While undoubtedly they make our homes safer, the cost of sprinkler systems means they are dismissed by most self builders.
However, Wales has broken ranks with the rest of the UK and passed legislation requiring all new properties to be protected by sprinklers. And there is every likelihood that other parts of the UK will follow suit.
Why Bother with Sprinklers?
The short answer is that they save lives. Sprinklers also reduce the number of serious burns and injury cases, and the amount of damage caused by house fires. The latest research from the American National Fire Protection Association shows that the death-per-fire rate is dramatically reduced when sprinklers are present, and that property damage is reduced from an average of $17,000 per fire down to $4,000. Furthermore, when sprinklers are installed, subsequent fires are almost always contained in one room, whereas in homes without sprinklers, it spreads to other rooms in 75% of cases. Firefighters take time to arrive after a fire has started and end up using far more water to put out the fire, which itself causes damage — so sprinklers actually work to reduce the risk to lives and property.
Other Fire Measures
While sprinklers are not currently a requirement in new homes, there are other measures in place to ensure fire safety. Most standard materials are adequate as far as the Building Regulations are concerned, but there is a requirement for walls and ceilings to be half-hour fire resistant, while integral garages, third storeys and loft conversions need one-hour fire doors which are self-closing. Smoke detectors are mandatory and there must be an escape window (egress window) in all habitable rooms above ground floor. Outside, there has to be appropriate access for a fire engine. For more detailed requirements, view the Building Regulations Part B Fire Safety at planningportal.gov.uk
How Do They Work?
Fire sprinklers are only activated when the temperature in the room in which a fire is burning exceeds the preset temperature of the sprinkler head — nominally 68°C. Sprinklers operate as individual heat sensors, meaning that water is only released in the area where there is a fire. They are not activated by smoke. Often in a room with two sprinkler heads, only one operates. Sprinklers typically deliver 60lts/minute (compared to 1,000lts/min from a fire hose); systems are usually plumbed with copper pipe or rigid cPVC pipe, fed off the rising main. Ideally, they require a 32mm cold feed into the house, as the systems need a good flow. This can be integrated with a rainwater recycling system.
The typical area covered by each sprinkler head is 15m2, so only the largest rooms would require more than one outlet.
Sprinkler outlets are actually very discreet — about as intrusive as a downlight. They tend to be concealed fittings, so all you will see in the house is a series of 100mm white discs, protruding slightly down below the ceiling level, as on this pictured barn conversion. Only large rooms (bigger than 15m2) would need more than one sprinkler. Like any plumbing system, the pipework is installed within the building fabric and the only visible component is the sprinkler head itself.
Are There Any Issues?
There are numerous objections to enforcing the uptake of sprinkler systems. Unsurprisingly, the main ones are connected with the costs involved. New housebuilding is already incredibly expensive and it’s constantly being loaded down with additional costs being imposed by Government regulations — insulation, acoustical works, safety glass, thermostatic taps, disabled access requirements, etc. And Part B of the existing Building Regulations already calls for the use of smoke detectors and various passive fire protection measures, which have been extremely effective in reducing the number of fatalities and injuries.
Whilst no one would argue that sprinklers aren’t a good solution for certain designs (such as open plan areas and loft platforms), there is a widespread feeling that the wholesale adoption of sprinklers is akin to using a very expensive sledgehammer to crack a small nut. Newly built homes are inherently much less at risk from fire damage than most of the existing housing stock, and there is a feeling that adding 2-3% to their build cost in order to make them safer still is focusing resources in the wrong area.
There are also worries about sprinkler systems malfunctioning. Although industry literature suggests this is unlikely: “Data collected over 30 years suggests that the chances of a sprinkler head malfunctioning are estimated to be extremely remote, perhaps no more than 1 in 16 million.” Whilst this may appear to be an unlikely possibility, it doubtless doesn’t account for cases where systems are triggered by malicious tampering or accidental damage.
There are also construction-related issues to consider. A sprinkler system requires a 125mm-deep ceiling cavity, which is easier to incorporate into some designs than others. Solid floor and ceiling systems (pre-cast concrete; SIPs) already work with added service voids, but these are typically less than 50mm deep. Having to widen these voids to 125mm would make their use unviable in many cases. To be fair, there are often ways around these issues: sprinklers can be ducted through walls and set to release sideways if ceiling location is difficult. One solution may be to install a partial system, though the cost saving may not be pro rata.
If you choose to install a domestic sprinkler system in your new home, do ensure that the company you employ is working to the industry standard (BS9251) and is preferably FIRAS accredited.
What will it cost?
In a new dwelling, the cost works out at around £15 to £20/m2, or around £200 per outlet. That’s equivalent to approximately £3,000 to cover every room in a four bedroom house. In addition to this, there are the costs of an annual maintenance contract. However, the use of sprinklers can reduce costs elsewhere, especially where there are expensive fire doors to be installed instead.