While these figures show a remarkably high success rate, the reported causes of failure indicate that the performance of sprinkler systems can be improved if measures are taken to avoid what are considered to be preventable failures. This rate of failure is approximately the same as that reported in the New York study. The Australian-New Zealand statistics, however reveal a higher reliability rate. While some of these failures may be unavoidable, the majority could have been prevented through good design and maintenance practices. Lack of water as a result of closed valves, for example, is preventable with appropriate electrical supervisory equipment for the water supply.
Failures can also occur as a result of incomplete sprinkler protection.
In many buildings, only certain areas may be sprinklered. When a fire originates in or spreads to an unsprinklered area, the fire cannot be suppressed. This type of failure is also preventable with appropriate sprinkler protection. Sprinkler systems are designed to deliver sufficient water flow to the system based on the level of fire hazard for that occupancy. An inadequate supply of water to meet the design conditions can seriously reduce the effectiveness of the system to the point where failure can occur.