Fire door gap

[Guest Nick Batchelor]

Hi, I've had a builder replace a flat door with an fd30. It strips along the side of the door, but not at the bottom or top I think. Are these required? Also, when it was installed it had a 50mm gap at the bottom. I pointed this out and the builder added some material (assumed hardwood) to bring the gap to 3 mm; is that acceptable? 

 

Thanks for any assistance. 

 

Nick Batchelor 

[Neil Ashdown MAFDI]

Doors to flat entrances should be FD30(s).  This means fire and smoke seals should be fitted at the top edge and both vertical edges, the smoke seal should just about fill the gap between the door leaf and door frame without causing hindrance to the self-closing action.

The gap requirement at the threshold is 3mm maximum, for a fire door that should provide cold smoke protection.

On fitting a hardwood lipping to the door bottom edge to reduce the gap, this depends on whether or not this is permitted by the door manufacturers' installation instructions/product data sheet.  Check with the door manufacturer as to whether or not such work will void any fire performance certification applicable to the door leaf.

Edited June 1, 2019 by Neil Ashdown CertFDI
Additional info

[Nick Batchelor]

Thanks Neil, much appreciated. Will get back onto him.

[Guest Mark]

Does every fire door need fire and smoke seals ? 

[Tom Sutton]

Not necessarily it depends on the type of fire door required if it is an FD30/60 fire door then a cold smoke seal is not required, if they are an FD30/60s type of fire door then they are. All fire doors to modern standards do require intumescent strips fitted to both sides and the top edge.

[Guest Mark]

Thanks Tom but i'm still a little confused.  So what is the difference between FD30/60 fire door and FD30/60s type of fire door if one requires cold smoke seal and one doesn't ? 

[AnthonyB]

The s suffix designates a fire door requiring a cold smoke seal (brush or fin), usually where escape routes need protecting. Both doors will seal in their frame after exposure to high temperature as the intumescent seal expands, but the door without a smoke seal will let cool smoke through for a period until the room reaches sufficient temperature to activate the intumescent.