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.
Fire door frame with threshold.
Simpson offers thousands of choices for fire rated doors including 20 minute fire rated wood doors and mdf doors with fire ratings up to 90 minute.
Top quality solid unassembled frame with threshold sill rebated for 44mm thick door leaf and supplied with aquamac 21 joinery seal.
And since simpson fire doors have been designed to match other interior doors your fire rated doors will blend seamlessly with all doors in your home.
Special consideration should be given to threshold designs used in means of egress or in handicap accessible situations.
Thresholds should be provided under the door and between the frame to allow for a smooth transition between floor coverings of different heights or materials.
The practice of knocking up a door frame on site or in a workshop hanging a door and believing that the result constituted a valid fire door installation was never correct.
Thresholds are rarely mandated by the codes and standards for fire doors or smoke doors but when they are used in these applications thresholds must be listed to ul 10c or nfpa 252.
When speaking with manufacturers however a common statement is that a fire doors gap of up to 8 mm underneath the door is permissible.
Suitable for inward or outward opening doors this frame provides an excellent colour match across the components compared to cheaper options.