Open path smoke detectors
Open path detectors (gas, oil mist, smoke) require a clear and open path.
Open path smoke detectors shall not be installed in open areas where rain, steam or fogmaybe present. Open path smoke detectors shall be mounted in locations where people are unlikely to obscure the beam. The optical path length (the distance between the transceiver and the reflector) shall be restricted to 30 metre, unless analysis of detection systems has been carried out and demonstrate operation at longer path lengths.
Open path smoke detectors may be used in any of the following applications:
• Large open areas where point detectors would be difficult or provide inefficient coverage.
• Air intakes that require incoming air to be monitored for the protection of personnel within the protected area.
• Areas where the expected fire is likely to produce low heat output.
Open path systems shall have a transmitter and a receiver. Systems with a reflector may
be used at approval of the Principal.