Water Mist Systems vs Fire Sprinklers

Have you ever wondered about the benefits of water mist systems? Or maybe the difference between those and traditional fire sprinkler systems?

In this article, we will talk through the popular firefighting agents, their suitability, advantages, disadvantages and system designs.


How do water mist fire suppression systems work?
Accreditations and Certifications of fire fighting agents
What is the suitability for fire suppression systems?
Advantages and disadvantages to firefighting agents (including price)
System designs of water mist systems and fire sprinklers
Why choose iMist for your fire suppression needs

What is a water mist fire suppression system?


A water mist system is a fire protection system that produces a fine spray to suppress fires – a common alternative to traditional large droplet, fire sprinklers. Water is the oldest, most widely used, and universally available firefighting agent known to man. It is non-toxic, environmentally friendly and, in addition, has superior fire protection capabilities when compared to every other agent.

health and safety manager at site on imist
imist van installation in manchester fire suppression system
iMist installer installing iMist nozzles in a domestic house

How do water mist fire suppression systems work?


The iMist suppression system and traditional fire sprinkler systems work in the same way when it comes to activation when there is a fire. Both systems wet the surface of the fuel, and the surrounding area, to cool and suppress the fire like a blanket of water. However, only the water mist system works in all three ways simultaneously, with minimal water to extinguish a fire;

  1. Upon activation of a water mist nozzle, the system will begin to discharge high pressure water mist. The mist will fill the 16m2 area (per nozzle) with a fine mist – which will travel around the room, dampen all surfaces it can get to and thus, restrict fire spreading.
  2. When the water is discharged at a high pressure, the room temperature is reduced dramatically due to a reaction between the fast-moving colder air molecules and water molecules against the heat from the fire, much like cold air displacing hot air.
  3. As the water mist has direct contact with the flame, it turns into steam. The steam particles then displace the oxygen particles around the fire and thus, suffocates the fire.

Unlike many Hollywood films, only the nozzles situated in the area of the fire will release the mist.

Fire triangle for iMist
water mist systems vs fire sprinklers table

What is the suitability for fire suppression systems?


Fit for purpose: When protecting you and your family, especially the vulnerable, it is extremely important for systems to activate as soon as possible to minimise the build-up of smoke, and to buy people time to evacuate the building safety. 

Water supply: iMist only requires 6 litres per minute, per nozzle (lpm) (that’s a flow rate less than a power shower), this negates the need for tanks in the home. 

System designs of water mist systems and fire sprinklers


Both water mist and sprinkler systems have fixed nozzle heads, that have been accurately and efficiently positioned within the property to ensure full protection.

At iMist our water mist nozzles are discreetly designed to blend in with your ceiling fittings, and can be produced in any RAL colour to suit your needs. 

imist nozzle spinning animation fire suppression


Water mist systems use less water than sprinkler systems which means there is less post-fire damage to the property. In properties with low water flow, a mist system may be more appropriate, because traditional sprinkler systems need big water tanks installed inside the property for the system to work – which will be additionally required to ensure adequate water low.

At iMist fire suppression systems, we negate the need for a large tank, and instead use our own small tanks that can fit conveniently in small spaces such as under the stairs.

iMist Fire Suppression Pump


Both water mist and sprinkler systems have fixed pipe work. 

iMist use their own custom hydraulic hoses which offers the possibility to retrofit fire suppression systems into properties, due to the flexibility of the hose.

imist backpack with imist custom flexible pipework

Accreditations and Certification of fire-fighting agents

Both water mist fire suppression systems and fire sprinkler systems have many accreditations and certifications that they can gain to ensure the reliability and effectiveness of their system, components and materials. The publication of a British standard for example, has produced specific criteria which water mist suppression systems and components can be measured against. 

The main difference between the 2 fire fighting agents is that conventional fire sprinkler systems have been in use for over 100 years, whereas mist systems have only been developed in the last few decades – but have extensive data, knowledge and testing to back up what they are doing currently. 

Another difference between water mist systems and fire sprinklers is the ‘categories’ that define themselves. 

See below an example of the British Standard that states Automatic Water Fire Suppression Systems (AWFSS) must be installed in the following circumstances

Water Mist Fire Suppression Systems

water mist fire suppression system British standard for when a AWFSS needs be installed BS:8458:2015

Fire Sprinkler Systems

water mist fire suppression system British standard for when a AWFSS needs be installed BS:9258:2014

Advantages and Disadvantages to firefighting agents

Water Mist Fire Suppression

Fire Sprinklers

Water mist fire systems require less water than fire sprinklers, on an average of 80%. Therefore, water mist is more environmentally friendly as the iMist nozzle requires an average of 6 litres per minute (lpm). Less water means that our iMist pump(s) can fit in the most convenient places such as under the stairs or under the kitchen sink.Fire sprinklers require more water, a minimum of 51 lpm per sprinkler. Sprinklers usually require a tank to be installed in your property, meaning that you could be loosing out on expensive square meterage.
Due to the water mist particles being able to evaporate quickly and less water needed to dispense, it means water mist systems cause less damage if the system activates on an average of 0.375 mm per minute.Fire Sprinklers dispense 2.04 mm water per minute, which causes more water damage compared with water mist. 
Water mist systems combat all 3 sides of the fire triangle, by suppressing the oxygen, heat and fuel. The most common cause of death for fire-related fatalities in 2017/18 where the cause of death was known was ‘overcome by gas or smoke (30%)’, which water mist minimises.Sprinkler systems suppress fires by wetting the fuel surface.
When it comes to cost for water mist systems, the cost includes labour, pipework, nozzles and pump(s). At iMist, there are no hidden costs or sudden surprises. Once you approve our quotation, this is the price you will pay. With fire sprinklers, there’s many instances where you may need to purchase/install additional systems to comply with the sprinklers, such as water connections to run under your property.

Please note: It is compulsory by law that both water mist and sprinkler systems are serviced annually to ensure the system is in working order and would be effective in the event of a fire.

imist fire suppression comparison table with fire sprinklers

Why choose iMist for my fire suppression system?

We have been designing, manufacturing and installing iMist water mist fire suppression systems for our clients across the UK for 5 years. We have worked hard on obtaining and passing many third-party accreditations, and are now one of the most comprehensively tested and well-known water mist fire suppression systems. 

Some reasons we think you should choose us for your water mist fire suppression system are;

    • 109 years of combined industry experience
    • Well-known for the service we provide
    • Free 24 hour turnaround designs and free site visit to your property
    • Third-party accredited (see our list of certifications and reports on our website)
    • Cost certainty with no hidden costs or sudden surprises


Yes, depending on the nozzle layouts and ventilation condition. Water mist systems get successfully tested for tunnel and outdoor fires, and in test cells with windows/doors open. Once you’ve decided on a company, they will be able to show you where is accurate to place your nozzles and system.

Some companies, including iMist, can be connected to third party systems such as fire panels, fire alarm systems, AOVs (Automatic Opening Vent), SMS units, fire curtains and more.