To ask the Secretary of State for the Environment what percentage figure of reliability for sprinkler systems he took into account when establishing the parameters for minimum periods of fire resistance in approved document B (fire safety) approved for the purposes of the Building Regulations 1991.

Estimates of the reliability of sprinkler systems vary, and no one figure was used as the basis of the new guidance. However, the opinion of experts at the fire research station, and of the Fire Advisory Panel which the Department consulted while developing the guidance, was that a fire resistance reduction could be allowed over a wider range of cases than hitherto when a sprinkler system was installed.