space between fire door frame and opening

[Neil ashdown]

40mm / 50mm gaps are too large to be filled.   Assuming the door assembly is timber, refer to section 9 of BS 8214: 2016.

I would reduce the gap to 20mm max using tightly fitted solid timber lining screw fixed to the back of the door frame. The lining must be continuous, full width and of similar material to the existing door frame. Alternatively, you could install a new door frame. 

[Guest Russ]

On 16/11/2018 at 07:01, Neil Ashdown CertFDI said:

Hi Michael,

Because gap sizes can vary so much you may have to use more than one fire stopping method.  First of all, I should say that this subject is dealt with in detail by 'BS 8214:2016 Timber based fire door assemblies Code of practice'.

Generally, for gaps up to 15mm you should completely fill the gap to the full depth of the door frame with tightly packed mineral wool. Make allowance though for a 10mm deep capping of intumescent acryilic sealant on both sides. The sealant should cap the mineral wool for a 10mm depth between the frame and the wall and not just to cover the surface of the gap. Intumescents are gap fillers and need surfaces to expand against under pressure, if applied to just a flat open surface they will just foam and fall away so they need to be inside the gap. 

This should be done all around the door frame to wall gap on both sides.

Where the gap is up to 20mm, follow the same method as above but use tightly fitted 15mm timber or MDF architraves to overlap both frame and wall by at least 15mm. For small gaps such as 3mm to 6mm where use of mineral wool is impractical you should fill the gap as deep as is practically possible with intumescent acrylic sealant. 

For especially large gaps line the opening with continuous solid timber and fill any remaining gaps as above.

Blue 60 is a new-ish product specially for timber fire door frames but minimum and maximum gaps apply to its use and the dedicated packers supplied with the foam must be used.  So use in accordance with the product data sheet.

Hope this helps. 

Hi there,

I would like to ask if it is possible to keep the old door frame (760mm) in place to minimise damage and fit a smaller fire  door/frame (680 + 50). As it is not different to the continuous solid timber that you refer in the answer

Thanks

Russ

[Guest CB Fire]

I have been advised that timber can not be fixed to the door frame of timber FD30 door sets to reduce the gap and any reductions must be made by fixing timbers to the substrate. Is this correct?

[Neil ashdown]

Where the gap between the door frame and the surrounding wall is too large to suit the new door-set or door assembly it is, within reason, acceptable to use a timber subframe.  

Clearly, it will be necessary for the subframe and door-set / door assembly to be an intimate fit with each other once installed.   Given this, it would be interesting to understand why the timber subframe should not be fixed to the door frame - only to the wall!  Maybe, in this particular case, the subframe is quite thick?

The structural openings for replacement fire doors should be measured carefully and the door-set / assembly made to suit, so as to avoid adding timber subframes where possible.

[Ruslan Zhivkov]

Hi Neil,

Referring back to the timber subframe in case of an excessive gap. Is it possible to utilize the old door frame to be that "timber subframe" and fit a smaller FD30 with its frame around it to minimise damage to adjacent walls if the fixing embedment depth is achieved.

Regards

Russ

[Neil ashdown]

Possibly.  Assess the existing door frame and its installation to the surrounding structure in terms of compliance with BS 8214: 2016 and the fire door leaf manufacturers requirements.

[Guest Carlos Mckoy]

Good afternoon gents I am currently firestopping on a site, and I have been asked to provide a linear seal to a timber frame FD 30 (where frame meets substrate) which is being installed to a 60min fire resistant block wall, would you be so kind as to assist me with this? If the door is not the same fire resistance as the wall its being installed to can it offer the same fire resistance as the wall?

 

[Neil Ashdown MAFDI]

The fire door will have a fire rating based on a fire resistance performance test on one of its type.  Therefore the fire-stopping to the linear gap between the back of the timber door frame and the surrounding wall cannot provide sixty minutes fire resistance for a FD30 fire door assembly. 

Where the fire door is considered sufficient, seal the linear gap in accordance with the door manufacturers installation instructions or where this is unavailable refer to the Standard BS 8214: 2016 Timber-based fire door assemblies - Code of practice.

[Mike North]

A fire door is normally rated at half the value of the wall that it is installed in,  a 30 min door in a 60 min wall.  Refer to table B1 in Approved Document B Vol 2 2019 Amendment 2020  

[William Austin]

Good afternoon, 

Should an Intumastic water based acrylic sealant being used to seal the gaps between fire door frame and wall have supporting test evidence to validate its use between a timber stud wall and FD30 fire door frame, or would testing to any linear gap such as floor to wall etc be valid?

BS 8214:2016 Clause 9.4.2 Note 4 advises that it should be tested to the application it’s being used in, and I assume this would also mean gap width and depth would also be tested for its performance.

Could any fire rated mastic be used or is it a requirement for it to have been tested for use with a fire door frame and supporting structure?

[Neil Ashdown MAFDI]

Referencing BS 8214: 2016 section 9.4.2  in respect of your questions:

Q1) Should an Intumastic water based acrylic sealant being used to seal the gaps between fire door frame and wall have supporting test evidence to validate its use between a timber stud wall and FD30 fire door frame, or would testing to any linear gap such as floor to wall etc be valid?  A1) It should have test evidence as referenced in 9.4.2 including note 4 and used as illustrated in Tables 2 to 5.

