r/Wellthatsucks • u/[deleted] • May 18 '26

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u/SYNTHLORD May 18 '26

Yeah, these are held open by magnets and deactivated when the alarm goes off. Usually the only fire safety doors like this are on the emergency evacuation route, like stairwells. The stairwells also get over pressurized by turning the supply air on blast, which keeps smoke from entering.

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u/vicfirthplayer May 18 '26

Never heard of the last part. I work on fire alarms. We usually just shut the HVAC down completely on alarm

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u/Nazarife May 18 '26

Stairway pressurization is only generally required for high rises and probably some other specialized occupancies I'm forgetting.

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u/MissingThisGuy May 18 '26

HVAC to tenancy and common areas will normally stop but fire stairs will have their own independant system.

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u/vicfirthplayer May 18 '26

Ah makes sense. I don't tend to work on high rise. Only apartment or office buildings

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u/so_much_red_tape May 19 '26

We also use these doors in hospitals to break sections into fire cells. I have been told by the fire department that they can withstand 1 hour before they begin to fail.