Normally closed fire doors are usually closed under the action of door closers, so they can prevent fire and smoke from spreading in case of fire. Normally open fire doors are usually opened under the action of fire door releaser. In case of fire, the fire door releaser automatically releases, and the fire door is closed under the action of door closer and releaser, thus preventing fire and smoke from spreading.

ZHTdoors albaabbada dabka, 31 sano oo waayo-aragnimo wax soo saar ah oo albaabbada dabka iyo Daaqadaha. Albaabada dabka UL ee ugu muhiimsan, albaabada dabka EN, BS EN albaabbada dabka, iwm.