Maximum Gap For Fire Door Thresholds

When speaking with manufacturers however a common statement is that a fire doors gap of up to 8 mm underneath the door is permissible.

Maximum gap for fire door thresholds. Current model codes call for some doors to have a maximum air leakage rate of 3 0 cubic feet per minute per square foot 0 015424 m3 s m2 of door opening at 0 10 inch 24 9 pa of water for both the ambient temperature test and the elevated temperature exposure test. Frames used in masonry walls may be used with a maximum 3. In general clearance for those allowed gaps are as follows. Under the bottom of a door.

Nfpa 80 fire doors and other opening protectives. What is the maximum you can have between the bottom of door and the thresholds for a fire rated door assembly i have some stairwell doors with 1 inch to 1 inch gap between the bottom of the door and the threshold. Ings for a basic fire door frame unless the labeling on the frame specifically states that the frame is rated for something less than 3 hours. 3 4 between door and frame.

Clearance between the bottom of the door and the portion of the threshold directly under the door see. It is through extensive testing of fire rated doorsets together with knowledge of the pressure regime within a fire test that a larger gap is permitted at the threshold of the door. If a frame bears a recognized label qualifying it as a fire door frame it may sup port a 3 hour a 1 1 2 hour a 3 4 hour or a 1 3 hour door. There is negative pressure at the threshold during test conditions and so cool air is drawn in underneath the door.

I work in a relatively new office buiding that has internal fire doors with cold smoke seals and the gaps under the doors range from 5mm to 10mm. That will be a problem according to section 8 3 3 1 of the 2012 life safety code you must install fire rated door assemblies in accordance with nfpa 80 2010. 1 8 for more detailed gap information refer to nfpa 80 section 6 3 1 7 and section. Bs9999 2008 recommends for fire doors with cold smoke control that the threshold gap should be either less than 3mm in height or should be fitted with a threshold seal.

1 8 meeting edges for a pair of doors. Contains information on maximum gap allowances for different types of fire doors. In many cases the installation instructions require a maximum of 1 8 in. If a door is to work effectively in its normal role the door leaf must be free to move within the frame and in order to achieve this there must be a gap around the perimeter.