Adsibob Posted November 15, 2021 Share Posted November 15, 2021 What happens when a rule about venting by 7600mm2 underneath doors (eg 10mm x 760mm) conflicts with another rule about making certain doors fire doors. I thought fire doors needed intumescent strips. Do they still let enough ventilation through for MVHR (when the house is not on fire, which is the state I will aim for)? Link to comment Share on other sites More sharing options...
MJNewton Posted November 15, 2021 Share Posted November 15, 2021 I believe intumescent strips are only required on the top and sides of the door. Link to comment Share on other sites More sharing options...
Faz Posted November 15, 2021 Share Posted November 15, 2021 Indeed - side and top for FD30 doors. Smoke only comes in under the bottom of the door when it is all to late anyway! Remember you need to get FD30 frames in addition to the doors. Link to comment Share on other sites More sharing options...
Adsibob Posted January 2, 2022 Author Share Posted January 2, 2022 On 15/11/2021 at 17:00, Faz said: Indeed - side and top for FD30 doors. Smoke only comes in under the bottom of the door when it is all to late anyway! Remember you need to get FD30 frames in addition to the doors. What makes a doorframe FD30? Link to comment Share on other sites More sharing options...
Big Jimbo Posted January 2, 2022 Share Posted January 2, 2022 10 minutes ago, Adsibob said: What makes a doorframe FD30? A channel in the frame that has the fire strip thingy in Link to comment Share on other sites More sharing options...
Adsibob Posted January 2, 2022 Author Share Posted January 2, 2022 1 minute ago, Big Jimbo said: A channel in the frame that has the fire strip thingy in Yes, I'm buying intumescent strips which we will fit. But the door lining and architrave are just standard. Is that okay? Link to comment Share on other sites More sharing options...
Big Jimbo Posted January 2, 2022 Share Posted January 2, 2022 Normally there is a rebate in the frame for you to put the strip in. You might be able to router them in if your frames dont have them. Link to comment Share on other sites More sharing options...
Adsibob Posted January 2, 2022 Author Share Posted January 2, 2022 4 minutes ago, Big Jimbo said: Normally there is a rebate in the frame for you to put the strip in. You might be able to router them in if your frames dont have them. Ah, now I'm confused. I've purchased door casings like this: https://www.toolsandtimber.co.uk/oak-single-door-casing-20mm-thickness-loose-stops In addition I was going to purchase an FD30 door and the intumescent strips and architraves. I had thought all of this will combine together to make an FD30 door, but I think I'm now realising that this won't be able to conceal the intumescent strips in a rebate. Have I bought the wrong thing? Link to comment Share on other sites More sharing options...
joe90 Posted January 2, 2022 Share Posted January 2, 2022 (edited) The intumescent strips can be fitted to either the door or frame, not both, the door jam has to be larger as well. “Door stop not less than 25mm deep and 38mm wide glued and screwed to the existing doorframe at 300mm centres.” https://www.corby.gov.uk/sites/default/files/Information sheet 2 - Fire-resisting door assembly.pdf Edited January 2, 2022 by joe90 Link to comment Share on other sites More sharing options...
joe90 Posted January 2, 2022 Share Posted January 2, 2022 4 minutes ago, Adsibob said: Have I bought the wrong thing? I don’t think so but you need to get deeper door stops as posted above. Link to comment Share on other sites More sharing options...
Big Jimbo Posted January 2, 2022 Share Posted January 2, 2022 Joe is right, but IMO they look shite in the doors Link to comment Share on other sites More sharing options...
Adsibob Posted January 2, 2022 Author Share Posted January 2, 2022 I'm still learning the lingo. Presumably door stops are the strips of wood that stop the door from opening both ways? Kicking myself as I now see the same company that I've bought the door linings from also sell the same version with "loose stops". Query why they don't sell all of their door linings with loose stops. If the regs require that I have stop not less than 25mm wide and 38mm long, am I going to lose 50mm (25mm on each side) of doorway width from all of my doorways!!! Link to comment Share on other sites More sharing options...
PeterW Posted January 2, 2022 Share Posted January 2, 2022 Speak to BCO and get FD30 doors with 8mm trimmable sides then rout the doors. You can get an intumescent strip cutter from Trend, takes 5 mins. Link to comment Share on other sites More sharing options...
Adsibob Posted January 2, 2022 Author Share Posted January 2, 2022 2 minutes ago, PeterW said: Speak to BCO and get FD30 doors with 8mm trimmable sides then rout the doors. You can get an intumescent strip cutter from Trend, takes 5 mins. I'm now finding further stuff online suggesting that the 25mm thickness door stop dates back to before intumescent strips were used. Looking for a more authorative source within Approved Document B itself, but as is always the case with government produced literature, it is so badly organised taking me a bit of time to find the right section. I agree with @Big Jimbo that they will look shite if routed into the door. Although I've seen some literature online to suggest that the intumescent strips can be painted over without compromising their effectiveness. Link to comment Share on other sites More sharing options...
PeterW Posted January 2, 2022 Share Posted January 2, 2022 5 minutes ago, Adsibob said: I agree with @Big Jimbo that they will look shite if routed into the door. Although I've seen some literature online to suggest that the intumescent strips can be painted over without compromising their effectiveness. I’ll take some photos of both brown (in oak / meranti doors) and white in painted FD30 and see if you think that’s the same - you cannot see them unless you go looking. Link to comment Share on other sites More sharing options...
