this post was submitted on 21 Aug 2025
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Most people seem to assume fire alarms are false alarms. Is that how it's always worked? What can be done about it? (lemmy.ml)
submitted 3 weeks ago by monovergent@lemmy.ml to c/asklemmy@lemmy.ml
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Most times when I hear an alarm (presumably for fire) go off in the office or a public place, it goes as such:

  1. Observe for any signs of actual emergency: smoke, smell, flame, first responders, or panicking crowds
  2. If nothing unusual seen and nobody is getting up, assume it's a false alarm and continue with task at hand
  3. (Most of the time) Alarm was false and goes away within a few minutes
  4. (<1% of the time) There is indeed a fire somewhere in the building and people take their time gathering belongings before leisurely walking to the nearest door

Same goes in the house:

  1. Wake up groggy, assume false alarm again
  2. Put on pants, check out the source of the noise
  3. (4 times in current residence) Find no indication of fire, hush alarm
  4. Alarm shuts up with a dose of compressed air. If not, sledgehammer time and buy a new one the next day.

That can't be how most of us are supposed to go about it, right?

Is it for a lack of better smoke detection technology? A consequence of buying low-quality detectors? While we're at it, can anyone recommend a smoke detector that does its job with a minimum of false alarms?

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[โ€“] glowing_hans@sopuli.xyz 17 points 3 weeks ago* (last edited 3 weeks ago) (2 children)

Just want to say: False positives for a firealarm ... are much better than a false negative, meaning fire without an alarm.

This makes it really hard to argue for anything other then the status quo without reducing security.

(<1% of the time) There is indeed a fire somewhere in the building and people take their time gathering belongings before leisurely walking to the nearest door

/ positive negative
true true positive, there is a fire ๐Ÿ”ฅ and alarm is on ๐Ÿšจ, peoples lives saved true negative, no fire, no alarm, no worries
false false positive, the situation you want to avoid ๐Ÿšจ, bad false negative, there is a fire ๐Ÿ”ฅ, but no alarm, really bad
[โ€“] Tenderizer78@lemmy.ml 16 points 3 weeks ago (1 children)

Problem is, too many false positives can turn every fire alarm into a true/false negative. If it goes off too many times, people don't act appropriately when there actually is a fire.

[โ€“] lightnsfw@reddthat.com 5 points 3 weeks ago

It happens often enough at my job that I don't even bother to check if it's real anymore. If i hear screaming I guess I'll head for the door.

[โ€“] glowing_hans@sopuli.xyz 6 points 3 weeks ago (2 children)

Essentially this article explains it https://en.wikipedia.org/wiki/Recall_(information_retrieval)

Since the cost of a false negative is really high, people would die in such a case, you want to optimize for recall.

[โ€“] Reverendender@sh.itjust.works 8 points 3 weeks ago

Yeah, but the mild inconvenience though

[โ€“] whyNotSquirrel@sh.itjust.works 2 points 3 weeks ago (1 children)

In most places I worked or studied, if the fire alarm went off, everyone was obliged to go out, false alarm or not

[โ€“] sylver_dragon@lemmy.world 2 points 3 weeks ago

Last place I worked on site was the same. I sat in a SCIF, so there was only a single door, no windows, sound deadening padding on the walls and white noise pumped in. We weren't hearing shit in there. So, if the fire alarm went off, we all grabbed our things and walked out. Not leaving for a fire alarm was grounds for adverse employee actions. We also had a lady from OSHA come through regularly and give management hell for any life safety issue. Complete hard-ass, and we were all safer for it. This is really how it should be. There's too long a history of workplaces putting their employees at risk to eek out the slightest bit more profit.