extractor fan outlet / soil pipe distance?

Jul 27, 2015 Last reply: 5 years ago 6 Replies

Hello,



There is no obvious outlet for the fan in the en suite. There is a flexible duct behind the fan but I cannot see where it goes. I will have to get a usb camera and feed it down. My worry is it that it could be venting into the ceiling void.



I did wonder about drilling a hole through the gable end but then it occurred to me that the soil stack is on that wall. Is there a recommended distance between soil stack and fan to prevent sewer smells entering through the ducting?



Thanks, Stephen.


I had a similar concern with an existing installation, so I fitted one of these to the back of the extractor fan

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In-line back-draught shutter are also available for fitting within the ducting itself.

/I had a similar concern with an existing installation, so I fitted one of these to the back of the extractor fan

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In-line back-draught shutter are also available for fitting within the ducting itself. /Q

Not really a solution is it?

Jim K

Well, it's stopped any back draught, which used to be considerable on windy days, and opens when the fan is running. My concern about smell from the adjacent soil stack was unfounded, as the source of the smell turned out to be elsewhere.

My fan has shutters on the back already so perhaps I don't need to worry?

if the soil vent pipe termination point is within 3m or less of any opening [e.g window or extractor] then it should be at least 900mm above the highest openable part of the opening or ventilator. The pipework could be extended upwards to give this clearance or alternatively look at fitting an external [i.e frost proof ] air admittance valve [EAAV] that will let air in but not let air out thus stopping foul gas going back inside the property. Further guidance may be found on page 62 of BS EN 12056 2000 ND.3.5.6 Termination of stack vents.

That could be very helpful.

Before replying to a 5 year old post through a broken website read this first.

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