[
Low cost sprinkler systems can, on paper at least, be effective in reducing death and injury in homes. But the performance of such systems can depend on the vagaries of domestic water supplies, as a study just published illustrates.
The research, carried out by the Fire Protection Association, while acknowledging the positive effects of smoke alarms on life safety, says they are unlikely on their own to realise significant further reductions in deaths. Sprinkler systems, on the other hand, are not commonplace in dwellings in the UK, being limited by cost considerations and market forces, and are currently largely confined to high risk residential premises and prestigious or historically important homes.
Sprinkler systems that are designed to established standards are technically robust, but may not be capable of implementation at a price to enable widespread use. The research was based on the assumption that some degradation in performance of systems may be tolerated if they are capable of having a sufficient impact on fire deaths. The FPA was therefore asked to:
– Review existing work, standards, systems and experience abroad
– Undertake a survey of water supply companies to establish mains water pressures and supplies
– Analyse fires in the home
– Design a low-cost residential fire suppression system for the UK housing sector
– Assess the hydraulic performance of the developed system and refine it where necessary
– Conduct realistic fire trials to assess the effectiveness of the system.
Prototype system
A prototype system was developed, based on the BRANZ model, which offers the potential to reduce fire deaths in UK dwellings at costs lower than that for traditional domestic sprinkler systems. The cost savings result from combining the domestic water and sprinkler pipe distribution networks. This obviates the need for some expensive high-maintenance equipment and relies on town mains pressure, rather than an installed pump. Inherent in the design is upgrading the water supply pipe from the mains to a 32mm pipe, although in some areas pre-existing 25mm connections may be suitable.
The researchers analysed fire injury statistics and water supply data and showed that a system requiring 60 l/min of water has the potential to be installed in 60% to 75% of the UK housing stock. As such, these systems have potential to save between 166 and 208 lives and mitigate between 3500 and 4400 injuries a year (assuming installation in all suitable properties, both new and existing, although no implementation mechanisms currently exist). These figures, however, are based on a number of significant assumptions which, the report says, will need to be tested in future work programmes, and represent the upper limit of injury reductions.
Estimated system installation costs for a single property range from GB pound 2080 for a fully furnished house, GB pound 1050 for a gutted property, to GB pound 480 for a new build (further savings would be available for bulk installations). A significant proportion of the cost (40% to 60% ) of retro-fitting such systems in existing properties arises from the installation of a new water supply pipe and mains connection. While this is likely to be cost beneficial for new build properties, it is probable that specific ‘higher risk’ groups would need to be targeted for cost-benefits to arise for retrofitted systems.
These estimates also assume performance to established domestic sprinkler designs which is unlikely, due to the some aspects of the design. Many other assumptions were also made and the authors of the report stress that it should be read in full and understood – before the figures are used to support any case.
Future work should concentrate on improving the quality of data appropriate to the model. This could be best achieved by considering smaller regions so that local variation in building design, fire statistics and water supplies can be more accurately considered. A number of options exist, one of which might be to consider each of the UK’s major cities in isolation. In that situation, the identification of quality local information and engagement of key stakeholders would be easier. The provision of quality temporal water pressure supply information by survey or experiment is paramount to the success of this: mean data is insufficient if the ‘effectiveness’ of the system is to be properly appreciated.
Water supplies
Consideration also needs to be given to the Water supplies
limitations of the current system design, which is restricted to properties of two storeys or less, has an un-quantified impact from fluctuating water pressures, and has no system maintenance. and to the provision of guidance for designing and installing lower cost sprinkler systems. An accreditation scheme for plumbers may also need to be developed, concludes the research.
The main risk associated with a large scale roll-out of the system is the lack of control over water supplies. While every effort was made in the design to make the most of available water pressures, the minimum service supply pressures that water authorities must achieve are well below that required by the system. Although most water authorities deliver well in excess of this minimum, the maintenance of supply pressures is often performed only in accordance with demand. At times of low usage, pressures may be lowered to reduce loss through leakage.
The potential for a roll-out of this, and other fire suppression systems, could be improved if consideration was given to modifying current practice to improve the performance of water supply connections. Such an approach may have far reaching implications for innovation and flexibility in other areas of fire protection for dwellings, the research concludes.
