How do fire doors work?
Fire doors have special seals that prevent cold smoke from passing through the small gaps between the door and frame. Fire door seals fit into the groove in the frame and shouldn’t get in the way of the door closing, if it does, the seal will need replacing. There are also seals for the hinges, locks or latches on the door, these are called interdens and each manufacturers test evidence will let you know if these are required. The other defence fire doors offer is a door closer, which lets users open the door but then pulls the door back after the resistance from the person leaves the door. Ensuring the door stays closed makes sure that the seals and doors work together and are preventing the spread of fire from room to room.
Fire doors can be locked shut as indicated on the fire door signage attached to the door leaf face, although they are only usually locked if the property they are installed in is empty or the door is on an electrical or service riser cupboard. An exception to this is hotel fire doors, which need to be locked for guests’ privacy. These doors are full of components that have been tested and put together to provide a fire door in a specific wall (known as a Fire Compartment Wall) to block not only the fire but the harmful cold smoke as well.
Fire escape doors usually open outwards. This is so when people are escaping, they can run straight out of the door, rather than having to pull the door back. In places like hotels and blocks of flats, fire doors can save lives and buildings. They will hold back the fire for as long as they have been designed to, as long as they have been fitted and maintained properly. Therefore, while the door is doing its job, the firemen are arriving at the property, starting to put the fire out, which wouldn’t have spread much due to the door. Also, the other residents in the building are able to escape out of harm’s way.
Fire doors have to use three hinges mainly because of how heavy the door is, compared to a normal average door which has two, but each door manufacturer will let you know how many hinges are required and at what positions on the door edge. Also, if the door has already been tested, the hinges and everything else that has already been placed on the door have to stay in the same position and place. The door is otherwise known as ‘unsafe’ and non-compliant.
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