Making good a fire door after cutting into it

[Guest Ben]

Hi

I am enquiring about an issue I currently have the loft conversion I have recently completed. We have had to adjust the fire doors to work with the pitch of the sloping ceiling. So one side of the doo is cut and say a 42 degree angle from a third of the width of the door. Is there a product you sell or on the market which you could apply to cap the top of the door to reinstate the 30 min requirement again.

[Tom Sutton]

FD30 (30 minutes) fire doors are usually 45mm thick, as opposed to the standard door thickness of 35 mm, Most fire doors have a solid core construction which can include: particleboard, chipboard, flax board and solid timber. The assembly of a fire door can vary greatly, some have: hard wood timber framing around the core with a laminated veneer; others have a hard wood lipping (5-20mm thick) around the core with a veneer on top; and in some cases a plywood, veneer or MDF facing is glued on to the core without framing or lippings. There is no preferred construction method, as long as the desired fire rating is achieved.

A fire door must be fitted with approved intumescent strips which play a crucial part in achieving the fire door rating. When subjected to heat, the intumescent strips expand and seal the gap between the door edge and the frame. Intumescent seals can be fitted within the door frame or grooved into the door edge. Advice on the intumescent strips can be obtained from the test evidence report or a specialist company.

The material from which the door frame is constructed (e.g. softwood, hardwood or MDF), as well as its section sizes must comply with the required standards. Furthermore, essential hardware (ironmongery) must also have its’ own individual test evidence to show fitness for purpose.

So it all depends on the construction of the fire door and this can only be found by de-construction of part of the door. Then it is a case of re- constructing the part of the door that has been modified. If the fire door is a certificated door then the certificate will be void unless the work is carried out by a specialist approved by the certification scheme. If the work is carried out by a none specialist the fire door will be classed as a nominal door and you need to find out if the building control officer will accept it.

http://www.firesafe.org.uk/fire-doors/

[Guest terry draper]

So, with a fire door blank, cut to size, would the h/w lipping used to remake the edge be pinned and glued?

Terry

[Tom Sutton]

What you are proposing no matter how you fix the lippings, you would have a nominal FD 30 door but not a certified FD 30 door this is because the design has not been tested to BS 476 part 22. If you were using this door in a building project then you would have no documentation to prove its fire resistance to the building control officer. You would have to argue your case that in your opinion the nominal FD 30 door would hold a fire in check for thirty minutes, which would not be easy. You can have the door checked by a fire door assessor but it is much easier to have a piece of paper that states it’s the capabilities from a specialist.

In my opinion if you are installing new fire doors you should use certified door sets. If they are existing doors and are solid, well-fitting, you could consider keeping them, maybe upgrade them with some modifications. If you need to modify a fire door it will depend on the degree of modification small alteration could be within the scope of a good joiner more extensive changes need to be done by a specialist joiner. The problem with nominal fire doors is convincing the enforcing officers they are fit for purpose without proper documentation.

[Guest Rob]

I have FD30 fire doors and am having new carpet fitted. If I need to cut the doors down to allow for the new carpet height can I and is it best to use a hand saw or a circular saw? The carpet fitters want £50 per door and I have 4 that may need doing! ouch!

[Tom Sutton]

Most joiners would use a hand saw but what is more important is the construction of the door and how much it would be safe to remove.

[Guest Ben]

Tom I am also needing to plane down a front door which has a thin metal lip around the faces of both sides of the door, my wood flooring is catching and need to plane a few mill off the bottom how can I achieve this thank you

[Neil Ashdown MAFDI]

Hi Ben, Is it a fire door?

[Guest Interested]

Hi all, 

Been asked to add hardwood lipping to some existing fire doors in a tower block that don't fit properly so they are not within the 3mm allowed around the door, the issue i have is that they already have intumescent strips fitted with smokeseals so i obviously couldn't just go over the top, if i were to cut off the existing lipping could i then fit a new lip would it keep its fire integrity? thanks

[Tom Sutton]

Yes I would agree with you to remove the old lippings and replace them with new, however the maximum dimensions of lippings length and depth, will depend on on the size of door but the width is controlled by the fire test data/assessment which will vary depending on the test and if you do not have it, it may cause problems. Also if the fire doors are certificated  they will lose it, if you are not an approved contractor to that association. (The British Woodworking Federation or BM TRADA.) 

[Tom Sutton]

Further to my above submission you must run it past the building control to see if they will accept it, they may require fixing new fire door sets, for you to get it signed off.

[Neil ashdown]

I would advise you to contact a Certificated Fire Door Inspector.  A competent inspector would be able to come to site and inspect the fire doors and then recommend the exact method for the remedial works. There are a few methods that may be employed to reduce the perimeter gaps to within the necessary tolerances.

They would also be able to provide the details you require in their inspection report.  Once the works have been completed they could provide a second report and, if the door is by then compliant, to confirm compliance.

Clearly though, where the inspector's inspection reveals any other issues, these would also require remedial works.