Development of a lower-cost sprinkler system for domestic premises in the UK Fire Research Technical Report 2/2007 is available at: www.communities.gov.uk
[
Low cost sprinkler systems can, on paper at least, be effective in reducing death and injury in homes. But the performance of such systems can depend on the vagaries of domestic water supplies, as a study just published illustrates.
The research, carried out by the Fire Protection Association, while acknowledging the positive effects of smoke alarms on life safety, says they are unlikely on their own to realise significant further reductions in deaths. Sprinkler systems, on the other hand, are not commonplace in dwellings in the UK, being limited by cost considerations and market forces, and are currently largely confined to high risk residential premises and prestigious or historically important homes.
Sprinkler systems that are designed to established standards are technically robust, but may not be capable of implementation at a price to enable widespread use. The research was based on the assumption that some degradation in performance of systems may be tolerated if they are capable of having a sufficient impact on fire deaths. The FPA was therefore asked to:
• Review existing work, standards, systems and experience abroad
• Undertake a survey of water supply companies to establish mains water pressures and supplies
• Analyse fires in the home
• Design a low-cost residential fire suppression system for the UK housing sector
• Assess the hydraulic performance of the developed system and refine it where necessary
• Conduct realistic fire trials to assess the effectiveness of the system.
Prototype system
A prototype system was developed, based on the BRANZ model, which offers the potential to reduce fire deaths in UK dwellings at costs lower than that for traditional domestic sprinkler systems. The cost savings result from combining the domestic water and sprinkler pipe distribution networks. This obviates the need for some expensive high-maintenance equipment and relies on town mains pressure, rather than an installed pump. Inherent in the design is upgrading the water supply pipe from the mains to a 32mm pipe, although in some areas pre-existing 25mm connections may be suitable.
The researchers analysed fire injury statistics and water supply data and showed that a system requiring 60 l/min of water has the potential to be installed in 60% to 75% of the UK housing stock. As such, these systems have potential to save between 166 and 208 lives and mitigate between 3500 and 4400 injuries a year (assuming installation in all suitable properties, both new and existing, although no implementation mechanisms currently exist). These figures, however, are based on a number of significant assumptions which, the report says, will need to be tested in future work programmes, and represent the upper limit of injury reductions.
Estimated system installation costs for a single property range from £2080 for a fully furnished house, £1050 for a gutted property, to £480 for a new build (further savings would be available for bulk installations). A significant proportion of the cost (40% to 60% ) of retro-fitting such systems in existing properties arises from the installation of a new water supply pipe and mains connection. While this is likely to be cost beneficial for new build properties, it is probable that specific ‘higher risk’ groups would need to be targeted for cost-benefits to arise for retrofitted systems.
These estimates also assume performance to established domestic sprinkler designs which is unlikely, due to the some aspects of the design. Many other assumptions were also made and the authors of the report stress that it should be read in full and understood – before the figures are used to support any case.
Future work should concentrate on improving the quality of data appropriate to the model. This could be best achieved by considering smaller regions so that local variation in building design, fire statistics and water supplies can be more accurately considered. A number of options exist, one of which might be to consider each of the UK’s major cities in isolation. In that situation, the identification of quality local information and engagement of key stakeholders would be easier. The provision of quality temporal water pressure supply information by survey or experiment is paramount to the success of this: mean data is insufficient if the ‘effectiveness’ of the system is to be properly appreciated.
Water supplies
Consideration also needs to be given to the Water supplies
limitations of the current system design, which is restricted to properties of two storeys or less, has an un-quantified impact from fluctuating water pressures, and has no system maintenance. and to the provision of guidance for designing and installing lower cost sprinkler systems. An accreditation scheme for plumbers may also need to be developed, concludes the research.
The main risk associated with a large scale roll-out of the system is the lack of control over water supplies. While every effort was made in the design to make the most of available water pressures, the minimum service supply pressures that water authorities must achieve are well below that required by the system. Although most water authorities deliver well in excess of this minimum, the maintenance of supply pressures is often performed only in accordance with demand. At times of low usage, pressures may be lowered to reduce loss through leakage.
The potential for a roll-out of this, and other fire suppression systems, could be improved if consideration was given to modifying current practice to improve the performance of water supply connections. Such an approach may have far reaching implications for innovation and flexibility in other areas of fire protection for dwellings, the research concludes.
Development of a lower-cost sprinkler system for domestic premises in the UK Fire Research Technical Report 2/2007 is available at: www.communities.gov.uk