Are specific fire door gaps a legal requirement?

[Guest NeilC]

Hi

For fire doors, the building regulations state an equal gap of a minimum 2mm gap and a maximum 4mm gap between the fire door leaf and frame.

Is this just a guideline or is this the law and needs to be strictly adhered to, and if the fire doors' gaps are less then this minimum amount or more than this maximum amount are they considered illegal in the eyes of the law and will need correcting?

When I've used a fire door gap tester I found that all the fire doors I checked were below and above these minimum and maximum gap tolerances.

I've been given conflicting information on this.

Some say this is the law and is strictly needed to be adhered to and others say that composite fire doors don't have to adhere to this regulation and this regulation is only for timber doors.

Please can you confirm if this regulation includes composite fire doors or not and if this is a legal requirement or not?

Thank you for your time and understanding.

Neil

 

[Neil Ashdown MAFDI]

The correct door edge to door frame gap depends on the fire performance test evidence for that particular fire door. So the gap could be more than 4mm for some fire doors and still be compliant with the fire performance test. However for most timber-based fire doors the gap should be between 2mm and 4mm.

If gaps are too large it may affect the door's fire performance and importantly would allow cold smoke to spread past the brush/blade edge seal and thus compromise safe escape. Therefore action should be taken to correct gap issues and cold smoke restriction issues as obligated by Article 17 of the Regulatory Reform (Fire Safety) Order 2005 for England & Wales.

Many people are killed by the effects of smoke spread rather than the fire itself.

Edited June 2, 2018 by Neil Ashdown CertFDI
To correct a typing error

[Guest Dennis Bloomfield]

I have recently surveyed a block of flats and there are a number if doors which are operating correctly but have a minimal gap on both sides. There is no room in the case for adjustments. The smoke seals are very soft fins but in spite of the small gap are not damaged. In doc b it says a gap to ensure the door works correctly with no min mentioned. I did say to the client that the small gap may eventually damage the seal but as they are in tact I can see no real reason for not accepting them. 

Would you agree with this.

 

 

[Neil ashdown]

Agreed. So long as the door leaf self-closes completely to the door stop and sits inside the door frame reveal, and the smoke seals are effective, then from a fire and smoke spread point of view the small gaps would be acceptable. 

[Guest TonyG]

Hi.  I am currently challenging integrity of the fire door installation in my apartment building (new build).  Fire doors (timber) in corridors and leading to stairwells are FD30 rated, and the door frames incorporate intumescent strips and integral brush-type smoke seals.  I have noted that the smoke seals on the intumescent strips fitted the door frame on the opening side of several of the doors have a visible gap between the edge of the brush seal.  The gap between the door edge and the frame on a sample of doors I have measured varies between 5.5mm and 9mm, whereas on the hinge edge the gap is minimal - guidelines appear to indicate 3mm +/-1mm.  The response to my challenge from building management thus far is that all doors and seals meet the required standards.  My impression is that the installations are be door assemblies, not door sets, and while individual components (doors, frames, glass side panels etc.) may individually comply with standards or legislative requirements the assembly as installed does not meet regulations as the installation will not effectively seal against cold smoke and the gap may also exceed what is acceptable for correct operation of the intumescent seals.  I am not an expert in fire doors of this type, but having spent 40 years as an engineer in the oil and gas industry, and with a healthy respect for fire having developed fire-resistant materials for hazardous industries such as oil & gas, foundry and mining industries I do have a feeling for when something looks wrong.  I would greatly value comments from someone specialising in this area.

[Neil ashdown]

If the door leaf to door frame gaps are not as those stated in the fire door's product data sheet/installation instructions, then the the installation is non-compliant. 

If the smoke seal does not fill the gap (though it shouldn't be so tight as to hinder self-closing) then it will not effectively restrict spread of ambient temperature smoke. So the installation is non-compliant. 

The installer should work to the relevant product installation data sheets and to the relevant British and European Standards.

The relevant standards / documents are:   Product installation data sheet for the door leaf and the seals, BS 8214:2016 Timber-based fire doors Code of practice,  BS 476 part 31.1, and BS EN 1634-3.  

More information at the website of the Intumescent Fire Seals Association:    https://www.ifsa.org.uk/ 

[TonyG]

Thanks for that Neil, much appreciated.  I will request product installation data sheets from the building managers to clarify the required gap, although I would expect that for a frame fitted with an integrated intumescent strip and brush-type smoke seal anything greater than a 4mm leaf-to-frame gap would in any event render the smoke seal ineffective.

The entrance doors to individual apartments in the building have intumescent strips but the smoke seals are separate and of a plastic blade type.  Although the apartments are new I identified that my apartment door smoke seal was damaged, and that of a neighbour was not present; I looked at other apartments and found that several more were also defective.  I got an initial response back that as the corridor fire doors had effective smoke seals (see my earlier post!) then that would prevent smoke from entering apartments (despite there being several apartment entrances between sets of fire doors.  Eventually someone saw sense and new smoke seals were installed on the affected apartment doors.

