There is a threshold for what level constitutes smoke being detected so generally if you are only producing a small volume away from the unit, it will not be concentrated enough by the time it reaches the detector to set off an alarm. read more
If it's a small enough room most charcoal will set off a carbon monoxide detector when you're lighting them. Not the smoke detector though. read more
Nope smoke detectors don't always detect smoke but heat, certain compounds, and sometimes density of the smoke. Trust me look around they are there in the smoking sections of ever restaurant and hookah lounge. read more