Would you recommend the use of heat sensitive cable sensing systems – we have a client wanting to defend cable infrastructure over big distances on an industrial site where some automation comms supporting vital equipment and fire protection signalling cables are located in cable trays installed above ground.

A: The traditional heat sensing cable was a line device with an integrated sensing element built around a pair of conductors kept apart by an insulator with a low and predictable melting point. In the event of fire. the insulation melts, the conductors touch and an alarm signal is sent. There are also solutions which incorporate a material that will only begin to conduct past a certain temperature threshold – any signal on the path is an alarm.

For your application we’d be thinking about something like the NKT Photonics Lios De-Tect, which is a linear heat detection system based on fibre optics. It offers neat things like 10,000 range with interval sampling of 25cm, with a 4-channel configuration having a range of 6000 metres. Most importantly, each channel can be divided into 1000 programmable zones, each with an individual pre-alarm and alarm threshold, giving the system excellent capacity to deliver situational awareness.

Importantly, the flexible and passive sensor element of this system is immune to electromagnetic interference and aggressive atmospheric conditions, is maintenance-free and available as multi-mode or single-mode. De.Tect can be integrated with fire suppression systems based on water mist that dissipate the heat energy from the fire and its accuracy is such it can address an outbreak with extreme accuracy.