On a linear fire detection using coaxial cables

Abstract

Alarm systems represent a combination of the various modern engineering solutions (electrical, mechanical, hydraulic, etc.) with the primary goal to protect human lives, living and working environment and material properties. Detectors are basic and common components of these systems. There are many different kinds of detectors which usage depends on system solutions, prices and other technical properties of system application. Different types of non-typical lines can be used as detectors in alarm systems, such as coaxial cables or special constructed electrical lines. The change of some parameters of cables, such as capacity, impedance, resistance or similar, according to temperature, pressure, torsion or other disturbances, can be used for detection of intruder or fire. This work presents experimental results obtained on three different types of coaxial cables: RF 75-3-1, RF 75-4-5 and RF 75-7-9 in order to show changes of capacity as a consequence of heating due to growth of surrounding temperature, and consequently, possible application of cables as fire detector. Before an experiment, a simulation of fire in laboratory 113 in Electrotechnical school Nikola Tesla in Nis was made in FDS (Fire dynamic simulator) software to show the possible spreading of fire, and consequently, to find optimal location for coaxial cables as fire detectors.