Extinguishing media

• Water extinguishers. Ordinary water units commonly cool Class A solids. Do not use them on live electrical equipment, flammable liquid or cooking-oil fires. Specialised products can have different ratings; follow the marked suitability and training rather than assume a universal range.
• Foam. Suitable for Class A and B fires. It works by smothering the fire or by stopping combustible vapours from mixing with air.
• Dry powder. ABC and BC powders have different marked uses. Metal fires need specialist powders selected for the metal; ordinary powder must not be assumed suitable. Powder gives limited cooling and may impair breathing and visibility, especially indoors. Its operating range is product-specific.
• Carbon dioxide extinguishers. Suit some Class B and electrical risks and leave no extinguishing residue. They give limited cooling, so reignition is possible, and discharge can create a breathing hazard in confined areas. Use only within training and the emergency plan, following the product instructions rather than a generic stand-off distance.
• Wet chemical. These extinguishers use a pressurised solution of alkali salts in water and are used on Class F cooking oil and fat fires. Their main use is in kitchens and food processing plants.

Access for fire and rescue services and vehicles

An emergency can escalate quickly, and external agencies such as neighbouring industry or the local fire and rescue service may be needed. Define the routes by which emergency vehicles will get in. Remember that fire-fighting vehicles are large, unwieldy and heavy and need significant turning areas, and consider how emergency vehicles can reach the most distant points of your facility.

• Access gates and driveways should meet the minimum dimensions laid down.
• Driving surfaces should be designed to carry the weight of fire and rescue vehicles.
• Straight ramp designs should allow for vehicle needs, particularly at the ramp entry and exit points.
• Curved ramps should be considered carefully in relation to vehicle weights and clearances, including overhangs.
• Recesses such as storm water drains should be positioned carefully with vehicle movements in mind.
• Hard-standings should be at the correct distance from the building, from fire-fighting systems and inlets, and from fire-fighting water supplies.
• Consider vehicle loading requirements for attendance and hard-standing points.
• Allow working space for firefighters in and around vehicles.
• Keep access routes clear at all times, particularly of vegetation, parked cars and temporary structures.
• Speed is critical. The sooner fire-fighting starts, the more likely it is that the consequences will be limited.

Summary notes for Element 10 · Cheat sheet · Glossary. A study aid, not published or endorsed by NEBOSH.