Location of gas boiler flue (with a twist)

n what grounds

On whatever reasonable grounds you can present.

We've done this exact thing with flues over boundaries, when we demonstrated a controlling influence on adjacent properties or that building work would not be possible, and relaxing of the 300mm dimension to air vents and windows.

It comes down to the individual situation.

It's not about skimping, but about what is safe.
 
On what grounds? The op wants to skimp and not pay for a vertical flue or relocate?
You're not quite right there. Though I'm scratching my head a little about why you seem confrontational. Ok, if you feel the need, I guess. I'm simply not an angry person. Though there's lots of them about.

I am not wanting to scrimp at all. A vertical flue will be about 150 quid extra. If I'm short of that, I've got bigger problems. But to mount a new boiler where the existing one has been for 20 years would be easier and quicker. Hardly a hanging offence for wanting to TRY to achieve that. If it breaks regulations, then of course it will not be done. What idiot would do that?

But think of this: There is a BS standard called BS5440, Part 1, 2008. Before that there was a 2000 version. So at some point, it got updated. It got updated to add new scenarios, to correct errors, to correct typos and yes, to bring clarity in situations where wording could be misinterpreted. And a whole raft of other reasons.

If nobody ever bothered to put their thinking hats on about these things and improve on them then we'd still be back in the dark ages. So I am bothering to challenge something and no, it's not just to say 150 notes.

Remember this: The Building Regs office has looked at the document with me (their document) and agree it is unclear. Moreover, they cannot give me a straight answer one way or the other. They have said they would be ok with it, given the scenario we have here.
 
I'm sorry but I'm with Cgas on this and in fact doc J is pretty clear. it states that a flue cannot be any closer than 200mm or manufacturers instructions if greater(there is even a specific footnote regarding the MFIs) from a boundary alongside the terminal.
I will ask why you think this is? yes that's correct, it's to prevent discharge across the boundary, so why would it be allowed to discharge directly over the boundary.
The reason it's not expressly mentioned isn't because it's allowed, it's because there is no allowable distance, the minimum distance is 600mm or manufacturers instructions if greater, couldn't be clearer 0mm is definitely less than 600 mm.
I'm surprised this isn't written into the gas safe guidlines, it was explicitly written into the previous corgi ones
 
I'm sorry but I'm with Cgas on this and in fact doc J is pretty clear. it states that a flue cannot be any closer than 200mm or manufacturers instructions if greater(there is even a specific footnote regarding the MFIs) from a boundary alongside the terminal.
I will ask why you think this is? yes that's correct, it's to prevent discharge across the boundary, so why would it be allowed to discharge directly over the boundary.
The reason it's not expressly mentioned isn't because it's allowed, it's because there is no allowable distance, the minimum distance is 600mm or manufacturers instructions if greater, couldn't be clearer 0mm is definitely less than 600 mm.
I'm surprised this isn't written into the gas safe guidlines, it was explicitly written into the previous corgi ones

The manufacturer's guide takes precedence, then the GSIUR 98, then building regs (if they apply)

The principle for the requirement away from a boundary is stated in s145 of the gas regs. Adhere to that principle and flues can go where they like, and dimensions don't matter in this particular context.
 
I understand what your saying but to be fair every MFI I have seen has the same diagram and dimensions as the BRs anyway
 
Just a point of pedantry to remind all that the approved docements provide guidance on how the building regulations (the bits in green boxes near the beginnings of the documents) might be satisfied. A failure to adhere to the guidance is not necessarily a failure to comply with the regs.
 
Just a point of pedantry to remind all that the approved docements provide guidance on how the building regulations (the bits in green boxes near the beginnings of the documents) might be satisfied. A failure to adhere to the guidance is not necessarily a failure to comply with the regs.

It's fundamental not pedantic.

Many people mix up building regs with the approved documents, and will argue endlessly that the words and diagrams in those documents are how it must be done.

In the context of this thread, gas engineers argue because they don't know what the building regs actually are, and building control people argue because they don't know about gas regulations.
 
gas engineers argue because they don't know what the building regs actually are, and building control people argue because they don't know about gas regulations.
Woodbridge argues because he's a grouch until he's had his boiled eggs and soldiers.:mrgreen:
 
I'm sorry but I'm with Cgas on this and in fact doc J is pretty clear. it states that a flue cannot be any closer than 200mm or manufacturers instructions if greater(there is even a specific footnote regarding the MFIs) from a boundary alongside the terminal.
I will ask why you think this is? yes that's correct, it's to prevent discharge across the boundary, so why would it be allowed to discharge directly over the boundary.
The reason it's not expressly mentioned isn't because it's allowed, it's because there is no allowable distance, the minimum distance is 600mm or manufacturers instructions if greater, couldn't be clearer 0mm is definitely less than 600 mm.
I'm surprised this isn't written into the gas safe guidlines, it was explicitly written into the previous corgi ones
It's a bit mute now, as we've gone through the ceiling/flat roof anyway (and in doing so, are now much closer to a window, albeit on our property, than before. Therefore, it could be argued the current arrangement is less safe, but hey it now meets whatever regs are being debated).

Just to be clear though, the old way did not discharge directly over the boundary. The flue itself went through/crossed the boundary wall. I suppose it is what one's definition of "alongside the terminal" means. I would interpret that as being at something like 90 degrees, running "alongside" the terminal.

All still very annoying, since it was safe before and we all see installations (read of them on here) where a flue clearly blows across the boundary, often times onto the neighbour's property.
 
Good to hear your making progress,
Your boiler installer will have fitted the boiler as per the supplied installation and servicing instructions,the supplied installation and servicing instructions are not a guide as mentioned previously and any departure from these needs prior written approval from the boiler manufacture (have been in that situation before and its not easy).
The visible flue plume from condensing boilers could be considered a nuisance so its best to discharge away from neighbours boundary,so careful consideration to boiler position is very important these days. Your previous boiler may well have been safe,it would have been pointed out to you during annual service visits if not.
Maybe post further questions in the plumbing section here.
 
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