Sprinklers and misting systems

Contents


Automatic fire suppression systems

Automatic fire suppression systems are defined as "A method to control and extinguish fires without human intervention".

The system must include a means of:

1. Detection – An automatic way of detecting the presence of smoke, heat and/or fire

2. Actuation – An automatic method for discharging the suppressing media

3. Delivery – A method of delivering the media to the location of the fire

This can be achieved through many different methods, the most common being sprinklers or misting systems.

There are often fears that these create unnecessary water damage. In fact, the only heads that activate are those directly affected by the fire. Sprinkler and mist systems use much less water to extinguish a small fire than firefighters, who use jets designed to extinguish a much larger, fully developed fire.

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Sprinklers

Advantages

  • Rapid knock down of flaming fires
  • Good compensatory features for non-compliant buildings
  • Good penetration into fires due to the much larger droplet size
  • Can be used in areas subject to air movement

Disadvantages

  • Water damage is more than other systems
  • Good water supply required – either mains or tank, or both
  • Expensive to fit due to the cost of the heads, pumps, tanks, and pipework required
  • Larger components, so these are more difficult to conceal on retro fit-outs

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Mist Systems

Advantages

  • Approximately 85% less water required, so less space required and tanks may not be required, as the town main may be sufficient
  • Rapid knock down of flaming fires
  • The small droplets vaporise faster, absorbing heat and replacing oxygen
  • Increased surface area of the smaller droplets
  • Less damage to the contents, due to less water being used.
  • Shielded fires can still be tackled, as the fire plume draws cooler air into the fire, carrying the water droplets in and under any covering materials
  • Cheaper to fit than sprinklers
  • Low power requirements due to smaller pumps
  • Less space required for the smaller pipes and components

Disadvantages

  • Higher pressure required to run the system
  • Does not work effectively in open area situations
  • Does not work well in areas subject to air movements

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Further guidance

Further guidance on these systems is available on the British Automatic Fire Sprinkler Association website.