What is Water Mist?
Water mist is a highly efficient fire suppression system which uses specially designed nozzles to create a fine mist. Where water mist shows its real advantage is that it combines the fire suppression effect of gas systems (by preventing fresh oxygen reaching the seat of the fire) and traditional sprinkler systems (more efficient way of cooling the fuel / material), using much less water in the process.
The nozzles atomize the water into micron-sized droplets, which rapidly expand into steam when they come into contact with a fire, depriving the fire of oxygen.
A fire requires the presence of three elements: oxygen, heat, and combustible material. This is usually referred to as the fire triangle. Water mist systems, as opposed to standard sprinkler systems, provide fire suppression by eliminating both heat and oxygen from a fire by spraying pressure water via specially engineered nozzles. The nozzles atomize the water into micron-sized droplets that quickly burst into steam when they come into contact with fire, depriving it of oxygen.
Water mist fire suppression is not a new technique; it has been used since the nineteenth century and has proven to be successful in marine applications, where it has saved many lives. It was not commonly employed in land-based applications until the Montreal Protocol prohibited the use of halon gas as a fire suppression in the 1970s. Following the 1990 Scandinavian Star Disaster, the technique became more commonly used.
In addition, water mist has a cooling effect on the surrounding area, which prevents reignition of the fire source and any other material that may have caught fire.
Types of water mist systems
There are three types of water mist systems and the primary difference between these is their operating pressure:-
Low-pressure, Medium Pressure, and High-Pressure water mist systems.
Hydrocore High Pressure Water Mist Systems
- Minimum Discharge Pressure at nozzles: 100bar
- System operating pressure: 105bar to 140bar
- Droplet size: Dv0.99<1000μm
- Power required: 30kW to 240kW
- Pump unit discharge capacity: 100lpm to 800lpm
Hydrocore Low Pressure Water Mist Systems
- Minimum Discharge Pressure at nozzles: 10bar
- System operating pressure: 11bar to 15bar
Extensive Testing
Extensive testing and experience have shown that water mist systems deliver the following advantages:
- Ease of maintenance: The use of water without any chemical additives and the use of high-pressure stainless steel piping (for HPWM systems) makes the system corrosion-resistant, enhancing system life and reducing maintenance costs.
- Quick and efficient fire suppression: The atomizing effect of water mist offers reliable and effective fire suppression.
- Minimal Damage: Atomized mist causes a quick vaporization effect which limits water and fire damage.
- Low downtime: Quick recovery and less downtime compared to other suppression systems which need servicing or recharging post activation, this means you can get back to work quicker. In a large application, the downtime cost could easily be millions if a facility is shut for a week or more.
High Pressure Water Mist Nozzles
Hydrocore has a range of high pressure water mist nozzles both of open and closed types. Open nozzles are designed to offer a total flooding or a deluge effect while the closed nozzles offer a targeted response.
- Closed Nozzles
- Hydrocore Closed (bulb) Nozzles are made of stainless steel.
- They are used in wet-pipe systems for the protection of Light Hazard Occupancies, an occupancy where the quantity and/or combustibility of contents is low and fires with relatively low rates of heat release are expected.
- The nozzle discharges water at 35.0l/min at normal working pressure.
- Each micro nozzle has an integral filter.
- Open Nozzles
- Hydrocore Open Nozzles are manufactured from stainless steel and are used in dry-pipe systems for the protection of machinery spaces, as part of a total flooding system.
- Total Flooding systems use open nozzles (they have no fusible element) spaced throughout a compartment.
- In this dry pipe system, the water is only contained in the pipework prior to the section valve, until automatically released by a signal from the Fire Detection System (FDS) or manual activation.
At AITO Firework Sdn Bhd, we do sell fire extinguishers among an extensive range of fire safety equipment. In addition, we offer education and training to help you, your organization or your business to operate the equipment effectively. To inquire further, contact our friendly team today
