Optical fiber detection system : OPTIAM - a fiber-optic fire detection system

Designed for factories and plants, this next-generation disaster-prevention system detects unusual changes in temperature, to prevent fires before they can happen.

A laser pulse is sent through the optic-fiber cable from one end. As the pulsed radiation passes through the fiber, it produces backscattering according to the temperature. Temperature information is measured according to the strength of the backscattering, and distance is measured by the time taken for the backscattering signal to arrive. In effect, the optical fiber acts as a sensor, meaning that the structure, and thus maintenance, is simple.

By measuring through sending laser pulses alternately from either end of the optical fiber, detection accuracy is drastically improved, even over large distances. Furthermore, in the unlikely event that the optical fiber is cut, the system automatically continues monitoring, meaning that no areas are left unmonitored.

With previous sensors, alarms are not issued until the temperature at areas surrounding the sensors reaches around 70°C. Also, because sensors are installed in the ceiling, by the time the alarm was activated, the fire has taken hold of the floors and walls in many cases. On the other hand, with OPTIAM, the temperature at which alarms are activated can be pre-programmed to any desired set of temperatures (example: 40°C, 50°C, and 70°C), and can be set to issue alarms at multiple levels. Thus, even the smallest fire is detected by OPTIAM.

Monitor temperature distribution at 1-meter intervals in real time using the color display. Because the location of any abnormalities can be pinpointed very accurately, fires can be detected before they erupt, and in the event of a fire, information needed for fire-fighting can be grasped and relayed effectively. The structure is simple - one optic-fiber cable to be laid.

Optical fibers in an SUS (stainless steel) pipe are operable in temperatures ranging between -50°C and 350°C. Naturally there is no effect from electromagnetic induction, something that can be a problem with electric temperature sensors.

Utility tunnels such as road and rail tunnels carry an increasing number of lifelines such as power and telephone lines. The main disaster-prevention function of these tunnels is to pinpoint the location of major infrastructure abnormalities. Because OPTIAM is able to measure temperature changes at 1-meter intervals, emergency situations can be located easily.

One of the main problems with fire prevention for electric power equipment is that the devices are often unmanned. Also, electromagnetic waves resulting from high voltage can adversely affect sensors. However, OPTIAM performs remote monitoring without interference from electromagnetic waves.

Buildings are becoming taller and bigger, thus increasing the fire risk. However with OPTIAM, centralized monitoring from a control room is possible, thus reducing the manpower spent on disaster prevention. OPTIAM is also ideal for multi-story car parks, which are often unattended at night.