Lesgrandepotato Posted December 15, 2017 Share Posted December 15, 2017 So we are close to getting BR sign off, just wondering if we have a hurdle or not, the Kitchen (which is part of a large open plan space) circa 80sqm and in places double height does not currently have an extractor and I don't really want one... We could fit the cover plates for the extractor inside and out and hope no one asks for a test... claim the extractor is on order and plead clemency. Or we could see if we actually need one? Does a kitchen have to have an extractor? even if its not enclosed? Link to comment Share on other sites More sharing options...
Bitpipe Posted December 15, 2017 Share Posted December 15, 2017 You need to look at part F and satisfy BC that you have adequate ventilation for each part of the house depending on your system (mvhr or more traditional methods). You can always take a risk and bluff but depends on your inspector! Link to comment Share on other sites More sharing options...
ProDave Posted December 15, 2017 Share Posted December 15, 2017 Remember if you just have a vent on the wall or ceiling, it needs to be a higher extraction rate than if it were a cooker hood. My neighbour realised on the day of the cmpletion insprction he didn't have an extractor in the utility room, so he cut a hole in the PB and "fitted" one. It was not wired and there was no hole in the wall, but it passed. I do have some sympathy as that was the one extractor in our last house that we never ever used,. and being forced to have it just made a 4" hole in the wall for no practical reason. Link to comment Share on other sites More sharing options...
Lesgrandepotato Posted December 15, 2017 Author Share Posted December 15, 2017 Cheers chaps - I think! because we are a renovation and no ventilation was present before, then we are not obliged to fit. (I do have a power in the wall and isolators for this purpose in place through!) Link to comment Share on other sites More sharing options...
TheMitchells Posted December 15, 2017 Share Posted December 15, 2017 We have one in our renovation house kitchen and it lets a howling gale in so I have shoved a piece of toweling into the tube to block it up. there is plenty of other ventilation, including the hob extractor. When we sell the place, i shall tell them or take it out. Link to comment Share on other sites More sharing options...
JamesP Posted December 15, 2017 Share Posted December 15, 2017 (edited) @ProDave, @Bitpipe. Can you give advice, we have a large vaulted kitchen and I don't want to fit a hob extractor. Could fit an extractor on wall opposite hob. What is the ventilation rate required? MVHR will be fitted throughout. Continuous extract says 13 l/s for kitchen, 60 l/s for intermittent extract elsewhere then its 29 l/s for 5 bed dwelling then in Notes : a. 0.3 l/s per sqm which would be 90 l/s. Bit confused. Very. Edited December 15, 2017 by JamesP Link to comment Share on other sites More sharing options...
ProDave Posted December 15, 2017 Share Posted December 15, 2017 The 13l/s is with the mvhr on boost setting. The whole house rate is 29l/s with the mvhr on normal trickle rate. Link to comment Share on other sites More sharing options...
Bitpipe Posted December 16, 2017 Share Posted December 16, 2017 12 hours ago, JamesP said: @ProDave, @Bitpipe. Can you give advice, we have a large vaulted kitchen and I don't want to fit a hob extractor. Could fit an extractor on wall opposite hob. What is the ventilation rate required? MVHR will be fitted throughout. Continuous extract says 13 l/s for kitchen, 60 l/s for intermittent extract elsewhere then its 29 l/s for 5 bed dwelling then in Notes : a. 0.3 l/s per sqm which would be 90 l/s. Bit confused. Very. Go read the MVHR threads as well as the MVHR anemometer hire threads. The design principals are pretty straightforward. Have an extract in every wet/smelly room i.e. bathrooms, cloaks, ensuite, utility & kitchen (you may need two if it's a large space). Have a supply in every other habitable room. Position these so you get the best possible cross flow of air through a room. Allow 7600mm2 gaps under doors (i.e. 10mm on a standard 760mm door). Try to locate MVHR unit so that you minimise very short or very long runs - helps with balancing later. You also need to try and get intake and extract on the same face of the house to avoid unbalancing due to external wind. It'd a bit of a compromise all round (mine is in basement so I break the even duct run rule), plus minimise the external duct runs as these need to be insulated and are larger diameter (ours 180mm) so harder to route. Plan ahead for duct runs, even with 75mm duct, bend radii are can be large and when you have a lot of ducts coming together it can get quite tricky. Balancing is all about satisfying three separate conditions - Min extract on boost for kitchen, bath and cloak rooms (on boost) - this is normally pretty easy. Balancing supply and extract - bit trickier, involves lots of running around and tweaking each vent. Whole house ventilation rate - this is calculated on your floor area and for large houses can be tricky. You need to show BC that your system can meet this req (normally by cranking up the fan speeds) but most of us here seem to run the system at a lower rate with no ill effects. Link to comment Share on other sites More sharing options...
JamesP Posted December 17, 2017 Share Posted December 17, 2017 Thanks @ProDave , @Bitpipe Link to comment Share on other sites More sharing options...
Jilly Posted February 1, 2022 Share Posted February 1, 2022 Just resurrecting this thread. I've just realised that a kitchen extractor is likely to send its extracted air up into the cold roof via the eaves, due to the overhang ? on the wall I have chosen for the hob, so would quite like to not have one and rely on a dehumidifier (or window (no MVHR here). Does anyone know of a cheap vented hob, as this might be a workaround? But they are so expensive...As its a conversion might I get more leniency from BC? Any other ideas? Link to comment Share on other sites More sharing options...
CharlieKLP Posted February 1, 2022 Share Posted February 1, 2022 (edited) The ikea one is £1370, is that too expensive? Its built into the hob so if you already have that it’s not right. im not sure what you mean though, would this work for you: https://modernlivingdirect.co.uk/Online-Store/product-details/Hendrix-100-x-70cm-Ceiling-Hood-with-Inline-Motor-AU-HENDRIX.htm?gclid=Cj0KCQiA0eOPBhCGARIsAFIwTs71ebChPgdDQ85Q9qgcOprl-2tpkVHAdGymkMoxQK7Y8_0XBlvi3dEaAk2yEALw_wcB Is the section of your kitchen causing the difficulty? Edited February 1, 2022 by CharlieKLP 1 Link to comment Share on other sites More sharing options...
Jilly Posted February 1, 2022 Share Posted February 1, 2022 Ouch, both are a bit expensive at the moment. I'm badly running over budget. The hob is to be on the wall which has a sloping vaulted ceiling with a cold roof and linear eaves ventilation. There is a very deep soffit and so a hole through the wall vent would send the warm humid air straight up into the eaves. A longer chimney /vent gives me a Conservation area/article 4 directive issue. Up through the vaulted ceiling and a tile vent is a big pain because I didn't think of it earlier... Do they do dehumidifying extractor fans...? Link to comment Share on other sites More sharing options...
CharlieKLP Posted February 1, 2022 Share Posted February 1, 2022 (edited) Is there a requirement for you to vent the air out, or can it be a recirculator one? and you want one that is countertop mounted I guess? Edited February 1, 2022 by CharlieKLP Link to comment Share on other sites More sharing options...
CharlieKLP Posted February 1, 2022 Share Posted February 1, 2022 https://www.thewrightbuy.co.uk/cookology/cookology-cdd600bk-60cm-downdraft-extractor-fan-recirculating-carbon-filter Cookology CDD600BK 60cm Downdraft Extractor Fan & Recirculating Carbon Filter Recirculating carbon filter included so you do not need to vent it outside Discreet, stylish & sure to impress Touch control operated Lies concealed in your worktop then rises when you touch the controls Powerful extraction rate - essential for keeping your kitchen fresh Link to comment Share on other sites More sharing options...
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