Fire Door Alterations

[Lee Baker]

Good afternoon

I have a few burning queries that seem to play on my mind regarding upgrading and repairing of existing fire doors. Speaking to many people in passing, it appears people interpret what should or shouldn't be done differently. 

Query 1:

Upgrading a fire door where gaps to the bottom of the door is more than 8mm. 

We get asked to install hardwood lipping to the base or sides of doors where gaps exceed the allowance stated in the regulations. I always understood that it is very difficult or hard to gather any test evidence for "retro fitting" lipping to an existing Fire Door, unless you are aware of the manufacturer of door and can get written approval and have test data to prove it is allowed is installed as per the manufacturers recommendations. If you cannot obtain this, then as the installer / contractor, we cannot guarantee or prove its fire resistance, therefore we cannot or should not certify the work.

Is this correct? 

Query 2:

Vents within FD30s / FD60s doors.

From time to time we have been asked by surveyors to install an intumescent vent into an existing fire door. These doors serve the riser cupboards in blocks of flats. The surveyor states due to gas regulations, we have to allow ventilation into the riser due to the gas feed pipes?! 

My issue again, so I understood is that 1: We are damaging the integrity of any fire door if we decide to cut a large opening out to install a vent. 2: Installing an intumescent vent into a FD30(S) will not stop the passing of smoke onto the escape route (Communal corridor) before the intumescent starts to react and close, therefore causing a smoke issue on the escape route. The only option would be an electrical mechanically operated vent on the door.

Thank you in advance for your assistance

 

[Tom Sutton]

There are two links you should study https://www.asdma.com/knowledge-centre/  and https://www.safelincs.co.uk/blog/2013/08/09/gaps-underneath-fire-doors/.

Query 1. 

Based on a FAQ from TRADA for FD30 fire doors.

The recommended leaf edge to frame gap specified in BS 8214: 1990 is 4mm on all edges. Intumescent seals are engineered to react within this size of gap to give optimum sealing and clamping performance.

It is through extensive testing of fire rated doorsets, together with knowledge of the pressure regime within a fire test that a larger gap is permitted at the threshold of the door. There is negative pressure at the threshold during test conditions and so cool air is drawn in underneath the door. It is for this reason that there is unlikely to be a failure at the threshold and also why there is no need to fit a perimeter intumescent strip at this location (doorsets below FD60 performance). A larger gap at the threshold is also useful from a practical end use application for accommodating floor coverings. We recommend a gap of 10 mm from the bottom of the leaf to the structural surround.

 FD30s doors are a different matter because a 10mm gap at the threshold does not provide a passage for fire through the door however it would allow cold smoke in the early stages of a fire to pass through the door consequently you must fit cold seals to all sides of the door including the threshold,( if it is more than 4mm) or you could fit threshold cold smoke seals or lippings if you prefer. 

Query 2.

You are quite correct intumescent vent into an existing fire door is not acceptable it would have to be a 30/60 FR smoke controlled vent.

Check out http://www.sealmaster.co.uk/fire-door-seals/fire-door-seals-pages/60-minute-fire-smoke-vents.php

[Lee Baker]

Many thanks for that reply. That has certainly helped me a lot and also reassured my own thoughts and understanding.

 

So to clarify with Query 1, on FD30 doors, installing hardwood lipping should be acceptable and deemed an improvement to a door not ideally suitable due to the large gap and I can be fairly confident is certifying these alterations?

We are being approached more and more regarding upgrading "Fire Doors". I state Fire Doors in this way because I cannot guarantee or evidence these are, neither can the client. these doors are installed in residential blocks of flats and have been installed for over 15 years, more coats of paint on that are in a tin from Dulux!! We often come across these doors that have the tell take signs. Solid, Heavy, 44mm, Hardwood, however no manufacturers markings, most ironmongery installed do not comply. We stand by replacing all doors and frames for new sets, not replacing a frame or a door separate as these are not tested together. Again, I thought this was correct but I have been questioned on it.

All these queries I try to argue and stand by, but after sometime of people knocking and questioning, I start doubting myself...

[Tom Sutton]

You cannot certify any alterations, only a testing house can certify fire doors, you can say in your opinion that the door will achieve the required standard and it is up to the enforcing authority to accept it or reject it. Enforcing officers sometimes will accept below acceptable standards other times they will only accept copper plate solutions, there is no way of knowing.

1.       Fitting a certified fire door set is the best solution and bound to be accepted in all situations.

2.       Fitting a bespoke door set that has been constructed to a global assessment is possible the next best solution and is likely to be accepted in most situations.

3.       Modifying or repairing a fire door to a high standard, to produce a nominal fire door is probably the least likely to be accepted but is in many cases satisfactory.

At the end of the day it is all up to the enforcing officer what he/she is prepared to accept. If I was replacing a fire door I would use solution 1 or 2 and if I was maintaining fire doors I would use 3.

If the doors appear to be fire doors I would have them accessed by some body like the FDIS and if they are acceptable then fit the correct door furniture suitable for FD30 doors 

https://www.firesafe.org.uk/fire-doors/    http://fdis.co.uk/