We have optimised the labyrinth of an optical scattering
smoke detector by optical simulation. We replaced traditionally
used hardware prototypes with a sequence of CADgeometries
improved step by step, the so-called ‘‘virtual
prototypes’’. Further, we have calculated the optical
characteristics of an optical scattering smoke detector, i.e.
the zero-smoke signal, and the response signal to test fires.
We have succeeded in reducing the zero-smoke signal to a
very low level and we could estimate the response signal to
test fires to a sufficient precision of a factor of