早期探测火灾并及时报警对人身安全起主要作用，早期抑制或消灭火灾将极大地减少财产损失，避免因火势扩大而造成更大的人身伤亡和财产损失。火灾中保障人身安全的一个主要数据是给出一个安全的逃生时间。采用模拟量探测报警系统预测火灾的逃生时间将有可能。采用感烟探测器的火灾自动报警系统及自动喷水或其它固定灭火系统各自起到预防和抑制早期火灾的作用，他们的功能不能相互代替 Early detection of fire and timely alarm plays a major role in personal safety. Early suppression or elimination of fire will greatly reduce the loss of property and avoid greater personal injury and property loss caused by the fire. One of the main data on personal safety in a fire is to give a safe escape time. The use of analog sounding alarm system to predict fire escape time will be possible. Automatic fire alarm system with smoke detectors and automatic water spray or other fixed fire extinguishing systems each play a role in preventing and suppressing early fire, and their functions can not substitute for each other