However, you should always isolate the supply before fighting the fire; if this is not possible then a non-electrical conducting extinguishing agent is to be used regardless of the power status, on all occasions. Warning Note – some electrical equipment can store in capacitors, lethal voltages even if their power supply has been isolated. Always use extinguishers containing a non-electrical conducting extinguishing agent specifically designed for use on electrical equipment such as Carbon Dioxide (CO2) or Dry Powder.
fire class f High Temperature Cooking Oils			CLASS F: New class specifically dealing with high temperature (³ 360°C) cooking oils used in large industrial catering kitchens, restaurants and takeaway establishments’ etc. Cooking oil fires, because of their high auto-ignition temperatures, are difficult to extinguish. Conventional extinguishers are not effective for cooking oil fires, as they do not cool sufficiently or may even cause flash back, thereby putting the operator at risk. These extinguishers contain a specially formulated wet chemical which, when applied to the burning liquid, cools and emulsifies the oil, extinguishing the flame, sealing the surface and preventing re-ignition.