Fire Safety Solutions

Our building regulations started with the Great Fire of London in 1666. Prior to this, no allowance was given to stopping the spread of fire from one house to the next and you could, with a bit of hindsight, see that the densely packed housing in London was an accident waiting to happen.

After the fire, the great men of the time, principally Christopher Wren and Robert Hooke, were charged with the rebuilding of London. Hooke was appointed Chief Surveyor the first building inspector - and is credited with the development of a code to ensure that no such calamity ever again befell London. The streets were rebuilt on a slightly wider plan and he introduced the concept of compartmentalising buildings so that fire could not easily spread between them.

To this day, Hookes legacy lives on. Look at any London terrace and notice how the party walls between houses protrude up through the roof line. Its a fiddly detail but it hinders fire moving along the roof of a terrace.

The Regulations

The fire regulations exist today embedded in the Building Regulations. In England and Wales, the fire regs are known as Part B. In Scotland and in Northern Ireland, the relevant section is Part E. They are much the same in all parts of the UK, but this focuses on the English and Welsh Part B, as this applies to the greatest number of self-builders.

• Scotlands regs can be viewed at sbsa.gov.uk
• Northern Irelands regs can be viewed at dfpni.gov.uk
• England and Wales regs can be viewed at odpm.gov.uk

As with so much of the Building Regulations at the moment, Part B is under review. The risks haven't changed a great deal but there is pressure to harmonise our requirements and standards with the rest of the EU. In fact, many of our fire safety requirements are significantly more exacting than our European neighbours but our actual fire-testing regimes are reckoned by many to be not quite so stringent.

Timber frame vs. Blockwork

Another feature of our fire regulations is that they emphasise the importance of saving life rather than property. They examine how long each element of a structure will withstand fire - 30 minutes is usually seen as a key time - but they have little interest in what happens to the property once fire has taken hold.

Not so the insurance companies, who have to pay for reinstatement. Insurance companies do sometimes penalise building systems that they think are more likely to be destroyed by fire. This has led to a number of claims that masonry construction is superior to timber frame because its both innately fireproof and has better fire ratings than framed building systems. It is not a distinction that the building regulations make. There is no evidence that individual timber framed houses are more of a risk than masonry-built ones. Indeed, timber actually performs very well in the early stages of fire: the material chars slowly. Steel, on the other hand, which is used widely in all building systems, is identified as a fire risk because it twists quite quickly when subjected to intense heat and, of course, it is often used to support openings and floors. The regulations give much closer consideration to steel elements than timber.

However, the effect of a major fire on any structure is often so severe, whatever the built system, that the reinstatement costs are not significantly different, whatever the structure.

The Individual Home

As a potential builder of a detached house, there are just a few occasions when you will be aware of the building regulations. Things are very much tighter for people building attached houses or flats, but for the sake of simplicity we will stay with detached housing.

Most commonly used building materials are adequate as far as fire safety is concerned. As many people now realise, the principle fire hazards in the home are soft furnishings, but this is not something of concern to the building regulations, which only look at fixed structures.

There is a requirement for walls and ceilings to be half-hour fire resistant, but you would be stretched to construct a wall or a ceiling that wouldnt meet this basic standard all that is required for a regular ceiling is 12.5mm plasterboard under floor joists. This doesn't build in fantastic levels of fireproofing but the idea of the regulations is to provide 30 minutes of evacuation time between the outbreak of fire and the breakthrough from one room to the next.

Doors

The situation with doors is even more relaxed. An open door provides no fire resistance at all: it can create drafts and turn a small fire into a large one surprisingly quickly. The single most effective fire prevention measure is to close all doors, but legislators realise that this is not realistic. There seems little point in insisting on high levels of fire resistance in walls and ceilings if the doors between the rooms are left open.

There are two main exceptions to this relaxed state of affairs. The integral garage and the third storey or loft conversion. Both require one-hour fire resistance on the separating ceilings (above in the case of the garage, below on the loft conversion), and both require the use of self-closing fire doors. The door between the garage and the main house has to be a fire door and additionally there has to be a step up from the garage into the house. This is to protect the house from any burning liquid that might spill out of a vehicle.

The situation on the third storey is more complicated. Here you have to have a fireproof enclosure down to ground level as a means of escape. This involves ensuring that the walls around the stairwell are half-hour fire resistant and that the doors opening onto this enclosure are half-hour fire doors. You also have to ensure that the route down to the ground floor exits close to the front door and not into a high-risk fire zone, such as a kitchen. If this is difficult, you will instead be required to provide a second means of escape via either an alternative internal staircase or an external fire escape.

Loft Conversions

Loft conversions are one of the principal areas of concern as far as the fire regulations are concerned, as you are introducing habitable space at a height where it is not practicable to escape in the event of a fire. Quite apart from the disruption of having to fit a new staircase, loft converters are often surprised that they are also required to upgrade the fireproofing on ceilings below the new rooms and on the walls of the stairwell down to the ground floor, not to mention adapting the existing bedroom doors into half-hour self-closing fire doors.

There are, however, a number of products available that make relatively light work of these fireproofing requirements. In particular, the development of intumescent paints and stains - which can be applied over existing surface finishes - has made it much easier to fireproof walls, ceilings and doors. These products work by expanding when they become hot, thus creating an insulating blanket over the surface.

Smoke Detectors

Another area where you will notice the effect of the fire regulations is in the provision of smoke detectors. These became mandatory in 1992 and, since then, all new homes have been required to have them, not just fitted, but mains operated with a battery back-up as a fail-safe.

