What is the primary characteristic of beam detectors?

Beam detectors primarily utilize a light beam, which, when interrupted by smoke or combustion particles, signals the presence of a fire. This technology relies on the principle that as smoke enters the path of the light beam, it scatters the light, causing a drop in signal intensity that triggers the alarm.

This method is particularly effective for large, open spaces where traditional point detectors may not respond as quickly or accurately due to the volume of area they cover.

The other options represent characteristics associated with different types of detection technologies. For instance, options related to small areas, chemical sensitivity, and sound wave operation describe different categories of detection methods that do not apply to beam detectors. Thus, the focus on how beam detectors operate with a light beam directly connects to their primary characteristic.