Flue classification

[plumbdoctor]

Hi guys sure we have had threads on this before but going to start a debate as I'm not 100% sure myself, flue to close to an openable window or air brick ? Condensing Worcester junior ?

 

[Millsy 82]

If no POC entering property NCS
If evidence of POC entering property ID

 

[arran197]

How close we talking? I think you just have to be sensible. If it's 25-70mm I wouldn't be too concerned, but after that I'd start to get the ar pad out.

 

[kris]

There will be a minimum distance to an openable window or door i think it's 300mm, but check MI,s

 

[kris]

25 - 70 is really close arran, I take it its terminal end of flue he's on about. ?

 

[kris]

I'd agree with Milsey if a door or windows but if air brick or open vent depending on position could be a r defo id if evidence,

 

[Millsy 82]

I'm sorry this comes up quite regular on here and I should imagine kirkgas will prob be on in a bit and confirm.

There is no AR it is either NCS or ID depending on fumes entering property.

 

[GrahamM]

I'm sorry this comes up quite regular on here and I should imagine kirkgas will prob be on in a bit and confirm.

There is no AR it is either NCS or ID depending on fumes entering property.

Agreed.
If standard flue too close to opening window (probably <300mm) then it's NCS.
Also remember must at least 150mm from fabric of building- sometimes forgotten!

If you know its too close and flue gases are entering property then it is an obvious ID.
This is where it gets complicated, as 5 mins later, after change in wind direction it is back to NCS.....although a properly fitted flue may also result in some flue gasses entering property under certain conditions.
This is when a judgement call and your professional experience comes in to play. Plume kit, replace window with non-opening, move boiler etc....etc...

 

[AWheating]

the question should be what do you need to do to cover your starfish.

 

[arran197]

25 - 70 is really close arran, I take it its terminal end of flue he's on about. ?

Sorry, didn't make that very clear, if it's 25-70 mm closer than the manufacturer states, so if the minimum is 300 and the actual distance is 275mm for example.

Having a look in the unsafe situations book it is either ncs or ID. Depending on if the combustion products are entering the property with a co level of 10 ppm max.

Having said that, I think it's a judgement call, even if there's no combustion products entering and the flue is obviously too close I'd still be tempted to issue an AR. Like has been said, if the wind changed direction it could become an issue.