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3 © 2011, Safe Workplace Promotion Services Ontario, publicly known as Workplace Safety & Prevention Services. 1 877 494 WSPS (9777) | 905 614 1400 | www.wsps.ca Fire Extinguishers selection Using the wrong extinguisher to fight a fire can have serious results. For example, if a water- based extinguisher is used on a flammable liquid fire (Class B fire), the fire may flare up, spread, and cause personal injury to the user and others. If a water-based extinguisher is used to fight a fire, in or near electrical equipment (Class C fire), the user could suffer an electric shock. Follow these steps in selecting extinguishers for your workplace: 1. Conduct an assessment to identify your fire hazards and determine the type of extinguishers needed. The extinguishers you select must match the classes of fire most likely to occur. Remember to check your material safety data sheets to identify materials that could catch fire. The section on fire fighting measures give information on the type of extinguishing agent needed to put out a fire involving the material. 2. Determine the size of potential fires in each area and how fast they could spread. Extinguishers for Class A and Class B fires are rated for the size of fire they can handle. This rating appears on the label and is expressed as a number from 1 to 40 for Class A fires and 1 to 640 for Class B fires. The higher the number, the larger the fire the extinguisher can put out. However, the higher the rating, the heavier the extinguisher. Extinguishers rated 2A:10B:C are suitable for home or office fires. Extinguishers for Class C fires depend upon such factors as the size of the electrical equipment, how it is constructed, whether it is enclosed, and the nature of the other combustible materials in the area. Agents for Class D fires should be carefully selected based on information in the material safety data sheet and the manufacturer's recommendations. The amount of agent needed depends on the surface area of the metal, and its shape and form. Consult the Ontario Fire Code or your local fire department to determine the number of fire extinguishers you need for your workplace. 3. Consider other factors that affect selection: – Possible health and safety hazards from chemical reactions between the extinguishing agent and the burning materials, or when using certain types of extinguishers in unventilated areas. Extinguishers with long-range nozzles, for example, are available for use in confined spaces or other hazardous areas. – Atmospheric conditions in areas where extinguishers are located. Extreme cold, for example, could make water-based extinguishers ineffective. Where there may be corrosive fumes, select fire extinguishers that can resist corrosion, or provide protection against corrosion. – Physical abilities of the user. The size and weight of extinguishers should match the physical abilities of those who have to use them. Extinguishers shouldn't be too heavy for employees to handle. 4. Make sure that your extinguishers: – Are approved by a recognized laboratory (replaced or new extinguishers must be approved by the Underwriter's Laboratories of Canada or ULC, and labelled as such) – Do not contain carbon tetrachloride, methyl bromide, or other toxic vaporizing liquids 5. Do a reassessment whenever you make changes in your workplace, e.g., when you change a work process or the materials you are using.

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