To explain the thinking behind specifying a fire sprinkler system in the design. Sprinkler systems are common in commercial/industrial premises, and in other countries they are used in residential too - but not (yet) here in the UK. They're actually very simple - a tank with pump constantly "primed", and heads that open at high heat. False discharges are almost non-existent, and only the head(s) in the room where the fire is will open - not, as is commonly thought, the whole system. There's no complex electronic control or detection required. So they are effective and localised. The Building Regulations now acknowledge, since the 2006 edition, the validity of sprinkler systems to contribute to fire safety in residential buildings.
The Withington Co-operative Eco-house is going to be occupied by a group of six people (the co-operative part of the project is just as important as the eco-house part, but that's another story). The traditional approach to fire safety in shared accommodation (what are known in this field as HMOs) has been to treat the hall/stairs/landing area as a "protected" escape route, achieved by replacing all the doors with fire doors. The recommended measures in the LACORS official guidance on the subject  for a shared-house HMO of three storeys stops short of full fire compartmentation, providing that the building is "of sound traditional construction" (which ours is). And, as it happens, the Building Regulations guidance for fire safety treats an HMO of up to six occupants in the same way as a normal house anyway, which gives some flexibility in how we approach fire safety in the design of this project. Confused? Well that'd hardly be surprising, since fire safety in rental housing is covered by multiple overlapping and sometimes contradictory regulatory systems!
I'd personally argue that the fire risk in co-operative shared housing is lower than in your normal HMO situation (that argument is not gone into here for reasons of space). What we're trying to do here is provide a best-practice model. So why not go with the accepted wisdom of fire doors? Well, I think that's not the best idea for three reasons:
- The house still has its original "period" doors (although the panels have been hardboarded over - typical 1960s style). When restored, these will contribute aesthetically to the living environment we're creating in the building, helping it to feel more homely. This is particularly important for us as we're offering co-operative living as a viable alternative way of creating a home, not just a stepping-stone place to live until people move on elsewhere - as often occurs in student-type HMO properties. (On a related note, the LACORS guidance acknowledges the disadvantage of escape route signage: "The need for clear information should be balanced with the desire to maintain a homely environment. The excessive provision of signage can create an ‘institutional’ feel to a building, which is undesirable in premises which are people’s homes". So I'd argue this approach should be applied to doors too.)
- For fire doors to be of any use at all, they need to be closed. In non-residential buildings this is achieved by fitting a self-closing device (either a box with an armature, mounted at the top of the door, or a concealed system within the hinges). This approach was previously specified in the Building Regulations, however it was found that too often occupants disabled the closers and/or propped the doors open, because having doors closing all the time was too intrusive in a domestic environment. Consequently the Building Regulations now state "Other than doors between a dwellinghouse and integral garage, fire doors need not be provided with self-closing devices". Thus the effectiveness of the whole fire-door approach could be compromised by the occupants of the building not ensuring the doors are closed; in other words, fire doors aren't a good solution for domestic situations anyway.
- With high degrees of insulation and draft-proofing in eco-houses, a supply of fresh air and the movement of air around the building becomes a design issue; no longer can it just be assumed to occur ("ventilation by accident"). Whilst it's a reasonable assumption that people will close their bedroom doors when asleep, having doors open throughout the house during the daytime will encourage through ventilation and make it less likely that occupants will suffer from stale air in certain rooms.
So the design approach taken with this project is as follows:
- A sprinkler fire suppression system is installed throughout the building. Instead of a fire being confined to a particular compartment within the building, the sprinkler system will actually put the fire out before it has a chance to spread. This greatly reduces the chances of occupants being trapped within the building because a fire has spread. However, there is still a danger from smoke (especially for sleeping occupants).
- A full fire alarm system will be installed throughout the building, which will be integrated with the sprinkler system and smoke control system (what is known as a Grade A LD1 system). With detector heads in every room and sounders positioned so that the alarm can be heard throughout the building, occupants will be given the earliest possible warning of fire, giving the most time to escape. Although it's likely that a fire would trigger a smoke detector first, the fire alarm will also be integrated with the sprinkler system, so that release of water from the system sounds the alarm. The alarm will also be able to be activated through manual call points.
- The escape route is down the stairs and out the front door. To protect this area from smoke, an electromechanically operated skylight window (supplied by Velux) will be installed at the top of the stairwell, which will be integrated into the fire alarm, so that the presence of smoke anywhere in the building will trigger the window being opened to evacuate the smoke from the escape route.
To my mind, it makes far more sense to deal with a fire by actually putting it out, rather than letting it burn until the fire brigade arrive. This design was approved by Building Control, as part of our full plans submission. It will be interesting to see how it is viewed elsewhere.
1. LACORS Housing - Fire Safety guidance, August 2008
2. Building Regulations Approved Document B, volume 1 (2010 edition)