THE USE OF LOW-POWER CARBON-MONOXIDE SENSORS TO PROVIDE EARLY WARNING OF FIRE

At present, smoke, heat and light detectors generally used for early warning of fire all have limitations. Carbon monoxide (CO) sensors offer an alternative means of detecting fire and gave good overall results in a trial consisting of six standard fires. However, current CO sensors operate at temperatures of 300-degrees-C or above and have power requirements that make them unsuitable for general applications. Harwell Laboratory was commissioned to determine whether sensors could be fabricated which were sensitive to CO in the range 10-100 ppm and insensitive to other gases. CO-sensitive devices with high surface area were dusted with an optimum distribution of precious metal particles. The addition of the metal reduced the effect of moisture which is usually apparent and a response to CO was even seen at 20-degrees-C. Sensors based on this principle appear to have potential as low power fire detectors.