Using optical fiber grating as the measurement unit and communication optical fiber for signal transmission. Site equipment are characterized by essential-safety explosion protection, intense electromagnetic interference resistance, corrosion resistance, high-precision system as well as stability and duration.

The system may timely display temperature in each section of the tunnel and enable compound alarming for differential and fixed temperature, which may be set manually.

Patent technology is adopted, enabling distributed measurement with hundreds of probes.

Capable of self-checking, providing a highly reliable system.

Site measurement unit has simple structure, and no electrical equipment are in tunnels, thus making maintenance unnecessary.

The system may be connected with computers and fire-fighting control systems, thus enabling automatic centralized control.