I work in a backpacker hostel in Australia. Of course smoking is not allowed inside the building and there are smoke detectors in every room and corridor.
By law in Australia the smoke detectors in backpacker hostels set off a fire alarm which we are not permitted to turn off and the fire department is automatically notified. The entire hostel must be evacuated until they arrive and only they are permitted to turn off the alarm. Even in the middle of the night and bad weather. The charge for a false alarm is nearing $1,000.
(These regulations are specific to backpacker accommodation due to a couple of fires in which many travellers died.)
A couple of weeks ago I saw for the first time a guest "vaping" an e-cigarette. It emits a vapour that looks similar to cigarette smoke. He told me that it's fine to use these things indoors.
But I wonder, do smoke detectors specifically and only detect smoke particles? Is there zero possibility that e-cigarette vapour could ever set off a smoke detector?