The test scenario for the non-fire case is similar designed to functional testing according to EN54. The standard prescribes a light extinction measurement in the near-IR range for the test of smoke detectors based on the light scattering principle. The evaluated measurement parameter is the amount of light loss (due to extinction) normalized by the measurement path, i.e. the extinction module expressed in dB/m and the light obscuration in %/m. However, the extinction
path in the new duct is about 2.5 times shorter than the path in the EN54 duct. Due to the small cross-section and the need for very precise extinction measurement, the extinction measuring device Lorenz AML [14] had to be adapted. The AML is an approved reference measurement system for EN54 tests and consists of a transmitter / receiver module and a reflector. The channel only requires two opposite-facing windows with a diameter of at least 70 mm.