Mist Sprinkler Systems
Nationwide Fire Sprinklers now offer water mist fire suppression sprinkler installations to BS8458 (residential), BS8489 (commercial) and to other levels of suppression.
We are helping this rapidly developing field of fire protection to establish safe designs and working practices to develop a practical and functional water mist fire suppression installation suitable for domestic, residential and commercial requirements.
Nationwide fires systems are all low standing pressure systems which are much safer in the residential and domestic application, than high pressure watermist systems.
Benefits of Water Mist Systems
These may include a lower water flow requirement where we can prove that water mist nozzles can actually perform against the fire loading. Customers should note that water mist nozzle manufacturers make certain claims about performance which when tested by independent test houses such as the BRE (see test report below) can be found to not perform as expected.
Nationwide fire has developed and tested with our partners, a range of nozzles which have been tested at the BRE and at the FPA test facilities and all have fully met the testing requirements for BS8458 and BS8489. Our products are one of the few on the market that do meet compliance. Our nozzles are all made from the highest quality stainless steel and are corrosion proof, with decorative blow off coloured caps.
Where we can make water mist effective as a suppression system, there is a benefit in stored water volumes being reduced which helps offset the higher cost of high-pressure pumps that are required.
With the introduction of these 2 new standards from the British Standards Institute, we now have a document to measure the performance of our product against; and to give our customers the comfort of knowing their water mist installation has been designed and fitted correctly.
Types of Water Mist Systems Available
There are a number of different water mist systems on the market, some are ceiling mounted and use aluminium which is not protected from long term corrosion. This risks the plug which holds back the water seizing. There will be a new standard for testing the quality of all nozzles shortly, and part of this standard will be a requirement for “aging” the components to replicate long term corrosion.
Unwitting customers are unlikely to differentiate between aluminium products some of which are over sprayed white, and stainless steel products which will withstand these long term aging tests.
There is a wall mounted system, which is triggered by passive detection (smoke/ heat alarms) but these are prone to accidental unwanted activation and have been known to set off the suppression system causing significant water damage and in at least one incident an occupant has been directly hit by a high pressure jet. These systems are not compliant to BS8458.
High Pressure Water mist Systems
These types of systems usually stand with a pressure of around 100 bar (around 1500 PSI), and the end user is left with the potential for an explosive rupture of the pipework, which could cause serious harm to persons nearby, or the potential failure of the bulb to fracture in a fire event due to its high compression onto its seating .
Components for these systems are expensive, and pump units tend to be crude adaption’s of domestic jet wash pumps which have no fire industry testing or validation.
Low Pressure Water Mist Systems
These types of systems usually stand with a pressure of 7 to 12 bar (102 PSI to 220PSI) and the end user has a system which uses tried and tested pipe materials whose working pressures are well in scope for this type of application. Accidental damage to a pipe such as a screw through a floor board catching a pipe, will not cause an explosive rupture, and risk of injury to persons nearby is minimal.
Installation of Systems
Almost all water mist systems are ceiling mounted, with easy installation by the water mist contractor, through the ceiling/ floor voids causing no damage to existing walls and no “add on” builders work which customers would have to pay for.
Wall mounted systems however, need to have chases cut into walls, complex installation work is expected to be carried out by the customer/ their builder, and significant making good to wall finishes following the installation.
How Water Mist Fire Suppression Systems work
In water mist systems, water is forced through micro nozzles to form a water mist with the most effective fire fighting droplet size.
The water mist can give optimum protection by its cooling effect and also by the “inerting” or elimination of oxygen effect as water expands by a factor of 1700 when it evaporates.
Thus when water mist comes into contact with the fire – heat and oxygen, 2 of the essential ingredients of fire are much reduced or eliminated.
Less water is required in water mist systems than with conventional fire sprinklers systems.
Water mist systems are almost like the spray from an aerosol where conventional sprinklers are more like the water coming from a domestic shower.
Summary of UK Gov Building Research Establishment on commercial applications for water mist fire suppression systems
“Overall, the full-scale test results were of concern. Most water mist system arrangements were not able to provide expected levels of fire protection for the tested scenario (open plan office areas with a high ceiling). Or, in terms of the design of the tested systems, the spacing between nozzles was too great and the quantity of water discharged too low, to provide effective fire suppression.”
Water Mist Systems Accreditation
We are now fully third party certified for the installation of Dualmist systems. Working to the British Standards of BS8489 Part 7:2016 (Light Commercial) and BS8458:2015 and we can offer design and installation on all system types; Commercial, Residential and Domestic.
Working with IFC Group (International Fire Consultants) we have demonstrated our ability to design and install systems to the highest quality standards and are proud to be one of a small group of installers within the UK to have such level of certification.
See a copy of our IFCC 3197 Certificate.
Recent fire trials with mist sprinkler systems
During fire trials carried out with Derbyshire fire and rescue water mist sprinklers were tested to see if they had the capability claimed to reach into concealed fires and suppress them.
The concealed fire which was shielded from the water mist head contained the fire within the cabinet and prevented the fire from developing further, and simultaneously removed heat and gasses from the room of origin, aiding tenability within that room.
Contact us to discuss your requirements for water mist fire suppression systems.