Water Mist Systems
The fire triangle and water mist systems
Fuel, heat and oxygen are frequently referred to as the “fire triangle”.
When all three of these elements react together in time and space, a fire occurs. By removing, reducing or separating these components, a fire can be controlled or extinguished.
Definitions:
- Fuel: This can be any kind of combustible material, such as paper, wood, oil, fabrics, etc. Some materials burn more easily than others.
- Heat: A heat source is typically responsible for the initial ignition of fire. Not all fires burn at the same temperature – different materials offer different amounts of heat. Combustion reactions also produce heat as they burn, further increasing the temperature, as such maintaining the fire and enabling it to spread further.
- Oxygen: Our normal air contains 21 % oxygen. Most fires require an oxygen level of at least 16 % to burn. The chemical processes that occur during a fire are supported by oxygen. When fuel burns, it reacts with oxygen from the surrounding air, releasing heat and generating combustion products (gases, smokes, etc.)
The type of fire and the available fire protection system or firefighting equipment dictate which element of the fire triangle should be targeted in order to suppress the fire.
Water mist generally has an effect on two of the three sides of the fire triangle: the heat and the oxygen. A secondary effect for the third element of the triangle is achieved by wetting the surroundings.
- Cooling effect: The small droplets created by water mist systems increase the surface area to maximize the efficient absorption of heat.
- Oxygen displacement: The small water droplets evaporate rapidly and expand to displace oxygen in the proximity of the fire.
- Radiant heat attenuation: The small droplets provide effective protection from radiant heat.
Did you know?
Tiny little candle flames can reach really high temperatures!
The outer core of a candle flame typically burns at 1,400°C,
and the blue core of the flame at 800°C.
A little bit of history
Water mist primarily evolved as a water-based suppression solution for marine applications, driven by two incidents. The first one was the execution of the Montreal protocol on “substances that deplete the ozone layer” in the late 1980s, which led to the phase out of halon, a bromine-based chemical fire suppression agent which was widely used until then.
The second incident was a devastating fire on the passenger ferry “Scandinavian Star” on the morning of April 7, 1990, where nearly 50% of passengers died. This catastrophy led to an improvement of the International Maritime Organisation’s (IMO) fire safety requirements and installation guidelines as well as fire test procedures for alternative sprinkler systems.
Fast-forward to today, land-based water mist solutions designed in accordance with EN 14972, VdS 3188, FM 4-2 & NFPA 750 are now recognized as solutions to protect a variety of risks.
Addressing the challenges faced by the modern and existing built environment requires a multifaceted approach encompassing technology, sustainability, safety and meeting the requirements of the customer. By implementing innovative solutions, we can create safe environments and prepare for future demands. We strongly believe that water mist will have a role to play in the approach of fire protection in such applications.
Water mist, be it high pressure or low pressure technology, can offer end-users the benefit of saving valuable space and lower operating costs. And they can be re-assured that the different water mist systems available from Viking come with the necessary approval or accreditation.
Viking’s low pressure water mist systems
Image source: Viking S.A. | Laura Hope on Unsplash