Smoke detectors etc

[dynamicduo]

On a recent hotel stay we were all evacuated in the early hours of the morning as the fire alarms went off. Afterwards a member of staff said it was probably someone smoking in a non-smoking room. Are the detectors less sensitive in smoking rooms (the very rooms where a fire is perhaps most likely to start)? What is the difference in alarm systems between the two types of room.

[Loosehead]

I would imagine that there are no detectors in the smoking rooms.

[curlyfilm]

some smoke detectors are not smoke detectors as such, they go off when when they sense a rapid rise in temperature

[theprof]

A few years back, I did a stint as a visiting professor at Harvard.

Various communal rooms on the uni campus had detectors which were sensitive to UV light. I think their correct name is UV optical flame detectors.

These detectors would pick up someone merely striking a match in the room, resulting in the activation of the central alarm network. Furthermore, they were so sensitive that they would detect the glowing end of a cigarette even if the cigarette had been lit outside the room. Believe me, they were a right pain in the neck especially since I don't smoke myself.

The ionisation chamber and optical types we use in UK are far better in my view.

[Gef]

I think the member of staff was talking nonsense. I smoke cigars and every hotel room that I have stayed in has had a smoke detector and none has ever gone off. I have smoke detectors at home and they don't go off either (yes, I have tested them and they work).

I have also smoked in a non-smoking hotel room (don't ask but it was with the blessing of the hotel staff) and the alarm did not go off.

Either they are all the same or, and this is worrying, none of them work.

[Roden]

I thought a smoke detector worked on the basis of emiting alpha radiation, the radiation can only travel a small distance in air and when smoke psses through the detector it blocks the signal, not sure i was told that in GCSE is that truew?