Q2) BS 8214:2016 Clause 9.4.2 Note 4 advises that it should be tested to the application it’s being used in, and I assume this would also mean gap width and depth would also be tested for its performance. A2) The key point is that it should be used as illustrated in Tables 2 to 5. Therefore the test evidence should be checked for suitability.

Q3) Could any fire rated mastic be used or is it a requirement for it to have been tested for use with a fire door frame and supporting structure? A3) The mastic should be as described in 9.4.2 including Note 1 and Note 4.

[54321M]

Good evening,

When fitting new FD30 front entrance doors the internal reveals are considerably finished over the door leg meaning we would fix a sub frame to the substrate, then wedge and firestop off this.  I always thought for an FD30 a soft wood continuous timber was suitable but I have been told it must be the same denisty or greater than the frame even though it is behind the plastered reveal / brickwork and then covered over with a firestopping method. Can anyone advise if this is correct and hardwood must be used??

Also on the external face we have a 10mm gap of intumescent sealant which according to BS 8214:2016 would not require architraves but building control have said we must trim up end of story.

Can anyone recommend a product for external use which would be suitable in a white finish??

 

Thanks

 

[Neil Ashdown MAFDI]

Use of a continuous (length and width) timber subframe is acceptable so long as it meets the requirements of BS 8214: 2016 so the subframe, doorframe, linear gap and the sealing of that gap should be as shown in section 9.4.2.

The material of the subframe should be the same as the door frame, eg: softwood for FD30 and hardwood for FD60.

[Sean Bissett]

Hello everyone, 

 

I`m a Fire Door Inspector and recently came across an interesting door. The Threshold gap was 12mm maybe 13mm and the non knuckle side of the hinge had gap sizes from 8mm to 10mm where the door latch was. 

My question is could you repair this without a new door set and not knowing who the manufacturer is? 

[Neil Ashdown MAFDI]

A gap of 8mm to 10mm between the edge of the door leaf and the latch keep is excessive.  Maybe the latch keep has been overly recessed into the door frame, you don't say and haven't provided a photograph?  If so it should be possible to remove the latch keep and repair that section of the door frame so that the keep can be reinstalled with a tighter gap.

[54321M]

On 21/09/2023 at 08:14, Neil Ashdown MAFDI said:

Use of a continuous (length and width) timber subframe is acceptable so long as it meets the requirements of BS 8214: 2016 so the subframe, doorframe, linear gap and the sealing of that gap should be as shown in section 9.4.2.

The material of the subframe should be the same as the door frame, eg: softwood for FD30 and hardwood for FD60.

Hi Neil,

Thank you for the reply. Regarding the FD30 FED's is there any reason a hard wood ply board could not be pre cut into strips and fixed to the brick sub strate, then we pack the frame off this and firestop accordingly? I understand the material should be the same as the  sub-frame but our client is making us use hardwood only which cost wise will spiral and I do not believe it is required. 

The denisty of the hard wood ply  is higher than the frame density and is re sessed in between a plaster finish and external brickwork, so wondered if this could be an option.

 

[Neil Ashdown MAFDI]

The issue with using plywood for lining the structural opening or adding to the back of the door frame could be one of supporting evidence.  What you say (above) may well be reasonable but you may need supporting evidence from the door manufacturer to satisfy your client.  Best to stick with the British Standard and door manufacturers installation data sheet because that evidence is clearly demonstrable. 

[Guest Sam]

Lots of commentary on situations with large gaps but what about when you have fitted plasterboard to a stud wall (or a block wall that is dot and dabbed) and fitted tight to the door linings which are installed first with gaps no more than 2mm followed by a 3mm skim coat right up to the door lining.  Can you now just fit architraves? Because I have done this for 20 years without any dramas. Yet I am now finding all this talk about filling gaps and having a minimum/maximum gap and using proprietary products like foam and intumescent mastic being required on a new build.  I get it on refurb but what is wrong with doing it properly with plasterboard (12.5mm standard board and a skim) tight to the lining. 

I am on a job now where we are being told to cut it back 10mm and then seal it up with mineral wool and intumescent mastic.  Such a waste of resources, time, labour, materials and money not to mention trashing the environment with the horrific number of tubes of mastic.  It is infuriating all for what on the regs is a 20minute fire door which everyone wants to call 30minutes. Madness.

Lots of details out there on what to do with gaps but no one seems to want to say anything about it having no gap.  Plasterboard has a recognised fire resistance and I have seen it perform in other fire tests remarkably well.  Why would you chop it out! 

Please can someone give me some pointers on how to prove that no gap is compliant.

Thanks Sam

[AnthonyB]

Manufacturer's instructions, based on their certification test data, take precedence. In the example linked below, it allows a gap up to 10mm between frame & wall, states what the gap must be filled with - but does NOT say there MUST be a gap, only giving guidance should there be one. Therefore it is reasonable to assume no gap is permissible (check the install sheet for the particular door you are fitting though or better ring their support line)

https://mbp.co.uk/wp-content/uploads/2019/02/PREMDOR-CF195-installation-guide.pdf

[Neil Ashdown MAFDI]

Remove the door assembly and line the opening completely with solid timber of the same type as the door frame. Then fit the door assembly into the new subframe. Refer to BS 8214: 2016 for linear gap requirements in terms of dimensions and sealing.