Edited October 5, 2019 by Neil ashdown
To provide additional information

[Guest Sadik]

Hi all,

I need to cut to size some 30 min fire  door blanks,  and don’t know if I need to fit hardwood strip around? 

Thanks

[Neil ashdown]

All fire door blanks have a Technical Manual or Global Fire Resistance Assessment. Consult the manufacturer to obtain the documentation and follow the information therein. Different types of fire door blanks have different sizing, cutting  and lipping requirements.

[Guest Adam]

is there a benefit to lipping a fire door opposed to adding a drop down seal? 

[AnthonyB]

Lipping/rebating doors predates modern methods of sealing fire doors - it used to be common because it was the only way to get some form of flame, heat & smoke seal. Whilst it had some effect compared to a door without the rebate the performance is nowhere near the same as a door with intumescent seals and cold smoke brushes.

The acceptability of an 'older' method of fire safety joinery will depend on the situation and the performance requirements of the door-set in question - in some situations such as heritage premises and certain existing premises (based on other factors taken into account) it may be acceptable, but not if current standards are a requirement.

[Neil ashdown]

Hi Adam,

A drop seal will not be a substitute for a hardwood door lipping, in most cases.

If you are installing a new fire door the installation instructions will state the maximum gap allowed at the threshold.  This is usually somewhere between 6mm and 10mm from the bottom edge (the timber edge not the seal) of the door to the floor surface or threshold plate.  It is necessary to comply to maintain the door's fire rating.

Most fire doors are also required to provide smoke protection (at ambient temperature), in which case the maximum threshold gap is 3mm.  If 3mm cannot be achieved due to floor conditions, then a static threshold seal or drop-seal will be required to close the gap, but the gap between the door bottom edge and the floor surface must still not exceed the door manufacturers requirements (eg. 6mm to 10mm). 

If the door is not new and the specific gap requirement unknown, work on a maximum gap of 10mm for a timber-based fire door and 3mm where smoke protection is required.  If the gap is more than 10mm use a floor mounted threshold plate or suitably lip the door bottom edge with hardwood to reduce the gap accordingly.  Then add a suitable threshold seal to provide smoke protection where necessary. See image below...............

Edited June 30, 2020 by Neil ashdown
To correct typing error

[Guest Nichola Brooke]

I work in an office that spans over 3 floors with one exit stairwell. All the fire doors that run off the fire exit have gaps in excess of 4mm on each side, which exceeds the maximum fire door guidelines. The landlord is proposing we have lipping and new intumescent strips added to these fire doors by a non certified fire door carpenter, would we be in breach of fire regulations?

[Neil ashdown]

The contractor doing the remedial work to the fire doors does not have to possess any particular certification or qualifications BUT they must be COMPETENT.  Refer to Article 17 and article 18 of the fire safety order.  

http://www.legislation.gov.uk/uksi/2005/1541/article/17/made

http://www.legislation.gov.uk/uksi/2005/1541/article/18/made

[Guest Shooby]

I need to re-lip a 44mm wide solid core fire door after cutting it down according to the specifications in the certificate but I can only find 45mm wide hardwood lippings.

Neither I nor my carpenter have a lip trimmer machine (very expensive!), so how do I get rid of that extra 1mm? Do I attach lipping and then sand the surplus off or should it be planed prior to attaching? Not quite sure where to buy exactly 44mm hardwood lippings in North London.

[Neil ashdown]

Use a small hand held bottle router with a trimmer bit. Failing that sand off the surplus. Make sure you use the correct adhesive for lipping the door leaf.

[Guest jason]

Hi

 So I had a maglock removed from a fire door which has left a gap on the top where it used to be housed. Is there a specific method to repair it. Someone mentioned that the top length can be cut off and a  new section be glued and tacked on as replacing it would be very costly. How true is this as I do not want to go against regulations of fire doors.

[Neil ashdown]

The top edge of the door is potentially most vulnerable in a fire situation.  Without seeing the door and the 'gap' you mention it is impossible to say whether an effective repair might be possible.

[Guest Shooby]

On 10/07/2020 at 14:49, Neil ashdown said:

Use a small hand held bottle router with a trimmer bit. Failing that sand off the surplus. Make sure you use the correct adhesive for lipping the door leaf.

What is the correct adhesive to use please?

Plus, I have spoken to a number of tradesmen who have been fitting fire doors for over 10 years, regarding the need to re-lip a solid core fire door once it has been cut, and they basically tell me I am talking nonsense. Is re-lipping absolutely necessary? The certificate says it should be done but can a fire inspector overule the certificate and pass the door?

If the door is re-lipped with 8mm hardwood lippings along the sides (certificate says only sides need re-lipping), are the channels for intumescent strips cut into the side lippings and into top of door? Seems logical but I just wanted to be sure.

[Neil ashdown]

Contact the door leaf manufacturer to find out the adhesive requirements for that particular door type. Intumescent seals are best positioned in the door frame but it is acceptable to fit them to the door leaf edges as an alternative. 

An inspector cannot 'over-rule' product certification.