What is a child-mother fire door? Where is the main application? How to calculate the clear width of the child-mother fire door?
The son-mother-type fire door is a special double-leaf side door, composed of a door leaf with a smaller width (child door) and a door leaf with a larger width (parent door). Normally, the sub-doors are fixed by bolts and no door closers are installed, that is to say, such sub-doors do not have the function of automatic closing.
According to the requirements of the specification: Except for the tube well inspection door and the door of the residence, the fire door should have the function of self-closing. Therefore, except for tube well inspection doors and residential doors, it is not advisable to use mother and child fire doors in other places. If it is really necessary to use a combination fire door on the evacuation passage due to special circumstances, and only the mother door is equipped with a door closer, management should be strengthened to ensure that the child door is locked and closed, and the clear evacuation width should only be included in the mother door. The effective clear width after the door is opened shall not be included in the clear width of the sub-door.
