That's a Siemen's FP-11. It has two sensors that detect the presence of fire.
One is an optical particle sensor that detects dense smoke particles when they obscure a laser inside the unit. It triggers at 2%-4% obscuration/foot.
The second sensor is a thermal filament that breaks at 140F. (specs say 100F, but I know that's a safety buffer)
For the detector to trigger the alarm, you would have to trip both sensors at the same time. As long as you don't get your room too hot, you can vape as much as you want!
sources:
https://www.manualslib.com/manual/152627/Siemens-Fp-11-Fireprint.html#manualAnd 3 years in the fire protection industry
[spoiler:lit]never thought I would get the chance to write about fire safety on 4chan[/spoiler:lit]
