Fire door gaps

[RRR 0]

What is the recommended gap for a notional FD30S timber doorset at the door to floor, there are fire and smoke seal on the leading edge,top and hinge side but nothing at the bottom. The gap at the bottom is 12mm, what is the regulation on this type of door.

[Neil ashdown 0]

BS 8214: 2016 Timber fire door assemblies: Code of practice states that, for doors that must restrict the spread of cold smoke, the threshold gap should be no greater than 3mm at any point. 

A 12mm gap is likely to be too large even for a fire door without the restricted spread of cold smoke requirement.  You will likely need to install a threshold plate to the floor in remediation. 

[James Gormley 0]

Hi,I'm supervising on a 20 story apartment block built 10 years ago.  Reducing the gaps head and sides 3mm + or - 1mm so 4mm max.

There are 450 communal doors to have remedial work done to them,  we are reducing the gaps, changing all hinges, changing the intumisent smoke seals, batt and mastic between frame and structure.  The threshold gaps are very bad, we have been told that the maximum permitted threshold gap is to be 10mm. The average gaps is 15mm with the worst 27mm.

I have been told that the manufacturer s certificate will not allow hardwood edging strips to be glued and screwed to the bottom of the door.  I suggest an 8mm metal threshold strip screwed to the carpets.  Was told this would cause a trip hazard. 

What would be the correct solution