Active fire protection: What’s the best way to do it?

At the end of January, the Welsh assembly voted to make the installation of sprinkler systems mandatory in all new homes in Wales. The move was championed by assembly member Ann Jones and as well as getting cross-party support from the Welsh government, it was backed by Wales’ three fire services and the fire brigades union. In the coming weeks the Privy Council will decide if the Welsh assembly can turn the proposals into law.

Assuming it does, the rules could come into force within 12 months as a separate requirement to the Building Regs covering fire. It will make Wales the first part of the UK to demand active fire protection in all new homes. Currently under Part B of the Building Regulations sprinklers are generally only required in residential buildings more than 30m tall in England and Wales.

Ann Jones argues that sprinklers will improve safety and cut down on fire injuries and deaths. But she also claims that domestic fires cost the UK economy £7bn each year and that sprinklers could play a vital role in bringing this cost down.

The upside for specifiers is that it could mean a lot more freedom for design. According to Miller Hannah, head of Hoare Lea’s fire engineering group, the adoption of sprinklers presents the opportunity for more open-plan design and flexible layouts.

The Chief Fire Officers Association has now commissioned research from Swansea University to explore the effectiveness of fire sprinkler systems in preventing loss of life, injury and property damage.

However, the case for installing sprinklers isn’t clear cut. A detailed BRE study published in 2006 that involved extensive testing demonstrated that sprinklers are not necessarily the best solution for most housing. It concluded that smoke alarms, fitted in the room of fire origin, typically responded in half the time it took sprinklers and well before the conditions had become life threatening.

Gerald Jones, business manager at smoke alarm manufacturer Kidde, says a much simpler solution to cutting fire deaths and injuries for a negligible cost is to address the discrepancy between Building Regulations Part B and the code of practice for domestic fire alarm systems, BS 5839-6: 2004.

Currently, Part B requires smoke alarms only in corridors and heat alarms in some kitchens. According to the Code of Practice this might not prevent death or serious injury of occupants in the room where the fire originates. BS 5839-6, which applies to new and existing dwellings, recommends hard-wired and interconnected smoke or heat alarms in living rooms and a heat alarm in every kitchen as well as the usual smoke alarms in circulation areas.

There have also been proposals for an additional smoke alarm to be installed in the main bedroom to wake sleeping occupants in a fire.

Gerald Jones says: “For the negligible cost of installing two or three additional hard-wired alarms during construction, our homes could have in-built, comprehensive fire safety. And it’s still not too late to alter the current Welsh assembly proposals for sprinkler systems to add in these far more realistic measures.”

So could we see something similar adopted in England? Last month the communities department published a report looking at the cost of installing sprinklers in new-build domestic properties and whether this could be justified by the reduction in risk they provide. It was prompted in part by the Thames Gateway redevelopment, which could see 160,000 new homes built in the region by 2016. One of the aims was to look for evidence that the planning authorities should consider sprinklers beyond the requirements of the current Building Regulations, given the high proportion of social housing in this area – there are 50-150% more fires in social housing than the average across all housing types.

NERA Economic Consulting, which carried out the study, looked at the lifecycle cost of a number of scenarios against a baseline of “doing nothing”. It found that the benefits of installing sprinklers in all new housing in terms of reduced fatalities, injuries and property loss, fell short of the additional costs and that it did not support the mandatory installation of sprinklers in all housing or social housing in the Thames Gateway.

A private member’s bill to amend the Building Regulations to make it a requirement that new residential premises are built with automatic fire suppression systems is awaiting a third reading in the House of Lords. It hasn’t had overwhelming support, but don’t rule it out.

Alternative systems

Mist systems This is a type of sprinkler system that issues water as a mist and simply suffocates a fire. This system uses less water and as a result is less damaging to the space. However, there is a cost premium for this. The storage tank for a Mist system is a maximum of 1m3 which is a major space saving. The pipework is also much smaller – generally only 15mm in diameter. The Mist system is under review by the insurance industry.

Homesafe With Homesafe’s Greenflow system, the sprinkler heads are served by the same domestic cold water pipework serving the household plumbing fixtures. This eliminates the risk of water stagnating in the pipes and reassures the occupants that there remains a supply of water to each sprinkler head. It also means you do not need a dedicated sprinkler riser, which can be a significant cost saving.

Design requirements for sprinkler systems

Under Part B of the Building Regulations, residential sprinklers are only generally required within individual flats in developments over 30m in height. For specifiers there are a number of considerations to bear in mind. Floor to floor heights may need to be increased to cater for the sprinkler pipework. Minimum void depths would typically be 150mm within apartments and 250mm within common areas. Generally a water storage tank of about 10m3 will be enough to supply a conventional system, but this can be combined with the domestic water supply and should be sufficient for most buildings of up to 30m.

Ground floor access to the pumps and generators will be required for the fire brigade. A single pump is fine for properties up to 45m in height, but above this a multi-stage pump is required. A sprinkler tank room is required and this can usually be located within the basement though bear in mind that additional riser space may be required.

It is possible to conceal the heads using a flat plate. Alternatively exposed versions are available using a flush pendant or a drop down arrangement.

Individual zone valves should be provided for each apartment. Although this is not a requirement, it allows the fire brigade greater flexibility to switch off an apartment after an incident while protecting the rest of the building.

Original print headline - Would a sprinkler have prevented this?