If an existing single storey shop is extended so that it exceeds the maximum 2000m2 compartment size, Is it necessary to install a sprinkler system?
Regulation 4 of the Building Regulations 2000 states that “building work” should comply with the applicable requirements contained in Schedule 1. Regulation 4(2)a then goes on to state that, “after the work is completed, the building as a whole should comply with the applicable requirements of Schedule 1 or, where the building did not previously comply with any such requirement, is no more unsatisfactory in relation to that requirement than before the work was carried out.”
Where an existing shop is extended such that the final floor area is greater than 2000m2 (whether it exceeded this value previously or not) then the building as a whole may be less satisfactory in relation to requirement B3(3) than before the work was carried out.
Therefore, the building would have to be either subdivided to limit the compartment size, fitted with sprinklers or some other solution would be necessary in order to satisfy regulation 4(2) in relation to requirement B3.
Regulation 4(2) must be judged against the requirements set out in Schedule 1 rather than the Approved Document. B3(3) requires sub-division of the building “to an extent appropriate” to its size and intended use and it may be that some buildings will still comply with B3(3) by virtue of its intended use even though they have been extended without further capitalisation.
Paragraph 8.14, ask for blocks of flats over 30m to be sprinklered, do all flats need to be sprinklered or just those above 30m?
In blocks which are taller than 30m in height all the individual flats throughout the building should be sprinklered. However it would not be necessary to provide them in the common areas such as stairs, corridors or landings.
Paragraph 8.14 asks for a sprinkler system in accordance with BS 9251 for blocks of flats over 30m, but the scope of BS 9251 states that it should not be used in buildings over 20m in height.
For the purposes of meeting the provisions of Paragraph 8.14 the limit on the scope of BS 9251 to buildings below 20m can be ignored. However, the other limits such as the number of sprinkler heads per room should be observed.
If I provide sprinklers in a block of flats can I reduce other fire protection measures?
This would be a matter for the designer and the relevant building control body to consider. However, any such proposal may result in the need to upgrade the specification of the sprinkler system and the duration of water supplies.
Could increasing the period of fire resistance to walls and floors in a block of flats be a reasonable alternative to providing a sprinkler system in blocks of flats over 30m high in accordance with paragraph 8.14?
Increasing the period of fire resistance of the compartment walls between flats beyond that specified in the Approved Document is unlikely to have any significant impact on the safety of occupants of the building and would have no discernable benefit to persons in the flat where the fire has started.
It is estimated that the provision of a BS 9251 sprinkler system within a dwelling will reduce fire related casualties by around 70%. Whilst it would be desirable to install such systems in all dwellings it was decided that it would only be reasonable to impose this on larger buildings.
This was following analysis of the costs and benefits in the research report: The effectiveness of sprinklers in residential premises and consideration of the increased hazards for fire-fighters and other persons associated with fires in tall buildings, as discussed in the Regulatory Impact Assessment:Changes to Part B (Fire safety) of the Building Regulations 2000 (as amended) and Approved Document B.
The 30m trigger height is considered to be a logical provision which aligns with the provisions for sprinkler protection for other building uses.