Threshold Drop down seal

[TONY74]

Hi all,

We have just ad a motorised opening FD30S fire door.

It has a threshold drop down seal fitted. However, the gap at one corner is approximately 4mm and the corner it reaches 10mm+

Should the drop down seal just brush along the carpet? 

 

Thank you all

[Neil ashdown]

Assuming the door is timber-based.

In the door-closed position the flexible seal should be 'just contacting and giving an even contact with the floor'   or   'with a leakage rate not exceeding 3 cubic metres per hour per metre at 25Pa  when tested to BS476 part 31.1 or BSEN 1634-3'.  this is taken from BS 8214: 2016 Timber-based fire door assemblies - Code of practice.

At between 4mm and 10mm the gap is unlikely to sufficiently restrict the spread of smoke at ambient temperature.  Generally, the gap between the bottom edge of the door and the floor should not exceed 10mm for fire resistance performance.  Check with the particular door manufacturer for the specific tolerances.

[TONY74]

On 16/11/2022 at 18:26, Neil ashdown said:

Assuming the door is timber-based.

In the door-closed position the flexible seal should be 'just contacting and giving an even contact with the floor'   or   'with a leakage rate not exceeding 3 cubic metres per hour per metre at 25Pa  when tested to BS476 part 31.1 or BSEN 1634-3'.  this is taken from BS 8214: 2016 Timber-based fire door assemblies - Code of practice.

At between 4mm and 10mm the gap is unlikely to sufficiently restrict the spread of smoke at ambient temperature.  Generally, the gap between the bottom edge of the door and the floor should not exceed 10mm for fire resistance performance.  Check with the particular door manufacturer for the specific tolerances.

Hi Neil,

Thank you for your reply. I have measured the gap from the floor to the bottom of the leaf it is 24mm. It does have a drop down seal. When the door is closed i feel its dropped down to the maximum 

I have a copy of BS8212:2016 and for the love of money cant see this in it

[Neil ashdown]

Its BS 8214: 2016 section 12.3

24mm will very likely be too much for fire resistance performance, check the door leaf manufacturers data sheet.