A study jointly commissioned by the National Fire Sprinkler Network and the National Fire Chiefs Council has analysed over 2,000 fires in sprinklered buildings, using incident reports from all the Fire & Rescue Services in the UK. The researchers found that sprinklers when sprinklers operated they controlled or extinguished 99% of fires. They also found that the operational reliability of sprinklers was at least 94%.
The researchers also found that only one or two sprinklers operated in 85% of fires and that in dwelling fires the average area of fire damage was reduced from 18-21m2 to under 4m2.
The full report is available here.