 

[AnthonyB]

They will try and palm you off by saying it got a Building Regulations Completion Certificate - which in actuality means nothing (as Grenfell proved) - if you get no joy get fire service enforcement in to look at it. 

[TonyG]

I have a follow-up question.  As I mentioned the smoke seals on our individual apartment entrance doors have been rectified; this was on the side and top edges.  The bottom edge of the doors incorporates a rebated drop-down door seal as the door-edge to cill gap is about 10mm.  However when the door is closed the seal when dropped still leaves a gap of about 2.5mm.  I appreciate this is less than the 3mm limit for a door-edge to cill gap where no smoke seal would be required, but I would have thought that where a smoke seal is fitted it ought to bridge the gap completely, especially as with the drop-down type there's no risk of interfering with door self-closure.

 

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Thanks for that Neil, much appreciated.  I will request product installation data sheets from the building managers to clarify the required gap, although I would expect that for a frame fitted with an integrated intumescent strip and brush-type smoke seal anything greater than a 4mm leaf-to-frame gap would in any event render the smoke seal ineffective.

The entrance doors to individual apartments in the building have intumescent strips but the smoke seals are separate and of a plastic blade type.  Although the apartments are new I identified that my apartment door smoke seal was damaged, and that of a neighbour was not present; I looked at other apartments and found that several more were also defective.  I got an initial response back that as the corridor fire doors had effective smoke seals (see my earlier post!) then that would prevent smoke from entering apartments (despite there being several apartment entrances between sets of fire doors.  Eventually someone saw sense and new smoke seals were installed on the affected apartment doors.

 

[Tom Sutton]

The purpose of the cold smoke seals on the flat front door is to prevent a fire in a flat smoke logging the common areas. Smoke seals on corridor doors are to prevent a protected area smoke logging another protected area. But it looks like they realised their mistake by rectifying the front doors. 

[Neil ashdown]

"The bottom edge of the doors incorporates a rebated drop-down door seal as the door-edge to cill gap is about 10mm.  However when the door is closed the seal when dropped still leaves a gap of about 2.5mm.  I appreciate this is less than the 3mm limit for a door-edge to cill gap where no smoke seal would be required, but I would have thought that where a smoke seal is fitted it ought to bridge the gap completely, especially as with the drop-down type there's no risk of interfering with door self-closure".

The seal would've been subject to a performance test fitted to a door, so it's best to contact the manufacturer with this question.  I would suggest starting with Lorient at https://www.lorientuk.com/contact

[Guest Zak H]

Hi All, 

I am questioning the 3mm maximum gap on  fire doors.This has been raised on a recent health, safety and fire risk assessment i have had carried out.

My argument is that the report does not take into account the other side of the door where the frame sits flush against the door frame which means that there are no gaps.

I understand that this is an issue when it is double doors as there is no frame down the middle to create a barrier/seal but as the gaps are on the outer edge which sits against the door frame there is no gap on the other side to allow smoke in.

Can you advise if in this instance i still need to adjust the doors. 

Thanks 

Zak

[Neil ashdown]

The maximum gap may well be a concern because where the gap is excessive the fire performance of the door may be compromised. 

The fire risk assessment should identify the fire doors most critical to the fire strategy at the building and these doors should be prioritised where remedial works are deemed necessary.

[Guest TomMH47a]

Hi, I'm currently working on a scheme where we have circa 400 apartments over a high rise building. The apartment entrance doors have been surveyed for the perimeter gaps by the C.O.W and they are stating that over 50% are out of tolerance (sides mainly). We have surveyed these and there are a couple that are 5mm + which are being addressed. There are however some that are more questionable i.e. 1.5mm / 4.5mm (4mm packer fits 5mm packer doesn't) any idea if this 1/2 mm would leave the doors non-compliant or as its a recommendation can a little bit of common sense be employed?

 

Thanks

 

tom 

[Neil ashdown]

The standard for timber-based fire doors is BS 8214 and section 9.5.2 says:  "Failure of fire resisting doors under test is very often due to burn-through at the operating gap between the door leaf edge and the door frame. A typical gap to achieve good fire performance is between 2mm and 4mm".    So the question is: can you justify acceptance of gaps of slightly more than 4mm?

1) Are you happy to make a note in your Fire Risk Assessment that the fire doors have been inspected and that some of the gaps are non-compliant, but that you find this acceptable in certain circumstances?

2) Has the C.O.W. checked that the cold smoke seals are effective? An excessive gap will affect the smoke restriction performance of some types of cold smoke seal. 

3) Could such non-compliancies have any impact on the safety of persons at the building in a fire?

