Thousands of fires happen at construction sites every year, resulting in millions of dollars in damage and threatening the health and safety of workers, emergency responders and surrounding communities. A fire can double in size every 30 seconds, and when a construction project is still in its early stages (before smoke detectors and sprinkler systems have been installed), a fire can cause substantial property loss.
“Fire extinguishers are the first line of defense and can often prevent a disaster when used promptly,” says LHSFNA Management Co-Chairman Noel C. Borck. “Routinely checking fire extinguishers to make sure they work, making sure employees know where portable fire extinguishers are located and training employees on how to use them can save lives and minimize property loss.”
However, in order to do the job, workers must choose the right kind of fire extinguisher from many different types. Fires start for all kinds of reasons and are classified by what is fueling them. Flammable and combustible materials including wood, paper, plastic, paint and gas are often linked to construction fires and these materials dictate which fire extinguishers are appropriate for a particular site. Using the wrong one can make a fire even more dangerous. For example, turning a water and foam extinguisher on a smoldering circuit breaker can create a shock hazard.
All fire extinguishers are color-coded and labeled to indicate the class of fire they are effective against. That is why it’s also important to be familiar with fire classification.
Classes of Fire
- CLASS A: Fueled by common materials such as wood, paper, cloth, rubber, trash and plastics.
- CLASS B: Fueled by flammable liquids including gases, solvents, oil, gasoline, paint, lacquers, tars and other synthetic or oil-based products. Class B fires often spread rapidly and can reflash after the flames are extinguished.
- CLASS C: Fueled by energized electrical equipment such as wiring, controls, motors, data processing panels or appliances. Class C fires can be caused by a spark, power surge or short circuit and typically occur in locations that are difficult to reach and see.
- CLASS D: Fueled by combustible metals such as magnesium and sodium.
- CLASS K (USA) or Class F (Canada): Fueled by cooking media such as oils and grease commonly found in kitchens. These fires can be extremely hot and also have the ability to reflash.
Types of Fire Extinguishers
- Water and Foam: Class A and Class B fires.
- Carbon Dioxide: Class B and Class C fires.
- Multi-Purpose Dry Chemical: Class A, Class B and Class C fires.
- Wet Chemical: Class K (Class F) and Class A fires.
- Clean Agent: Class B and Class C fires.
- Dry Powder: Class D fires.
- Water Mist: Class A fires.
- Cartridge-Operated Dry Chemical: Class A fires.
What’s the Difference Between Flammable and Combustible Materials?
The difference is their flash point or the lowest possible temperature at which they burn.
Materials that are flammable can catch fire and burn at normal working temperatures. Gasoline, diesel fuel and paint thinner are examples. Only approved containers and portable tanks shall be used for storage and handling of flammable liquids. For more specific requirements for flammable materials refer to OSHA 1926.152.
Combustible materials require higher than normal temperatures to ignite. Wood, plastic and coal are examples. Combustible materials in a work area should only be present in the necessary amount. Combustible waste like sawdust should be stored in a metal container and disposed of every day.
It’s also important to know when the best plan of action is to leave the jobsite immediately and call 911. Employers should update their evacuation plan as conditions change over the course of a project and hold periodic fire drills so all employees know how to respond.
OSHA standard 1926.150 requires employers to implement workplace fire protection and fire prevention plans at construction sites. The LHSFNA’s Occupational Safety & Health Division can provide guidance in setting up a fire protection and prevention plan specific to your worksite. This includes site visits and a review of an employer’s safety and health program. The Fund’s online Site Safety and Health Program allows signatory contractors to create individual safety and health programs customized for their specific needs. For more information, call 202-628-5465.
[Janet Lubman Rathner]