Advantages Of Water Mist Systems Over Other Fire Suppression Systems
For commercial use, water mist systems follow a different set of rules from other fire sprinkler systems. They serve as an alternative to other fixed fire protection systems, and became popular in the 1990s after the International Maritime Organization (IMO) required ships with more than 36 passengers to install fire suppression systems. Water mist systems were further engineered and researched in the UK after the fire extinguishing agent Halon was banned in in 1999 due to the damage it causes the Earth’s ozone layer. (Halon fire extinguishers are mainly permitted in the Channel Tunnel, for the military, on board aircraft, etc.).
Different Ways to Categorize Water Mist Systems
Water mist systems can be divided in three categories: low-pressure (less than 175 psi), intermediate pressure (175-500 psi), and high pressure (greater than 500 psi) systems. Alternatively, they can be categorized based on their design: pre-engineered, or engineered. Engineered water mist systems are meant to contain, control, and suppress accidents due to hazards in a specific environment. The nozzle pressures and flow rates are set accordingly.
Water mist systems can also be differentiated by application:
- Local system – these water mist systems spray straight onto an object or hazard.
- Occupancy protection system – such systems are installed in a portion of a building or throughout a building.
- Zoned application system – these are meant to activate in a certain area in a given space.
Capable of controlling Class A (ordinary combustible fires), Class B (flammable liquids), and electrical fires, water mist systems are used widely in warehouses, storage vessels, buildings, etc.
They are effective against electrical hazards, gas jet fires, and in railway tunnels, and are safer to use on electronic equipment – and easier to clean – than dry chemical systems after use in fires caused by flammable liquids.
In open air spaces a water mists system is not suitable as the micro water droplets may struggle to smother the flame and suppress the heat and oxygen levels. Water Mist Systems cannot be used directly on certain materials, liquefied gases and chemical compounds that react poorly with water and we suggest professional advice is always sought prior to deciding about your fire suppression needs for a specific location.
Advantages of Water Mist Systems
According to a BRE questionnaire (dated back in 2005), water mist systems are favoured over other fire protection systems for certain types of buildings because:
- Quality control and reliable design.
- They perform better than residential sprinklers, according to test data, and offer better protection.
- Do not depend on mains water supply.
- Suppress fire early, and so are more beneficial than other suppression systems.
- More suitable in spaces where equipment can suffer from water damage, or water may cause an explosion (generators, boiler rooms, etc.).
- Easier to take out and install when downsizing from one premise to another.
- More cost-effective than sprinklers.
- Tamper-proof.
- Installed by approved contractors.
- Offer more design flexibility without compromising on safety.
