Fire Safety Science Digital Archive

Measurements have been made, at ceiling level, of the optical density per metre of smoke from slowly developing wood crib fires. Results are given for ceiling heights from 2.4 m to 7.0 m (8 ft to 23 ft) above the fire, and for horizontal distances up to 9.8 m (32 ft) across the ceiling. In these experiments, the change in potential across the open chamber of an ionisation smoke detector, and the output signal from an optical-scattering smoke detector were also continuously recorded. In addition, the response times of some proprietary smoke detectors were measured. The significance of the results in relation to a suitable sensitivity test for smoke detectors is discussed.