Post-Grenfell some flat entrance doors were tested by the Government and found to fail at 15 minutes rather than the required 30 minutes. This non-compliance was considered sufficient for the government to require that some fire door manufacturers cease production until further investigations were completed.

 

[Guest Colin]

Hi Neil 

we are a certified company for installation and maintenance on fire doors. However we have been in contact with Iur 3rd party insurers and I couldn’t get an answer to the following.

its regarding drop dow seals to FD30S doors. I have read the best code of practice and this question refits to note 1 section 12.3
Am I correct in the understanding of the last paragraph of this where it states that gaps to bottom of doors may not be known untill to lime of installation.

im trying to find out if we are responsible for gaps which are over 3 mm and up to 15 mm after finding out that the floor levels ranged from 0 - 15 mm out of level.

at the time of quoting we quoted for FD30s and provided an Ironmongery scheduled which did not shot any drop down seals.

in my view at the time of rendering were were not expected to know of differing floor levels.

we have really been struggling to find someone to give us a clear yes or no.

have you any idea on this or could you point me in the right direction to who can give clear advise on this.

colin

[Neil ashdown]

The guidance document BS 8214: 2016 'Timber-based fire door assemblies-Code of practice' deals with threshold gaps for restricted cold smoke spread requirements in section 12.3. 

So its clear that, when installing fire doors to that standard, the door bottom edge to floor covering/threshold plate gap should not exceed that specified by the fire door leaf manufacturer, this is commonly 6mm to 10mm.    

Where the door is required to restrict spread of cold smoke the threshold gap should not exceed 3mm.  Where a 3mm gap cannot be achieved (due to floor condition) a suitable threshold plate or ramp should be fitted to the floor and/or a threshold seal to the door leaf as necessary.

In terms of responsibility, its impossible to answer your question because details of the agreement between you and your client are unknown.  Eg. Who carried out the pre-works survey?

In my view, the fire door installer should inform the client about threshold gap requirements and recommend suitable solutions (as described above) where gaps are excessive. Hope this helps.

[Guest Alan]

When measuring gap at the top would you take into consideration the rebate thus restricting the smoke ?

[Neil ashdown]

When inspecting the gaps between the edges of the fire door leaf and the door frame:

1) Check the gap is between 2mm minimum and 4mm maximum, generally (consult the door leaf data sheet for certainty about the requirements).

2) Ensure that the smoke seal brush or blade (where required) is in light contact with the surface that it sweeps or compresses against, in the door fully-closed position.

3) Ensure that the door leaf does no stand proud of the door frame (and not proud of the other leaf of double doors).

The door frame rebate does not provide significant protection against the spread of cold smoke, therefore smoke seals should be fitted where smoke protection is necessary.

[Guest Chris]

Hi Neil, looking for some advice if you can provide. We have recently moved some staff into a rented office space. I have attended site to review fire precautions in place and certain fire doors have a top gap exceeding 10 mm. Is 2 mm to 4 mm the acceptable range for the top gap as well?

[Neil ashdown]

A gap of 10mm between the edges of the door leaf and door frame is excessive, this applies at the top edge and at the vertical edges.  The Standard 'BS 8214:2016 Timber based fire door assemblies - Code of practice' states that "a typical gap to achieve good fire performance is between 2mm and 4mm". 

[Guest Jimmy]

Jimmy

hi Neil

we are currently upgrading communal timber fire doors, these are notional fd30 2xgg doors. The doors are a leaf and a half leaf which both open , the half leaf is lockable on flush bolts. We are changing over the 10mm intumescent seals to be 10mm intumescent smoke seals. The gaps on the bottom of these cross corridor doors are all less than 10mm. I do not want to fit a hardwood threshold as the building is lived in by mostly older vulnerable people, drop seals are only tested on single doors, we can not lip the bottom of the doors as the floors run out. As the doors are having smoke seals added does the threshold gap now have to be 3mm, 
thank you for any guidance you can give.

jimmy

[Neil ashdown]

In order to be compliant with 'BS 8214: 2016 Timber-based fire door assemblies - Code of practice' in terms of restricted smoke spread a suitable threshold seal is required. If this is not possible the maximum gap should be 3mm.

Would a Part M compliant ramped threshold plate fitted in conjunction with a static threshold seal be acceptable in respect of the 'older vulnerable people'?  See below:

[Guest johnR]

we are just about to sign off on some renovation work where a double fire door has been fitted. where the two doors meet there is a visible gap, less than 4mm, would this be acceptable?

[Neil ashdown]

In terms of fire resistance performance, BS 8214: 2016 guidance states that such a gap should generally be between 2mm and 4mm but you should check the fire door leaf manufacturers installation data sheet to see what is required.

In terms of restricted cold smoke spread, one would expect to see such a gap sealed with a combined intumescent fire and smoke seal.  Or if the meeting edges have a rebate or astragal, a bat wing type or compression type  smoke/acoustic seal.