THE PROPOSED CHANGES HAVE SIGNIFICANT COST IMPLICATIONS
The ODPM is seeking the construction industry's response to its proposals for updating Approved Document B to the Building Regulations for Fire Safety in Buildings, in England and Wales.
The proposed changes range from clarifications of the existing document, to changes with significant effects on building design.
However, before changing the regulations, the government wants to quantify the extra cost to the construction industry and show it is justified. The ODPM needs input from the construction industry on the changes, as they have significant cost implications.
There are two main changes proposed to Approved Document B. As it stands, the changes will make it mandatory that:
? where a multi-storey flat has a height of more than 7.5m between the entry level and the top level, it should be fitted with residential sprinklers and a protected stair; and - residential buildings with a height greater than 30m should be equipped with residential sprinklers.
The first requirement, which relates to the case of an apartment with more than two levels, will apply infrequently.
However, it is not unusual for residential apartment buildings to rise to a height greater than 30m. The ODPM's guidance is that the extra cost of sprinklers would be £900 per apartment, costing the industry a further £200,000 per year nationally. It calculates this from its statistics showing that 222 apartment buildings higher than 30m are completed each year.
The ODPM assesses the social benefit of residential sprinklers as equivalent to saving four lives and preventing seven injuries a decade. It assesses the cost benefit in healthcare terms, etc, to be £500,000 per annum - more than offsetting the cost.
But that's a cost to construction and a benefit to the health service.
A construction output of 222 apartments per year in developments higher than 30m high isn't very many - after all an apartment building higher than 30m will have at least 11 floors and provide at least 50 apartments. If we were building more than four of these a year, then the social cost benefit analysis might be even better. The figure faced by industry would be higher too.
There is, however, some reason to query the £900 per apartment allowance for sprinklers used in the ODPM's forecast.
In a development value sense, the increased storey heights to accommodate sprinklers will often see the number of storeys (and hence apartments) reduce wherever there is a planning height restriction. The loss of space to sprinkler tanks and the like will also reduce net accommodation areas.
While some evidence suggests that fully sprinklered apartment buildings enable fire ratings to be reduced (leading to more open planning of flats, etc), the BRE's recent research does not find conclusive proof of these benefits. In the ODPM's draft proposals, because sprinklers are scheduled to become mandatory, a significant negotiating tool will be removed from fire engineers.
No longer can they 'offer' to include sprinklers for dispensations elsewhere. Under these proposals, that avenue is stopped off.
The second big proposal in the consultation is the proposal to 'discount' - ie ignore - one stairway in all buildings over 30m high wherever phased evacuation is applied. This arises from the events at the World Trade Center, and the difficulty encountered there in evacuating occupants when fire fighters were using the same stairs to access the building.
The proposal will require either an additional stair to be provided throughout the building, or stair widths to be increased to an equivalent dimension to cater for the extra traffic. Hence a current compliant building with four 1,200mm-wide escape stairs will have to be provided with either five 1,200mm stairs or with the width of its four stairs increased to approximately 1,600 mm.
The ODPM estimates this proposal will cost a further £34,000 per storey with an annual loss of rental of £8,000, thereby making an additional annual construction cost of £27-35 million and a rental loss of £6.9-8.9 million. (The estimate does not reckon the aggregated year-on-year loss of rental. ) Again these figures seem low, given they apply to the whole construction output of England and Wales. The ODPM does not measure the benefit in terms of lives saved or costs. It is a 'proactive' change - a response to new awareness.
The smaller the building's footprint, the more impact this proposal will have. For example, a building currently complying with two stairs will face a 50 per cent increase in space taken by stairs - proportionally twice that of the larger floorplate of a four-stair building.
Other issues to look out for include a reduction in hose-length distances to assist fire fighters; decreasing the building height threshold where wet risers will apply; and further clarification about travel distance separation. In residential buildings, it is proposed that self-closers may be omitted from fire doors to habitable rooms in apartments to prevent the tendency to wedge doors open, and further options for smoke ventilation to common corridors.
The ODPM now seeks responses to its proposals to verify its assumptions. Building-control and fire-service departments in England and Wales are expected to favour the proposed changes where these will tighten the specification for the building. However, the construction industry is unlikely to support them on grounds of cost, which could be significant.
Architects should download the consultation document from the ODPM website and respond with relevant information and views on the proposed changes.
Apparently, all responses will be considered, but to have an effective influence the construction industry needs to respond to these proposals in numbers. Submissions are due by 18 November, responses will be published in 2006, with a new standard expected to be released in October 2006, with implementation in April 2007.
Kathryn Lewis is an executive fire engineer with Hoare Lea Fire
SUMMARY OF PROPOSED AMENDMENTS TO PART B (DWELLINGS) BROKEN DOWN BY PURPOSE GROUP
1(a) Apartments (formerly known as fl ats and maisonettes) ODPM is MINDED to remove the provision for any form of self-closing device within an apartment, other than doors opening onto common escape routes Revise guidance on the provision of ventilation systems suitable for the protection of stairways ODPM is MINDED to introduce a provision for sprinkler protection in new high-rise (30m+) apartment buildings subject to further assessment in the light of response to the consultation and more accurate cost data 1(b)and 1(c) Dwelling houses ODPM is MINDED to remove the provision for any form of self closing device within a dwelling house, other than doors to garages Clarify that a suitable system of smoke alarms may be required where an extension is proposed ODPM is MINDED to remove separate loft conversion guidance so that, with respect to the provisions for means of escape, all 'loft conversions' in two-storey houses are treated in the same way as a new three-storey house All dwellings All dwellings Include a provision for an additional smoke alarm in the main bedroom.
Enhance provision so that cavity closure around windows and doors meets a reasonable standard of fire resistance. Introduce provision for cavity barriers in floor voids