@123kingarthur
Depending where the smoke detector is sited,
Steam from a kettle or shower or as has been said a toaster can set them off.
As can other sources.
You can get some battery ones with a silence button. When they go off as a false alarm you press the button which will reset later when the alarm source will have cleared the chamber.
Never known steam to do it - must be faulty if that happens or badly designed?
Did bit of temp work at fire detector place, they ordered in boxes of tiny spiders to test them out and were also checked for reactions to dust, maybe if clagged up the vents?
Nuisance how they best mounted high up, with ours we have to fix up the stepladder at top of very steep stairs. If I was on own trying to deal with it beeping would possibly just smash it to pieces with broom?
Mate said next doors one was going off beep and they were away for a fortnite, she had real trouble sleeping, very penetrating noise eh?