Minimum diameter for cooker extractor pipe

Clive Long,UK

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Nov 30, 2003, 12:48:11 PM11/30/03

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Hi,

I am going to be hiring a core drill, 6 inch diameter to "pop" a
ventilator through a wall. While I am hiring the baby my thoughts turn
to "popping" a vent above the cooker extractor that currently blows
back into the kitchen and gives me a cold breeze down my neck.

So, what's the minimum diameter whole I need for the cooker hood
vent? I want to keep the hole as small as possible (2-inch?) since the
rash of holes in the wall due to installation of combination boiler
flues make me worry for the wall's structural integrity.

Clive

BillR

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Nov 30, 2003, 2:31:29 PM11/30/03

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50mm (2 inch) nothing like big enough. 150mm (6") would be more like it.

Gary

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Nov 30, 2003, 3:00:02 PM11/30/03

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BillR scribbled :

> 50mm (2 inch) nothing like big enough. 150mm (6") would be more like
> it.

My Neff extractor had a 5" (125mm) outlet on top to which I ran 5" flexible
ducting to a vent.

--
Gary
Please remove #NOSPAM# if replying via email

PoP

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Nov 30, 2003, 3:33:57 PM11/30/03

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On Sun, 30 Nov 2003 19:31:29 -0000, "BillR" <send.s...@hotmail.com>
wrote:

>50mm (2 inch) nothing like big enough. 150mm (6") would be more like it.

Plastic cooker hood venting tube is usually 100mm diameter (a
rectangular section of appropriate dimensions is also available).
You'd normally drill a hole of 110mm or 117mm to put the tube through
- 150mm is going to be rather large!

Not forgetting that when you drill a large hole in brickwork I would
assume it weakens the structure. How much (or little) of a problem
that actually is I wouldn't know - but to be on the safe side I would
always plump for the smallest hole possible, especially if it is a
load bearing wall.

PoP

Bill Gardener

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Dec 1, 2003, 6:45:01 AM12/1/03

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> Not forgetting that when you drill a large hole in brickwork I would
> assume it weakens the structure.

I would be interested in hearing what the experts think of this as I have
just installed a Bosch cooker hood which required a 150mm hole through the
outside wall.

Does a 150mm hole really affect the walls structural integrity???

Thanks,

Bill

BillR

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Dec 1, 2003, 11:53:25 AM12/1/03

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As most kitchen extractor fans require a 150mm hole (as opposed to toilet
fans which are 100mm) I would hope not.
About the same as removing a standard brick?

PoP

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Dec 1, 2003, 11:25:16 AM12/1/03

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On Mon, 1 Dec 2003 11:45:01 -0000, "Bill Gardener" <b...@hotmail.com>
wrote:

>I would be interested in hearing what the experts think of this as I have
>just installed a Bosch cooker hood which required a 150mm hole through the
>outside wall.

Please bear in mind that this isn't something I'm clued up about - I'm
just working on the principle that a "whole" wall without a hole in it
might be a bit stronger than a "whole" wall with a bit missing :)

>Does a 150mm hole really affect the walls structural integrity???

I'm interested to know the answer too!

PoP

Clive Long,UK

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Dec 1, 2003, 1:26:21 PM12/1/03

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Bill

My concern is not a single hole in a wall, I'm sure the circular
profile helps distribute the load around the hole, the concern is when
the wall already has 4 x 150 mm core drilled holes within, say, 5
metres of each other

Clive

"Bill Gardener" <b...@hotmail.com> wrote in message news:<3fcb29bd$0$13347$cc9e...@news-text.dial.pipex.com>...

Brian S Gray

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Dec 1, 2003, 5:42:16 PM12/1/03

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On 1 Dec 2003 10:26:21 -0800, clive...@yahoo.com (Clive Long,UK)
wrote:

Domus produce a catalogue in .pdf form which you can download from
their website (sorry I have mislaid the URL) and which includes a
section on how you calculate what you require. I think the manual
that comes with a cooker hood tells you the flow rate required and how
the internal fan performs against various flow resistances.