I'd say it totally varies.

My smoke alarm at home will go off after a steamy shower.
We smoked hookah in the room and my dorm smoke detector didn't go off. (Extremely stupid idea, looking back though)

Use this trick: tape a bag over the smoke detector

If you make it airtight you could even hotbox that shit. Except your RA would probably be able to smell it from the other side of the building.