dysty42 Posted October 23, 2020 Share Posted October 23, 2020 (edited) Hi all, I'm having a slight late stage headache with my kitchen ventilation. The electrician put in a 4 inch fan and which does (max) 22l/s, I now understand I need at least 30l/s in a kitchen with intermittent ventilation. It seems you can't get a 4 inch vented intermittent fan that does 30l/s (or at least I can find one). So I was reviewing part F and noticed the continuous ventilation options. It seems that if you have continuous ventilation, a far lower rate is needed. Vent Axia do this extractor http://www.vent-axia.com/files/catdownloads/quadra 2nd edition.pdf Though it's max trickle rate still seems to be too low for a kitchen. So my question is, can anyone recommend a fan that will vent through a 4 inch/100mm hole that will pass the kitchen part F requirements? Can I just put in a low power fan with no switch and say it's continuous ventilation? Edited October 23, 2020 by dysty42 Link to comment Share on other sites More sharing options...
Ferdinand Posted October 23, 2020 Share Posted October 23, 2020 My Friday evening post-G&T-when-I -could-only-find-a-really-big-glass answer is that you could install a row of them like engines on an ecranoplan: Somebody will be along in a minute who has drink-taken less generously, and met the same issue. Reaching through the Mother's Ruin, and assuming no MVHR, I wonder whether the cooker hood (if you have one) can count as intermittent ventilation to meet the other standard, or whether the "whole house" calculation may offer a remedy. That 13 l/s continuous number in the Approved Doc looks suspiciously like a number which is designed to be just bigger than the kit normally used at some point. Another answer would be a 125 or 150mm fan or HR fan. With a backdraft shutter that would control your air leakage, and could be switched between different options later without doing further violence to your wall if you find that meets your personal requirements. (Though 2 100mm fans could be a realistic option.) I am sure that this challenge has occurred before, so I would not be worried (yet ?). A conversation with BC may help, or perhaps just not mentioning it and they may not either. Link to comment Share on other sites More sharing options...
PeterW Posted October 23, 2020 Share Posted October 23, 2020 Airflow Icon 30 will do 32l/s through a 4” duct. Nice looking unit too. https://www.tlc-direct.co.uk/Products/ADICON30.html Link to comment Share on other sites More sharing options...
dysty42 Posted October 23, 2020 Author Share Posted October 23, 2020 Yes, my dad suggested just a second 100mm fan. Could do, but would mean a hole in the wall I don't really want. Or, as you say I could got to 5/6 inches, but am worried about trying to increase the bore of my current hole, I'd have to hire a core bit/suitable drill and then I could end up making a mess of my wall if it doesn't go through cleanly. (though ultimately I may have to increase it to 150mm when I get a cooker hood) At the moment, I just want the easiest route past building control - he has visited once, gave me a list of things to do. Didn't even mention any of the extractors. The bathrooms/wc ones are fine anyway.. but then a few days ago he send me a list of required paperwork, and a flow test of the fans is included. So, the lack of blowy power on the kitchen one is likely to be picked up. I just thought this continuous venting option could be an easy escape, and from what I read.. may well use a bit less electric than intermittent extractors to boot. Appreciate your (albeit slightly inebriated) reply! Link to comment Share on other sites More sharing options...
dysty42 Posted October 23, 2020 Author Share Posted October 23, 2020 (edited) @ peter, awesome. That'd be an easy option then - so long as it will register at least 30l/s for the flow test. Part F also says it can be 30l\s rather than 60l/s if the fan is near the hob. I don't have a hob.. yet. So I guess I will just say the hob will go near the fan. Edited October 23, 2020 by dysty42 Link to comment Share on other sites More sharing options...
PeterW Posted October 23, 2020 Share Posted October 23, 2020 They don’t do flow tests to be honest - just show the spec sheet !! Link to comment Share on other sites More sharing options...
dysty42 Posted October 23, 2020 Author Share Posted October 23, 2020 The BC guy has asked for 'Extract Fan Air-Flow Test reports (BPEC registration where possible)', so I assumed I had to get a private company in to test the extractors? You recon he'd be ok with just seeing the specs of the fans used? Link to comment Share on other sites More sharing options...
PeterW Posted October 23, 2020 Share Posted October 23, 2020 Seriously ..??!! Seen that for MVHR but never a single fan test. Is this a new build and are you having an air tightness test done as they may do it at the same time as some companies offer it as an add on. Link to comment Share on other sites More sharing options...
dysty42 Posted October 23, 2020 Author Share Posted October 23, 2020 (edited) Yeah, it's just a 2 bed new build. It's got four extractors, 2 in ensuites, one in the wc and I put one in the kitchen, as I wasn't intending to sort the hob and extractor hood until after sign off. Unfortunately I've already had the air test done, if I'd known about this requirement of course I probably could have got it done at the same time. I think technically it's been a factor in part F since 2010, but yes it does seem a bit silly as the fans presumably flow as much as they are supposed to flow(they all go direct through the wall, no long ducting). I also see you can buy testing equipment quite cheap, but what he's sent me seems to suggest he wants it certified. Edited October 23, 2020 by dysty42 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now