Projected beam-type detectors should be kept clear of which type of obstacles?

Projected beam-type detectors are designed to detect smoke by projecting a beam of light from a transmitter to a receiver. For these detectors to function effectively, it is essential that the path of the projected beam remains unobstructed. Opaque obstacles block the light beam entirely, preventing the detector from receiving the signal it needs to determine the presence of smoke. If any opaque objects impede the beam's path, it can lead to false alarms or, more critically, a failure to detect a fire when smoke is present.

Maintaining a clear path ensures that the beam can travel uninterrupted. This is crucial for the reliable operation of the system, as the detector relies on the absence of an unobstructed light signal to assess the air quality for smoke detection. Therefore, keeping projected beam-type detectors clear of opaque obstacles is fundamental to ensure that they can perform their intended function effectively.