Viewing 9 posts - 1 through 9 (of 9 total)
  • Rigid 150mm cooker hood ducting – WHERE???
  • squirrelking
    Free Member

    So, I give up. Where in the name of all that is holy do I get this stuff?

    Background – I went to connect up the nice new cooker hood and discovered that the builder (joiner actually) kindly fitted 100mm PVC tumble drier ducting for us to connect to. Manual states 120mm minimum with 150mm recommended.

    Wanting to do this properly I went on a quest to find 150mm ducting. As per recommendations pertaining to grease deposits I opted for rigid ducting. That and the fact that the existing ducting has been run above the ceiling where there is no access. Woo-flipping-hoo. I have since discovered that 150mm ducting is nigh on impossible to source outside of trade or industrial suppliers save for piddling little 350mm lengths. I did find one place that supplied self extinguishing PVC pipe in sensible lengths but the couplings were made out of less sensible polystyrene. I found a place that does metal but that having a huge conductor into the void space seems like a great way to lose heat out the rest of the kitchen (when the hood is off obviously).

    So I ask this:

    Does anyone know of where I may find 150mm rigid ducting (with sensible connectors) that is either insulated or easily capable of being insulated along its length? Or am I overthinking this and being too picky?

    slackalice
    Free Member

    You’re being too picky.

    100mm should be fine, unless of course you’ve gone and got yourself a commercial cooker hood, in which case, keep looking.

    Have you checked what diameter the outlet is on the hood? Do you have an adaptor or reducer available to take it to any of the standard or non-standard diameters?

    wrightyson
    Free Member

    Just get a 3m lengths of 150mm underground pipe and collars if you’re that desperate for 6 inch 😉 Ie drainage. However as above 100mm is plenty. The “150” mm probably (this may not be true) refers to a flexible type duct where you may lose flow due to kinks/waveyness in the pipe.

    Fresh Goods Friday 696: The Middling Edition

    Fresh Goods Friday 696: The Middlin...
    Latest Singletrack Videos
    spooky_b329
    Full Member

    You’re being picky 🙂

    Metal going into ceiling isn’t going to lose you a load of heat, especially if you lay the loft insulation over the top. Lets not forget you are intending to pump out several room changes worth of warm air each time you use the hood.

    Fireproof plastic with not so fire safe connectors should be OK, you say polystyrene but I’m sure its a rigid variant.

    I used something like this, http://www.ebay.co.uk/itm/Flexible-Aluminium-Air-Ducting-Ventilation-Accessory-Alloy-Vent-Tube-Hose-Duct-/141484081812?var=&hash=item20f11bc294:m:mFoBVHaTsQg3buuFJHU16GA .
    However mine was a 3 metre length and it came from one of the DIY sheds, might be 120mm though.

    Mine exhausts out of the soffit vertically downwards so I was unable to use a louvre outlet, if similar make sure you get a flap thungummy to fit inline as in windy weather my cooker hood emits a constant stream of cold air!

    squirrelking
    Free Member

    I can assure you that 100mm is not “fine” given the manufacturers instructions (which is what it gets signed off against when building control come to inspect for the completion certificate). Aside from that I’m not for burning out a £220odd hood because I’m trying to force too much air down a duct 30% smaller than the minimum diameter and 66% smaller than the recommended diameter just to save a few hours correcting a bodge job.

    Exhaust duct

    Note: The device manufacturer does not assume any warranty
    for complaints attributable to the pipe section.

    ? The device achieves its optimum performance by means of a
    short, straight exhaust air pipe and as large a pipe diameter
    as possible.

    ? As a result of long rough exhaust air pipes, many pipe bends
    or pipe diameters that are smaller than 150 mm, the optimum
    extraction performance is not achieved and fan noise is
    increased.
    ? The pipes or hoses for laying the exhaust air line must
    consist of non-combustible material.

    Round pipes

    An inner diameter of 150 mm, but at least 120 mm, is
    recommended.

    https://portal.bsh-partner.com/TCcustomBSH/controller/download_file?PDFOBID=ygljTYjcdcso0pdmdb—pYw&UMOBID=ygljTXgcdcso0pdmdb—pYw

    FWIW it’s a Neff hood to cover a 5 burner hob so nothing too exotic.

    The outlet diameter is 150mm and it comes with a 120mm adaptor. The difference boils down to how hard the fan has to work to pump the air and subsequently how loud it will be. Plus it’s about 3m of ducting all in so I need all the efficiencies I can get.

    Spooky – yeah I’ve already looked at either flaps or an integrated non return damper behind a cowl, think the cowl will be the winner! And yeah it’s rigid PS, just seems an odd combo to offer rather than the same material.

    Soil pipe is also an option as it seems to be a common fix, just not sure if it conforms to fire regs. I think I’m talking myself round to the metal if I can’t get something plastic that I know will hold up.

    qwerty
    Free Member

    I brought a single 3mtr length of 150mm ducting from a trade supplier, as ours is exposed in the kitchen I got stainless which wasn’t cheap, I’ll have a Google for you to see if I can find the supplier.

    qwerty
    Free Member

    PS: ^ that’s not where we got ours, but it is out there.

    Like me, I think you may be over thinking this, it’ll cope just fine @ 120mm and likely less, take a look at the flat tube they use in walls etc, it’s tiny in comparison.

    When building control come to sign off, i’d be very surprised if they do any more than look at the hob and the wall outside for a cover, ours did just that. I can’t see them climbing into a void with a tape measure & measuring the duct diameter. Main benefit of bigger tube is less resistance of extraction flow, they’ll all cope though.

Viewing 9 posts - 1 through 9 (of 9 total)

The topic ‘Rigid 150mm cooker hood ducting – WHERE???’ is closed to new replies.