A laboratory-bench scale method for measuring the sensitivity of smoke
detectors is desirable. To be of value, the laboratory test must be capable
of predicting the response of a smoke detector to real fires. This Note
discusses how far this requirement can be met with a smoke-tunnel (0.63 m^3
volume) of simple construction. Experiments are described which simulated,
in the tunnel, an important phenomenon observed in full-scale fire tests,
namely, the dependence of the response of an ionisation-chamber smoke
detector on the age of the smoke.
Some suggestions for future work directed towards improving the
tunnel are made.