2.15 Automatic fire suppression systems
Every building must be designed and constructed in such a way that, in the event of an outbreak of fire within the building, fire growth will be inhibited by the operation of an automatic fire suppression system.
This standard applies only to a building which:
Automatic fire suppression systems installed in domestic premises are primarily designed for life safety purposes. Successful activation can provide occupants, including vulnerable occupants, with additional time to escape following the outbreak of fire. The added benefit of automatic fire suppression in domestic buildings means that the damage and disruption caused by fire is greatly reduced.
Automatic suppression systems react to heat therefore, the greatest protection is afforded to those occupants outwith the room of fire origin. Automatic suppression may provide some benefit to occupants in the room of fire origin where for example the fire growth is fast and the temperatures allow the sprinkler system (normally 1 or 2 heads) to open early in the development phase of the fire. The spray pattern delivered from the sprinkler heads should control fire spread. Whilst the effect of sprinkler spray will increase the smoke volume and could obscure exits, smoke temperatures and toxicity will be greatly reduced. In some cases, the fire might be extinguished if the fire is not shielded from the sprinkler spray.
While supporting the installation of automatic fire suppression systems in buildings, the Association of British Insurers (ABI) advises that claims involving the escape of water are increasing year on year, costing the insurance industry in Britain £892 million in 2019. Although only a relatively small proportion of this was due to leakage from automatic fire suppression systems, it does nonetheless reinforce the need to ensure that all water supply pipework in buildings, including those serving automatic fire suppression systems, is designed, installed and maintained correctly. The ABI have produced guidance ‘ABI Study: Post Grenfell Research on Residential Sprinkler Systems’ on issues to be considered to improve performance and in the procurement of residential and domestic sprinklers which is available on the ABI website. Although primarily addressing the use of automatic sprinklers, much of the guidance is also applicable to other types of automatic fire suppression systems.
Automatic life safety fire suppression systems are required in 3 categories of domestic building:
The term automatic life safety fire suppression system includes sprinkler systems but provides the opportunity for designers to propose other systems which may be just as effective. The key characteristics of the system are:
it must be automatic and not require people to initiate its activation
it must be designed primarily to protect lives, rather than property, which means it should be fitted with faster responding sprinkler heads, and
it must be a fire suppression system, one designed specifically to deal with fires rather than other hazards.
Concealed or recessed pattern sprinkler heads may be used in the system design. However there is a risk that the heads are rendered ineffective or operate less efficiently by the application of any decorative ceiling finish. Therefore, consideration should be given to labelling of the heads with words to the effect of 'DO NOT PAINT'.
Alternative suppression systems - The applicant and the verifier should satisfy themselves that the alternative system has been designed, tested and approved for use in domestic and residential buildings and are fit for their intended purpose (see Section 0). Watermist systems, for example, are bespoke to individual manufacturers and may be sensitive to small design changes. Therefore, a watermist system should be designed and installed in accordance with BS 8458: 2015 –TC (tracked changes) and the nozzles should comply with BS 8663-1: 2019 (provided the building is within the scope of the standards). Fire performance tests are critical as BS 8458 relies on this data to determine the system design. Watermist specialists should provide Declarations of Conformity:
- at design stage (initial notice)
- at final stage (all details and changes declared), and
- for nozzle manufacturers, successful BS 8458 and BS 8663 fire tests.
Portable personal protection systems are not considered suitable means of satisfying the requirements of Standard 2.15. They may, however, be beneficial in some unique situations in existing dwellings to assist in the protection of vulnerable occupants.
Alternative approaches in a particular case may or may not be compensated by an automatic fire suppression system.
A sheltered housing complex is a purpose built complex comprising of 2 or more dwellings e.g. houses, flats and maisonettes, where the occupants are likely to receive a support service due to the nature of their vulnerability or need e.g. age, infirmity, disability, illness, mental disorder or are dependent on alcohol or drugs. Such occupants are likely to react slowly to the fire alarm (see Standard 2.11) and the suppression system may provide the additional time necessary to make a safe escape.
Therefore, a sheltered housing complex should have an automatic life safety fire suppression system designed and installed in accordance with BS 9251: 2014.
Research and fire statistics shows that occupants in flats and maisonettes would benefit from automatic fire suppression systems. Whilst fire statistics also show that fire spread beyond the dwelling of origin is a rare occurrence, fire dynamics suggest that any outbreak of fire through an external window or door opening is more likely to spread vertically than horizontally. Therefore, in order to protect occupants and to contain a fire in buildings containing flats and maisonettes, every flat and maisonette and any ancillary room should be provided with an automatic fire suppression system.
A fire sprinkler system in a flat or maisonette should be designed and installed in accordance with BS 9251: 2014.
Statistics indicate that there is a greater prevalence of fires in social housing dwellings. In order to help contain a fire and to protect occupants, every house, flat and maisonette that is a social housing dwelling should be fitted with an automatic fire suppression system. A fire sprinkler system in a social housing dwelling should be designed and installed in accordance with BS 9251: 2014.
A fire sprinkler system in a social housing dwelling should be designed and installed in accordance with BS 9251: 2014.
For a suppression system to be effective it is essential that there is an appropriate water supply. To assist the developer or designer in the initial stages of design, Scottish Water have produced a policy note on the installation of automatic fire suppression systems titled ‘Sprinkler systems for domestic and residential occupancies’. The policy note may be downloaded from the resource section of Scottish Water’s websiteHowever, there is still a need for developers and designers to discuss project specific details with Scottish Water to determine what supply is likely to be available and what pressure can be expected. It is recognised that pressures will vary during the day and night, over the year and perhaps in future years. Therefore, it is imperative that the system is designed on the basis of what the minimum pressure and flow is likely to be. If there is any doubt, a tank and pump arrangement should be used.
Therefore, it is strongly recommended that housing developers should consult Scottish Water and the suppression system contractor early in the design process. For example, benefit could be gained through economies of scale with the agreed provision of a communal water supply tank and pump(s).