Flue in void?????????

[lame plumber]

serviced a baxi 105he on thursday, on looking at the flue which went into the wall above the boiler, but appeared outside having turned right to go out via an elbow to appear externally on the right of the boiler, this bright spark immediately thought "I cant see an inspection hatch", so up I hopped to tap on the expected hollow wall housng the elbow and joints. But to my surprise I found a very solid wall! So the installer had hacked out a wall, fitted the boiler and flue n elbow with extension, then back filled it all with cement and bricks to make good.

So it isnt in a void after all, do the joints need inspecting or do the void rules not apply as it cant leak anywhere, and the intake isnt showing any signs of leaking as no co2 present according to the fga analysis? just wondering, the last guy then rang gas safe and got the normal answer

 

[gasmanrob]

If I can't inspect all joints then in my eyes I cannot confirm that the flue system integrity and installation is complete and in safe working order. And surely it must be within a cavity if I'm reading your text correctly

 

[stevetheplumber]

no joints allowed in the wall is what ive been led to belive

 

[newcastle phill]

Think thats still classed as a void and the guidance in the TB is clear

 

[tamz]

Common sense is needed here. If you think about it every telescopic flue is effectively a joint inside a wall.
There is more risk of me catching the pox from Kylie Minogue than there is with the said flue.

 

[Deleted member 64964]

Does the wall have a cavity as this is a void and carbon monoxide can fill the cavity and leak elsewhere is the propert. Hence why this reg was updated.

 

[gasmanrob]

Common sense is needed here. If you think about it every telescopic flue is effectively a joint inside a wall.
There is more risk of me catching the pox from Kylie Minogue than there is with the said flue.

Now we can all see acknowledge and accept your sensible rational and well informed point. But as tenacious as it is manufacturers have designed a telescopic to pass through the cavity that foil tape is intrinsic to the structural integrity of the flue. But that is also the only flue joint we are allowed to tape.

If I'm in doubt I'll always air on the side of caution. If it all went wrong and a judge who had no practical skills or knowledge of my job was to pass a judgment on me using only his interpretation of the industry guidelines set out before me. How would they be likely to view it?

 

[GrahamM]

As mentioned this is a standard flue joint we are talking about. Not a taped slip joint.
If you do not have a visual to inspect integrity of the joint it is clear AR as far as I am concerned.

 

[GrahamM]

Common sense is needed here. If you think about it every telescopic flue is effectively a joint inside a wall.
There is more risk of me catching the pox from Kylie Minogue than there is with the said flue.

You should be so lucky, lucky....lucky....lucky! :lol:

 

[jtsplumbing]

You have to AR it [just to cover your backside] could be rotted away in wall

 

[newcastle phill]

You have to AR it [just to cover your backside] could be rotted away in wall

Yep. just as mortar breaks down in chimney systems and spills into bedroom spaces and lofts. The same could happen there too over years.
Not worth taking the chance...

 

[lame plumber]

bit of an update, the wall is solid, 2 to 3 foot thick, no cavities to my knowledge being stone and rubble, so cant see any joints as such. Being that the air inlet has no signs of co2 or co on testing all I could do was agree with tams succinct answer. it aint leaking, it isnt in a void and isnt a problem, just that after several different gsr reports all giving different answers, i wondered on others opinions, seems older beggars are happy to roll with it, after all even if its rotted the hole still leads outside Be different if one found co in the intake air

 

[newcastle phill]

.................roof voids ceiling voids.........(more examples).........'and any other enclosure designed to restrict access'

Id say thats any other enclosure in laymans english.
But to say it isnt a void I dont think is correct.

Its like me routing a flue through a duct or gap then thinking Hmmmmm think ill fill that gap with cement or cavity wall insulation so there isnt a gap...?????

Each to their own but with a cursory look over TB008 I do think it clearly has your definition covered in the "what is a void" section

 

[Mike Jackson]

Time to get yourself a bore scope lame. You can check the flue from inside then.

 

[lame plumber]

Time to get yourself a bore scope lame. You can check the flue from inside then.

got one, get it out to see why I find co2 in the air intake

 

[lame plumber]

.................roof voids ceiling voids.........(more examples).........'and any other enclosure designed to restrict access'

Id say thats any other enclosure in laymans english.
But to say it isnt a void I dont think is correct.

Its like me routing a flue through a duct or gap then thinking Hmmmmm think ill fill that gap with cement or cavity wall insulation so there isnt a gap...?????

Each to their own but with a cursory look over TB008 I do think it clearly has your definition covered in the "what is a void" section

have a proper read of page 2 [DLMURL]https://engineers.User PlumbersForums.net Instead - Copy the content, don't link to it.co.uk/doc/FluesInVoids/TB%20008Ed%203%20-%20Existing%20concealed%20room-sealed%20fanned-draught%20boiler%20chimney%20-%20flue%20systems%20-%201%20April%202013.pdf[/DLMURL], you'll be surprised as a void is a hollow space that could allow access to other parts by poc. I'm discussing a flue in a solid wall embedded in motar n stone, much like a chimney is build, so no risk of leaks, and as I mentioned it isnt in a void.

 

[newcastle phill]

Yeh read it lame..
Suppose it comes down to the individual interpretation, you want to believe its ok yet you ask the question..


The legal obligation is to inspect it over its entire length.
If you do that then you have met it. But you say an elbow is burried in the wall ?
Which must be inspectable from both directions...

I wouldnt class backfilling it as an impassable barrier in the case of failure and leakage of POC, much the same as a failing chimney.

 

[newcastle phill]

Be interesting to hear others views a d perhaps kirkgasses

 

[GrahamM]

As soon as you put a joint in a non-checkable area (other than a taped telescopic joint) it is going to be AR in my opinion.
As per the TB it is not permitted to have any change in flue direction/joints in an inaccessible area such as pitched roof extension so this is clear enough for me.

 

[lame plumber]

Yeh read it lame..
Suppose it comes down to the individual interpretation, you want to believe its ok yet you ask the question..


The legal obligation is to inspect it over its entire length.
If you do that then you have met it. But you say an elbow is burried in the wall ?
Which must be inspectable from both directions...

I wouldnt class backfilling it as an impassable barrier in the case of failure and leakage of POC, much the same as a failing chimney.

so now mortar is deemed to be AR even though its normal to use it in a chimney construction? Re the answer you think I want to hear, doesnt worry me either way, I have already made a decision on the install, which I am happy with on this occasion, just threw it out there to see the team discuss it

 

[stevetheplumber]

a liner in a chimney is stainless steel and designed to last the life of the appliance any flue joint in the wall is ar to me

 

[CXR100]

i would probably pass it , but the more I think of it technically the more I would want to AR it, I bet that it will definitely get into worse condition as the years pass by, as would any flue/steel pipe/copper or what have you left in mortar long enough I suppose.

 

[newcastle phill]

Edit
Type error

 

[newcastle phill]

so now mortar is deemed to be AR even though its normal to use it in a chimney construction?

Think I said it all earlier.

Anyways So long as your happy and the customer is in the clear.

 

[The Goose]

I had this at a company I used to work at. There were a block of flats, which were all the same, which had the first join sealed into the wall. Non condensing Vaillant iirc. Phoned Gas safe and they said to basically use your own judgement (the expected response). So I viewed it that if the wall is all built properly and seems sealed then in my opinion it was ntcs as not in a void. If it ever had a boiler replaced then it would have been a different story!

If you take it to extremes how about rear or side flued boilers? They cant always be inspected either.
Do all telescopic flues have tape on the joins? Similar thing there I guess too.