Fire Safety Explained

The Building Regulations are large and complex. But it’s surprising how often they can be reduced to a few wellworn phrases and memos. And the fire regulations are a particularly good example of this. For rather than having to pay an inordinate amount of time trying to satisfy every aspect of the 80-odd pages of guidance, most designers have only to be aware of a few key points. This is no guarantee that your project won’t run into fire-related issues elsewhere, but these are specialised concerns that would normally be raised by your building inspector.

First point to note is that the UK has three separate building regulation territories: England and Wales (where the fire regulations are known as Part B), Scotland (Domestic 2 Fire) and Northern Ireland (Technical Booklet E). All these are downloadable for free. They are generally very similar, though often changes are made in one territory before being implemented in others. For simplicity’s sake, we will be looking at the regulations for England and Wales here.

As a rule, you don’t have to worry about the fire standards of modern housebuilding techniques, as they all tend to comply with the basics. The key point to understand is that everything should be designed to hold a fire for 30 minutes, which is deemed to be enough time to allow people to escape from a house. Even the flimsiest plasterboard on a stud wall room divider meets this requirement, so frankly nothing you are likely to want to build a house out of is likely to cause you any problems — though a Japanese paper screen might!

However, where you have connected dwellings – e.g. flats and terraces – there are much stricter guidelines about party walls and floors, and these elements have to be fire-proofed to a higher standard.

New homes require mains-operated (with battery back-up) smoke detectors. This guideline used to be easily met by having a detector on each floor, but this was upgraded in 2006 to meet a higher standard, set out in BS5839, which calls for detectors in kitchens and lounges as well.

There are three kinds of detector. The cheapest one is the ionisation type which gets fitted into the great bulk of stairwells and hallways; it picks up small (non-visible) smoke particles and is prone to springing false alarms if situated right next to the kitchen door. In kitchens, you really need to avoid smoke detectors and fit a heat detector instead, whereas in living rooms, especially those with an open fire or a stove, you are probably best off with an optical detector. So a typical BS5839 installation would involve using all three types of detector.

Bedrooms need to be provided with a means of escape or egress window. This is quite tightly defined as one with an opening not less than 0.33m2, a minimum of 450mm high and 450mm wide, and the opening should be no more than 1.1m above the internal floor. Most British window manufacturers have taken these requirements on board and now only produce egress-style bedroom windows, but this doesn’t hold for manufacturers of imported windows, so check that your bedroom windows qualify as egress windows before ordering.

The fire regulations now accept the use of sprinklers as a method of containing fires. Whilst sprinklers are unlikely to become mandatory in the foreseeable future, there are instances where installing them will enable you to undertake works which might otherwise fall foul of the regulations. This is particularly useful when undertaking renovations of large open plan structures like barns and chapels.

Integral garages have to be separated from the house for fire purposes. You have to fit a fire door between the house and the garage; the walls and ceilings have to be double boarded and you must have either a step or an in-built slope in the garage floor to reduce the risk of fire spread.

Unusual Materials

The type of material your house is built from will determine which regulations you have to comply with. There are some surprisingly strict requirements on minimum distances between dwellings if you use combustible materials on your roof or external walls. Use thatch or shingles on your roof and you have a minimum requirement to be 6m from the boundary; timber walling materials are also affected, but the rules are more complex.

Loft Conversions and Third Storeys

If you build a third storey (defined as being one more than 4.5m above ground level), you encounter another raft of means of escape issues. Essentially, you have to provide what is called a protected stairwell: this means that the walls around the stairwell have to have a higher fire rating than normal (a more expensive plasterboard) and the doors opening onto it have to be fire doors. Interestingly, the requirement to have self-closers on these fire doors has been removed, because it was unpopular and deemed to be unenforceable.

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