Adsibob Posted January 2, 2022 Author Share Posted January 2, 2022 4 minutes ago, PeterW said: I’ll take some photos of both brown (in oak / meranti doors) and white in painted FD30 and see if you think that’s the same - you cannot see them unless you go looking. Thanks @PeterW that would be much appreciated. Link to comment Share on other sites More sharing options...
Adsibob Posted January 2, 2022 Author Share Posted January 2, 2022 (edited) In other news, I got lost in Approved Document B and stumbled upon a section which seems to suggest that my expensive MVHR system installed by a reputable MVHR specialist company does not comply with building regs. Section states: Page 14 of Approved Document B (2019 edition) states: Air circulation systems 2.8 Air circulation systems which circulate air within an individual dwellinghouse with a floor more than 4.5m above ground level should meet the guidance given in paragraph 2.9. 2.9 All of the following precautions should be taken to avoid the spread of smoke and fire to the protected stairway. Transfer grilles should not be fitted in any wall, door, floor or ceiling of the stair enclosure. Any duct passing through the stair enclosure should be rigid steel. Joints between the ductwork and stair enclosure should be fire-stopped. Ventilation ducts supplying or extracting air directly to or from a protected stairway should not serve other areas as well. Any system of mechanical ventilation which recirculates air and which serves both the stair and other areas should be designed to shut down on the detection of smoke within the system. For ducted warm air heating systems, a room thermostat should be sited in the living room. It should be mounted at a height between 1370mm and 1830mm above the floor. The maximum setting should be 27°C. The system they have installed definitely does not comply with 2.9(b) because all of our ducts are plastic; and depending on the definition of "transfer grilles", the system may not comply with 2.9(a) as we definitely have an air supply vent in the stairwell. Not really sure why we have one there, but we do. Not sure about 2.9(d). A search of the Renovent Flair 400 PLUS manual for "fire" or "detect" did not bring up anything useful. I guess that could be set up as an aftermarket feature, but simply incredible that the company that have sold me this appear to have fallen very short of building regs compliance. How can that be! This is why I hate reading into building regs! Edited January 2, 2022 by Adsibob Link to comment Share on other sites More sharing options...
Faz Posted January 2, 2022 Share Posted January 2, 2022 Or just order the FD30 door from your supplier and an FD30 compliant frame and stoip from the merch. Avoids all of the reading of the mumbo jumbo. A basic understanding doesn't hurt thouh - like of you have a 150mm upstand from the garage you don't need the smoke skirt which looks shite. Link to comment Share on other sites More sharing options...
joe90 Posted January 2, 2022 Share Posted January 2, 2022 Or just ask your BCO about using what you have, I find they all interpret the rules differently!!! Link to comment Share on other sites More sharing options...
ProDave Posted January 2, 2022 Share Posted January 2, 2022 3 minutes ago, joe90 said: Or just ask your BCO about using what you have, I find they all interpret the rules differently!!! The only thing our BCO checked about fire doors was that the door to the garage had a closer. Link to comment Share on other sites More sharing options...
saveasteading Posted January 2, 2022 Share Posted January 2, 2022 Fire rated doors should have a coloured inset plug. That way the BCO can easily check it if there is any doubt. Re complex regulations. I find it best to do an old-fashioned printout of the relevant pages, go into a quiet room, magic marker the clauses that appear to be relevant and draw arrows between them. Once the logic is sorted, keep the notes for when you inevitably forget it all. This works especially well if 'discussing' with a BCO. 3 Link to comment Share on other sites More sharing options...
ProDave Posted January 2, 2022 Share Posted January 2, 2022 1 hour ago, saveasteading said: Fire rated doors should have a coloured inset plug. Howdens ones don't. The only way you can tell is they are heavier, and have a PAPER label stuck to the top. Link to comment Share on other sites More sharing options...
saveasteading Posted January 3, 2022 Share Posted January 3, 2022 4 hours ago, ProDave said: Howdens ones don't. Thanks for this. I thought it was compulsory. Just good practice but Howdens don't bother it seems. I guess the BCO can ask too see the delivery schedule, but can't lift it too see if heavy. Not a problem with self-builders doing things right , but I will now worry about some commercial situations. Link to comment Share on other sites More sharing options...
Mike Posted January 3, 2022 Share Posted January 3, 2022 On 02/01/2022 at 15:44, Adsibob said: What makes a doorframe FD30? Certification (to BS 476 : Part 22 : 1987 or BS EN 1634-1: 2014) that the combined door and lining (as a set), with appropriate ironmongery and installation methods, meets the FD30 standard. DIY mixes of doors, frames & intumescent strips don't meet the standard. Link to comment Share on other sites More sharing options...
Adsibob Posted January 3, 2022 Author Share Posted January 3, 2022 (edited) 1 hour ago, Mike said: DIY mixes of doors, frames & intumescent strips don't meet the standard. This would suggest my architect is incompetent, as he has basically suggested buying different bits and bobs from different suppliers so as to meet his conception of the design, even though he knows full well that we need FD30 compliance. Edited January 3, 2022 by Adsibob 1 Link to comment Share on other sites More sharing options...
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