Reliability of Automatic Water Sprinkler (AWS) systems

DBI – Danish Institute of Fire and Security Technology – has carried out a statistical analysis of inspected Automatic Water Sprinkler (AWS) systems.

The analysis showed that 97.7 % of the inspected installations in 2008 were approved, a high reliability. This is however a reduction in relation to 2001, where 98.2 % of the inspected installations were approved (note that the 2001 analysis was for a lower number of installations, so the difference can be statistical uncertainty). Of the installations inspected, 37.6 % had no defects in 2008 compared with 47.1% i 2001.

The analysis showed that the three most frequent defects were:

• Incorrect adjustment to building alterations (9.6 % had this fault)
• Incorrect function of fire doors (5.8 % had this fault)
• Not updated logbook (5.5 % had this fault).

• Sprinkler installation not correctly adjusted to building alterations
• Stacking height exceeded
• Distance between storage and sprinkler head too small.