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Welcome to the Plumis fire protection blog. Stay informed about domestic fire safety, fire building regulations and ADB-compliant solutions for open plan living. Please feel free to browse through the posts and comment about what you read.

Thursday, 5 April 2012

Dummy Walls: Dumb Idea!

A clumsy approach to meeting building regulations in loft conversions has led to a dangerous phenomenon – the dummy wall. William Makant explains the problem and proposes a safe and legal route to open plan layouts.

With sluggish property markets, loft conversions have grown popular: they add value without the high legal, stamp duty and agent’s costs of a house move. But in many cases householders and builders collude to work around fire safety regulations with an illegal, makeshift construction: the dummy wall.


Building regulations propose a protected escape route when a loft conversion is added to a two-storey property, to allow people on upper floors to escape at ground level, or from first floor windows, without exposure to smoke and heat from a lounge/kitchen fire. By keeping conditions tenable on this exit route while a fire rages downstairs, lives are saved.

A protected escape route is theoretically a powerful way to save lives. Unfortunately, the reality is imperfect. Householders want light, open living spaces and often prop fire doors open, compromising the ideal of protection by compartmentation
. The problem does not end here however; consumers trends are towards open plan layouts with greatly reduced compartmentation.

UK regulations allow the use of fire suppression options like sprinklers to compensate for a layout with poor compartmentation, but most projects in practice do not follow this route. Instead, many homeowners opt for the cheap solution: create a protected corridor, have Building Control sign it off, and remove this “dummy wall” shortly afterwards. Bizarrely, legislation intended to improve fire safety actually leaves all parties uncomfortable with the outcome and the process used to reach it:
Homeowners skirt the law, pay for pointless temporary changes to their home, and enjoy poor fire safety in the interim;
  • Loft converters risk their reputation;
  • And those responsible for fire safety have unknowingly failed to meet their goals.

Construction and removal of the dummy wall poses a serious threat to safety. BRE ran a large suite of tests representing television fires in loft converted houses, which found that:
  • Conditions in the room of origin (lounge) always became lethal after 20 minutes.
  • With the lounge isolated by a closed door, tenable conditions were maintained throughout the rest of the house.
  • With the lounge door open or an open plan layout, conditions also became lethal in all other open spaces of the house.
  • Sprinklers in the lounge restored survivable conditions throughout the rest of the house.
  • The life safety benefits of linked smoke alarms were clearly demonstrated.

Despite the finding that either compartmentation or suppression is key to survival, fire doors are very often propped open and are not required to feature spring closers. Even in conventional closed plan layouts, the compartmentation ideal is no longer realistic; doubly so for homes with open plan layouts or dummy walls.


A study by the NHBC Foundation confirms that interlinked alarms and active fire suppression in an open plan layout is just as safe as an equivalent unsuppressed closed plan layout.

With fire suppression emerging as a legal and safe way to implement open plan layouts, and with sprinklers often claimed to cost as little as £1500, why aren’t sprinklers a standard solution in loft conversions, competing more effectively with dummy walls"

Sprinklers were originally designed for large business spaces where the setup cost is justifiable in insurance savings alone. In UK homes by contrast, the project size is smaller; low mains pressure and high flow requirements (perhaps 100lpm) can mean substantial cost and complexity in the form of pumps, tanks, and supply upgrades. The resultant cost and uncertainty makes householders uncomfortable; the simple and consistent, but deadly, dummy wall, much less so.

The situation is changing as more convenient and
cost-effective alternatives to sprinklers emerge; these solutions can meet building regulations as long as they are backed by evidence. To quote ADB:

“ 0.18 There are many alternative or innovative fire suppression systems available. Where these are used it is necessary to ensure that such systems have been designed and tested for use in domestic buildings and is fit for their intended purpose”

An example of these alternatives is Automist, a high-pressure mist device which mounts around the kitchen sink or on a wall. In the event of a fire, a heat alarm is triggered at 57°C and a high pressure pump powers just 5lpm of water as a fine mist throughout the volume to be protected. The cost effectiveness of such systems is achieved by being provided as a complete “ready to install” pre-engineered kit which will protect small volumes, such as the open plan lounge of a home.











Putting Automist in an open plan loft conversion offers much more than comparable costs to dummy walls: it solves the regulatory problem permanently and also provides permanent fire safety to occupants. It’s time to replace the dumb idea with a no-brainer!

For further information on the Plumis Automist range of water-mist suppression solutions call Plumis on 020 8133 8775, visit
www.plumis.co.uk or email info@plumis.co.uk


The NHBC Foundation Report NF19 finds that hallway doors are open 80% of the time by day and 60% of the time by night: