BS_9251-2021.pdf

BS9251:2021BRITISH STANDARDPublishing and copyright informationThe BSI copyright notice displayed in this document indicates when the document was last issued.The British Standards Institution 2021Published by BSI Standards Limited 2021ISBN9780539067163ICS13.220.20The following BSI references relate to the work on this document:Committee reference FSH/18/2Draft for comment 20/30403871 DCAmendments/corrigenda issued since publicationDateText affectedO THE BRITISH STANDARDS INSTITUTION 2021-ALL RIGHTS RESERVEDBRITISH STANDARDBS9251:2021ContentsPageForewordiii0 Introduction11 Scope12 Normative references23 Terms and definitions3Figure 1-Height of top storey in building44 Preliminary work and consultation14.1 Initial considerations74.2 Consultation74.3 Category of system10Table 1-Category of system115 Design115.1General115.2System type125.3Design density and duration of supply12Table 2-Minimum design parameters135.4Extent of sprinkler protection145.5Classification of residential and non-residential occupancies14Table 3-Examples of classification of areas and design criteria for areas protected withResidentialBS EN 12259-14 sprinkler heads155.6 Ordinary hazard protected areas16Table 4-Examples of classification of areas and design criteria for areas to be protected withBS EN 12259-1 sprinkler heads175.7 Sprinkler coverage and positioning17Figure 2-Two examples of shadow areas(plan views)19Figure 3-Bay windows and similar features195.8 Ceiling pockets205.9 Residential pattern sprinkler heads205.10 Hydraulic calculations215.11 Water supplies21Figure 4-Stored water supply24Figure 5-Examples of water volumes for various shared water supplies26Figure 6-Typical shared pump and water supply with PDV275.12 Pumps28Figure 7-Typical power supply arrangement to sprinkler pump and ancillary equipment29Figure 8-Enhanced water supply32Figure 9-Examples of primary and secondary power supply configurations335.13 Pipes and fittings335.14 Flexible sprinkler connection345.15 Valves355.16 Pressure reducing valves355.17 Frost protection365.18 Sprinkler system fire and fault alarm functionality36Table 5-Fault conditions to be monitored in category 2,3 and 4 systems386 Installation,commissioning and documentation396.1 Installation396.2 Commissioning416.3 Documentation42THE BRITISH STANDARDS INSTITUTION 2021-ALL RIGHTS RESERVED IBRITISH STANDARDBS9251:2021ForewordPublishing informationThis British Standard is published by BSI Standards Limited,under licence from The BritishStandards Institution,and came into effect on 30 June 2021.It was prepared by SubcommitteeFSH/18/2,Sprinkler systems,under the authority of Technical Committee FSH/18,Fixed fire fightingsystems.A list of organizations represented on these committees can be obtained on request to theircommittee managers.SupersessionThis British Standard supersedes BS 9251:2014,which is withdrawn.Relationship with other publicationsReference is made in the publication to the advice on selection of fire protection systems set outin BS 5306-0.Attention is also drawn to the requirements of BS EN 806,with particular regard tobackflow prevention,to BS EN 805 where appropriate,and to BS 1710 for guidance on identificationand marking of pipework.Where pumps are provided,attention is drawn to the electrical supplyrequirements of BS 7671.Sprinkler protection for industrial premises and commercial buildings other than those listed inthis British Standard is specified in BS EN 12845.Where sprinklers are not installed primarilyfor life protection in domestic and residential occupancies,sprinkler installations conforming toBS EN 12845 might be more appropriate than those conforming to this British Standard.Guidance on the application of sprinkler systems is given in BS 5306-0,BS 9991 BS 9999,theBuilding Regulations 2010,Approved Document B for use in England 1,2,Wales 3,4and itsequivalents in Scotland 5,6and Northern Ireland Z.BS 9251 covers fire sprinkler systems for residential and domestic premises that are more than fourstoreys or above 18 m in height;additionally fixed residential fire sprinkler systems in buildings forresidential occupancies up to four storeys or 18 m in height,whichever are lower,are covered inBS EN 16925.FSH/18/2 has detailed their concerns about BS EN 16925 in the National Foreword forthat publication.Information about this documentThis is a full revision of the standard,and introduces the following principal changes.Introduction of a fourth category of system to cater for taller residential buildings(greater than18 m)and higher risk scenarios.The building height of over 18 m for a fourth category waschosen for the following reasons:to align with Fire and Rescue Service national operational guidance,which determinescapability,e.g.access and response time;for consistency with BS EN 16925;andgreater risk profile in higher rise buildings,including the need for improved resilience.Additional recommendations for larger capacity minimum water supplies for taller buildings andhigher risk scenarios.Further recommendations for duplicate pumps and other reliability enhancements incertain scenarios.OTHE BRITISH STANDARDS INSTITUTION 2021-ALL RIGHTS RESERVED III