Availability analysis for a fixed wet sprinkler system

Fixed water sprinkler systems are the most frequently used installations for combating fires in protected areas of buildings. Their successful deployment depends on their being available in case of fire. Therefore a fault tree analysis is performed for a typical design in order to present an approach for establishing a numerical value of its unavailability and to uncover potential weaknesses in the design or maintenance regimes. Several measures are identified that would reduce the unavailability of the system by a factor of 10, without requiring modifications to the hardware. At the same time, they diminish the effort required for maintaining the system prepared for operation. Additionally, the probability of an unrequired opening of a sprinkler head (false alarm) is assessed. The analysis provides an approach for a quantitative support in making decisions on the adequate protection of vulnerable objects by a sprinkler system.