Fire Safety Planning Part 3

Fire Safety Planning Part 3

Suppression

Once you have alerted co-workers that there is a fire in the building or jobsite, the next step is to try to put out the fire. Many different systems have been created to try and do this. Some are quite common, such as sprinkler systems and fire extinguishers. Others are more specialized to deal with unique hazards or to protect equipment that may be damaged from using water. Suppression systems work by removing one of the components of the fire triangle, either heat or oxygen.  Fire Safety Planning Part 3 will look at the systems that can be put in place to put out the fire.

Fire Extinguishers

Fire Extinguishers are found in almost every building, even those still being built. These hand held units have been around for almost two hundred years and have evolved from using acid and baking soda to propel water to having chemicals that can be used to control different types of fires. There are six classes of fire extinguishers

Class A: Solids such as paper, wood, plastic etc.

Class B: Flammable liquids such as paraffin, gasoline, oil etc.

Class C: Flammable gases such as propane, butane, methane etc

Class D: Metals such as aluminum, magnesium etc.

Class E: Electrical fires

Class F: Cooking Oil and fat

When selecting the type of extinguisher you need, look at what work is being done and what equipment and materials are being used. A Class ABC will be appropriate for most work places. If you have an electrical room or computer/control room, then you will need a Class E. An assessment must be done to determine what you need. It is also important that a system be in place to check the fire extinguishers monthly and annually.

Staff should be trained on how to use a fire extinguisher. In Canada, only authorized personnel can use a fire extinguisher. Check to see who offers this type of training in your area.

Automatic Sprinkler System

Automatic sprinkler systems are the next most commonly used suppression system. All public buildings in Canada should have one, based on the size. There are a lot of myths about how a sprinkler system is activated. When there is a fire, the heat will activate a sprinkler head near the fire, not the whole system as shown in some movies or TV shows. This keeps the water damage to a minimum. The sprinkler heads themselves activate at different temperatures, depending on what is required for the building or room. The fusible links or bulbs colour coordinated to show what temperature they are set to.

There are four types of sprinkler system:

  1. Wet- This type of system is used when a building has a constant temperature of 40° F (or 4°C). Water is always in the pipes when needed and thus have the quickest reaction time
  2. Dry System- If the building or location is below 40°F, then a dry system is needed. Water is not maintained in the system. Instead, air is maintained under pressure. When a head is activated, the air is expelled before the water can start flowing
  3. Deluge system- there are no fusible links or bulbs on the heads. Instead, a fire alarm system must be activated which activates a valve connected to the heads. Deluge systems are only used when there is a high hazard in the area.
  4. Pre-Action System- Similar to the deluge system in that it is connected to the fire alarm system for activation. The difference is that while a deluge system dumps water right away, the pre-action will send water to the pipes connected to the system. When a head is activated, then it will start to fall on the fire.

Most sprinkler systems are found in urban or suburban areas and are connected to the municipal water supply. In rural areas or in places that don’t have municipal water supplies, tanks are used to store the water for the sprinkler system until needed. All parts of a sprinkler system need to be checked annually. If you have a tank, it is necessary for the inspectors to enter and check for damage. The department of labour (in Nova Scotia) also must inspect the tanks and certify that they are in good condition.

Gas Suppression Systems

In situations where using water would either be dangerous or ineffective, gas based systems are used. These systems work by reducing the oxygen available for the fire to use. In some cases, this can make them dangerous for humans to be in the same room. All chemicals used are connected to a fire alarm system through a solenoid. When a detector or detectors go off in a room, the solenoid is activated to release the gas into the room.

Carbon dioxide was the first chemical to be used in this capacity. It started to be used as a fire suppressant during World War One. It has since fallen out of use because it removes the oxygen in the air to below what humans can survive in, although you can still find it being used in fire extinguishers. Halon was the next innovation. There are different types of halon, and it is much safer then carbon dioxide for humans, but it has a negative impact on the environment and it releases hazardous chemical when they break down in temperatures. Halon has thus ceased being used and now there are numerous halon equivalent chemicals used that are safer, both to humans and the environment.

Conclusion

By having effective systems in place, a company can reduce the damage that a fire causes. Fire suppression systems also save lives. It is for these reasons that as fire safety planning part 3 is further looked at, then we can see how the use of these systems, from installation to maintenance, can increase safety in the workplace.

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