Smoke detectors cost around £20 and can be wired into the houses lighting circuit. The requirement is that there should be smoke alarms on each storey and that they shouldn't be further than three metres from any bedroom door, so that some larger homes will require two or more on the upstairs landing.

What the regulations do not mention is the different types of smoke detector you can choose from. The cheapest and commonest are the ionisation detectors which are very sensitive to small particles of smoke produced by flaming fires, such as chip pans, and will detect this type of fire before the smoke gets too thick. But you can also specify optical ones, which are more effective at detecting larger particles of smoke produced by slow-burning fires, such as smouldering foam-filled upholstery and overheated PVCu wiring. Optical detectors are more prone to going off in error, however.

A third and possibly more useful detector is the heat sensor, which gets triggered when temperatures reach around 55°C. Fit one in the kitchen but not too near the cooker. Whatever you choose, they have to be interconnected so that when one is triggered, they all go into action. Some smoke alarms have additional capabilities, such as emergency lights and silence buttons to override false alarms.

Arguably, the introduction of smoke detectors has been the most effective fire-protection measure ever. It has rendered many existing fire-control measures redundant and there is currently a review under way to relax the rules regarding loft conversions and third storey accommodation. The requirement to fit self-closing fire doors in particular is under review as it is widely accepted as very unpopular - as is proved by the fact that many self-closing devices are frequently removed once building regulations approval has been won.

Egress Windows

Since 2002, there has been a requirement to have an escape window in all habitable rooms above ground floor. These are known as egress windows: the word egress is the opposite of access. Part B of the Building Regulations is specific about what constitutes an egress window:

• an openable area of not less than 0.33m²
• opening dimensions of at least 450mm wide x 450mm high
• an opening within 1,100mm of the floor
• with a sloping roof, the distance between cill and eaves should be no more than 1,700mm

For many windows, this doesn't present a problem but a few designs have trouble. Simulated sash windows, which open outwards, are not acceptable in their original format, neither are narrow windows with fixed vertical bars. However, they can be reconfigured, with a detail known as a flying mullion an opening casement with the vertical bar attached to the outer edge, rather than in the frame. When closed, it looks just like a normal casement window only when open does it look strange.

Boundaries

Another area that can cause problems is building close to a boundary using combustible materials: typically timber cladding or thatched roofs. The guideline is that if the walls consist of a large amount of combustible material, they must be at least six metres from the boundary. For roofs, the requirement is 12 metres.

There are ways round this. Cement board sidings, that look just like timber, are acceptable as an alternative. For thatched roofs, Building Control accepts a design called the Dorset model, which stipulates that rafters be covered with breathable sarking board and that a smoke alarm be fitted in the loft. The top of the chimney must be 1.8 metres above the thatched ridge, as chimneys are the predominant cause of thatch fires. Using this design, you should be able to build closer to the neighbours boundary. For info, call the Thatching Advisory Service (see right for contact details).

Security vs. Escape

There are inevitably two conflicting needs here: a) to keep a house secure from intruders, and b) to make it easy for residents to escape quickly in a fire. Generally speaking, the regulations seek to place safety above security. The two ways this manifests itself are in how main entrance doors and windows are secured. Generally, the main entrance door should be secured by a night latch as well as a key. The key should be used to obtain entry from outside but at night it should be possible to open the door from the inside without a key you dont want to be running around the house looking for your front door key.

For years windows were offered with key-operated locks. Since 2002, egress windows have been required in all habitable rooms above ground floor and what is the point in having an egress window in your bedroom if it is locked and you haven't got the key?

However, what if you have an adventurous child? An easily openable window presents another hazard altogether. Because of this, the regulations fight shy of insisting on having keyless windows. What seems to be happening is that the manufacturers are mostly offering egress windows with push-button locks and child-resistant release catches on the stays.

Protecting Steel

The enclosure of steel beams, such as those used when breaking through an existing wall to create an extension, is another area which can cause problems. Steel beams are vulnerable if there is a fire, especially as they are invariably used to structurally support walls and floors. They are conventionally enclosed in double sheets of plasterboard to provide one-hour fire resistance, but there are also intumescent paints available which achieve the same fire ratings.

Beyond the Regulations

Downlighters: One area that concerns some people not directly addressed by the building regulations is downlighters. The basic principle of fireproofing is to compartmentalise each room so that fire doesn't spread quickly. Cutting holes into ceilings for downlighters compromises this: it is said to reduce the fire resistance of a ceiling from around 30 minutes to just four. The regulations don't cover downlighters in individual homes but if you are concerned, consider either a fire-rated down-lighter, such as Snaplite, or fitting fire hoods over the downlighter (envirograf.com).

Electrical Sockets: Electrical socket boxes and light switches compromise the fire resistance of walls, especially timber or steel stud walls. In a fire, the steel faceplate screws quickly give way, the plastic faceplate melts and the fire exposes a route up through the hollow wall into the fabric of the house. You can specify fireproof electrical boxes or fit intumescent gaskets in conventional boxes that expand when hot.

Sprinklers: Fire regulations make no requirements to use sprinklers though they are sometimes accepted as an alternative method of compliance by building inspectors where it is difficult to provide adequate means of escape.

A typical system delivers water at around 60lts/minute (compared to 1,000lts/min from a fire hose). The ceiling-mounted heads are heat activated, usually set at 68°C. The guideline costs are around £15/m² or £200 per outlet. If you want one, you need a good supply from the mains: ensure you have a 32mm feed into house.

Further Reading:

• Ventilation: Your Options Explained
• A Guide to Heating & Plumbing
• Building Regulations