This paper presents the testing results of three types of fire detectors: electrical heat sensing cable, optical fiber Raman temperature sensing detector, and optical fiber Bragg grating (FBG) temperature sensing detector, in two simulated fire scenes in a cable tunnel. In the small-scale fire with limited thermal radiation and no flame, the fire alarm only comes from the heat sensors which directly contact with the heat source. In the large-scale fire with about 5 ℃/min temperature rising speed within a 3-m span, the fire alarm response time of the fiber Raman sensor and FBG sensors was about 30 seconds. The test results can be further used for formulating regulation for early fire detection in cable tunnels.

研究了线型感温火灾探测器应用于电缆隧道场所电缆火灾早期探测的工程适用性。以电缆隧道为应用环境, 基于现有的线型感温火灾元件: 感温电缆、光纤拉曼感温探测器和光纤光栅感温探测器, 建立了实验平台, 设定了不同火灾的实验场景, 记录了火灾模拟试验中的温度变化和探测器响应时间。实验显示, 对于初起无明火的小规模火灾, 其热辐射量小, 除了与其直接接触的感温火灾探测器能做出报警响应外, 其余非接触式的探测器均无法响应。对大规模火灾, 光纤拉曼感温探测器和光纤光栅感温探测器的报警反应时间均在30 s左右, 热电偶记录的火灾发生上方60 s以内的温度都在35 ℃以下, 而±3 m内的温升都超过5 ℃/min。根据3种探测器的技术特点, 分析了典型线型感温火灾探测器应用于电缆隧道场所火灾早期探测的工程适用性, 为规范编写《火灾报警设计规范》的相关条款提供了技术支持。