I have been farm setting at 2 farms that have had faulty fire alarms. One went off in the barn apartment. I was able to look in & see there was no smoke. The other farm, they have an alarm system & it evaded up causing a fire dept. run.. We got there at about the same time. Both were faulty alarm units. One said that before a spider had crawled in one & set it off....go figure. It's not just smoke that will set them off.

The noise is definitely irritating