I'm a bit late to the party, but it sounds like you have a optical smoke detector, it uses a light beam and sets off an alarm when something (ideally smoke from a fire) breaks the beam of light. Unfortunately steam from cooking or fog from a shower or vaping can just as easily disrupt the beam of light. This style has been around a long time and is quicker at detecting fires due to it's higher sensitivity.
Ionization smoke detectors are more accurate at detecting just smoke but not as fast as optical detectors. They have 2 chambers where ions are released into the air, one closed and one open to the environment. Ions attach to the smoke particles in the open chamber and causes an alarm to sound due to the difference in the ions in the chambers. I've had a friend over and we had the room dense with fog, but the smoke detector right outside the door didn't go off, even stood near it vaping many times with no alarm. But accidentally burn something on the kitchen stove down the hallway and the detector goes off despite there not being any visible smoke. Can get pretty cheap disposable 10 year detectors at wal-mart. Mount them, then 10 years later replace them when the internal battery starts to die.