The LWF Blog
The case for residential sprinkler installation in the U.K.July 10, 2014 11:43 am
Sprinkler systems in residential premises such as blocks of flats and those buildings which have multiple-occupancy, such as complexes for retired persons, have been a rarity until fairly recently in the UK. It is a form of fire suppression most commonly seen in commercial buildings, where they are used to great effect to minimise fire damage and reduce fire growth. The inclusion of a sprinkler system in a residential build project would be subject to its own analysis, but consideration might be given to the information available. Current Building Regulations require sprinkler systems in higher risk (usually based on size/height) residential buildings.
What is a sprinkler system?
A sprinkler system can be defined as a series of pipes and sprinkler heads that is intended to spray water over a fire with the objective of controlling and suppressing it.
Back in 2004, the Office of the Deputy Prime Minister commissioned a cost/risk-benefit study entitled ‘The effectiveness of Sprinklers in Residential Premises’ which examined various scenarios where fire might occur in residential premises and looked at the differences in result in those cases where sprinkler systems were installed.
The main findings of that project, as stated in the Executive Summary are as follows;
• For the majority of scenarios experimentally studied, the addition of residential
sprinkler protection proved effective in potentially reducing casualties in the room
of fire origin and connected spaces
• Sprinkler protection was not found to be a complete panacea, slow growing and
shielded fires can be a problem
• Smoke alarms, fitted in the room of fire origin, responded typically in half the time
required by sprinklers and well before the conditions had become life threatening
• Closing the door to the room of fire origin, was found to be effective in keeping
tenable conditions in connecting spaces
• Residential sprinklers are probably cost-effective for residential care homes (old
persons, children’s and disabled persons care homes)
• Residential sprinklers are probably cost effective for tall blocks of flats (eleven
storeys and above)
• Residential sprinklers are not cost-effective for other dwellings
• In order for sprinklers to become cost-effective, high risk buildings may be
targeted, and justified on a case-by-case basis using the cost-benefit approach
developed in this project
• In order to be cost effective in a broader range of dwellings, installation and
maintenance costs must be minimal, and/or trade-offs may be provided to
reduce costs by indirect means.
• In general, the cost benefit conclusions from other countries’ experiences were
the same as this project, i.e. that sprinklers were not cost-effective, unless
systems were low-cost or trade-offs could reduce costs.
The cost-effectiveness of the installation of sprinkler systems will be subject to change, of course, and it may be that this element of the equation has changed since the project and report were issued in 2004. In any case, a cost/risk-benefit analysis should be undertaken for each project individually.
What does installation of a sprinkler system involve?
Installing a residential sprinkler system is less complex than putting in a plumbing system. The materials used for the pipes can vary from PVC to copper. An average sized room (15m2) only requires two sprinkler heads to ensure an adequate level of protection.
Today’s levels of research and technology mean that sprinkler heads and pipes can blend into the décor of the premises. They can be installed in the ceiling and walls, and the sprinkler heads can remain hidden in the ceiling until needed to operate.
The water pressure required for a sprinkler system is surprisingly low, as it acts when the fire is still small. The system can usually be directly connected to the domestic water supply, with no need for extra water supplies or pumps. There will be some instances when the water supply provisions are poor, and cannot be used to supply the sprinkler system. In such cases, additional equipment such as pumps and water tanks may be necessary.
How do sprinkler systems operate?
Residential sprinklers operate on a head-by-head basis, triggered by the heat released from the fire. Each sprinkler head contains a fusible link that will activate at temperatures typically ranging from 57oC to 79oC. Once operated, the system reduces:
• The temperature of the fire and surrounding area
• The size of the fire
• The production of smoke and toxic fumes
The residential sprinkler system can, as an additional safety feature, activate the premises’ fire alarm system (should it be fitted with a means of warning), alerting occupants in other rooms.
Accidental water discharge is a possibility when installing any type of sprinkler system. But past experience has shown that the probability of accidental discharge of an adequately installed and maintained residential sprinkler system is very low.
What about maintenance of a sprinkler system?
The point has been made a number of times that homeowners and building managers will be incapable of adequately maintaining a residential sprinkler system, which is very similar to a central heating system, but less complex. The problem for homeowners and building managers is therefore similar to arranging servicing for their central heating pipes and boilers.
The water in a residential sprinkler system is static in the pipes, so there is a possibility of freezing in the winter. This problem can be avoided if the system has been properly installed and suitably lagged to recognised standards.
Next week’s blog will continue on the subject of sprinklers in residential premises and will look the benefits of sprinklers in more detail. In the meantime, if you have any queries about sprinklers, fire protection or fire engineering, please contact Peter Gyere on 020 8668 8663.
Lawrence Webster Forrest Limited is a fire engineering and fire risk management consultancy, with over twenty years’ experience in the development of fire engineered technology and the application of fire safety standards including fire engineered techniques.