There are three commonly used smoke detectors available, and the likelihood of vapour being detected as smoke by them depends on which kind is being used. These models are:
The least commonly used, and the one that poses fewest problems for vapers, is the Heat Alarm, which is used mostly in kitchens and triggers based on the level of heat it detects and not the amount of smoke. As there are no problems with the heat produced when vapers vape, there should be no problem using a vape pen around this kind of alarm.
Ionisation-based smoke detectors work around a small amount of radioactive material that sits between two electrically-charged plates. This ionises the air within the device and generates a current that smoke particles break, thus triggering the alarm.
As this kind of detector works on a particle level, it can be very sensitive to changes in environment. With vape pens producing vapour and not smoke (and therefore different kinds of particles), they shouldn’t often set off ionisation-based detectors, but they have been known to.
The final kind of smoke detector is the most common and the most likely to be triggered by a vape pen. Photoelectric detectors use optical light beams to detect smoke in their vicinity. If there’s enough smoke surrounding the detector, the light beam is broken and the alarm is triggered.
There’s less risk of this happening with vapour than there is with smoke, but it’s still possible. If there’s enough vapour present to break the beam, the alarm will trigger, regardless of the fact it’s not actually smoke.
There’s no firm rule for using vape pens around smoke detectors. Some detectors may be triggered, some may not. The best thing to do is judge each circumstance on its own merits. If you produce a lot of vapour and you’re in very close vicinity to a smoke detector in a crowded or sensitive area, it’s best to not vape. This way you remove the likelihood of triggering the alarm and causing problems for yourself and those around you.
If, on the other hand, you’re in your own home, the home of a family member or friend, or you’re a significant distance away from a smoke detector, blowing your vapour away from it, there should be no problem. You’re cutting the risk of triggering the detector by keeping vapour away from it, and even if it does go off, you’re in a controllable environment.
As always though, if you’re in an area that strictly prohibits the use of a vape device, follow the rules and do not vape.