distance flue to edge of brickwork

[chrishutt]

Numpty has gave the right answer as he is the only one to put "subject to M I`s . Most say 150mm to opening in fabric but some give different distances

I don't see how manufacturers can give different figures for the necessary clearance from a 100+mm hole to the edge of a structural opening. A hole is a hole, irrespective of what make of flue you stick though it, and there can only be one valid figure for the clearance.

I think some of you (even simond!) are still confusing clearance to structural openings with clearance to ventilation openings. Vaillant MIs refer to the 150mm figure for structural openings.

 

[twgas]

Te hole for a fanned flue should be 150mm from edge of brickwork, a balanced flue should be 300mm.

 

[bengasman]

Te hole for a fanned flue should be 150mm from edge of brickwork, a balanced flue should be 300mm.

how so??

 

[nickso]

Te hole for a fanned flue should be 150mm from edge of brickwork, a balanced flue should be 300mm.

how so??

likewise, i dont remember any distinction between the two.

 

[chrishutt]

It's because the hole for a natural draught balance flue is very much bigger than for a 100mm flue/air duct. It would require more clearance to avoid weakening the structure of the opening, so 300mm sounds about right.

 

[numpty1]

It's because the hole for a natural draught balance flue is very much bigger than for a 100mm flue/air duct. It would require more clearance to avoid weakening the structure of the opening, so 300mm sounds about right.

chris has got it spot on 300mm min from an opening[mi's] for a balanced flue again mi's need to be read.average bf measures at least 10"across by 10" some are well over 12" or more subject to boiler output.again you need to be careful of internal and external corners with bf appliances normally min 300mm some have to be 600mm.whereas a fan flue can go within 25mm of corners again subject to mi.hope this helps

 

[simond]

I think some of you (even simond!) are still confusing clearance to structural openings with clearance to ventilation openings. Vaillant MIs refer to the 150mm figure for structural openings.

I know being pedantic is a pain, but your post prompted me to check the Vaillant VTK instructions. I didn't want to get my surveys wrong .

Fitment of a VTK allows the actual concentric to terminate within 50mm of a window opening or 25mm of an airbrick . I didn't see any reference to structurals.

At the end of the day I expect most manufacturers would like the installer to take the rap on whether a flue aperture adversely affects the structural integrity of a building. If the manufacturers were overly prescriptive in this respect, their manuals would be twice the size, and they would be leaving themselves open to damage claims.

 

[nickso]

I think some of you (even simond!) are still confusing clearance to structural openings with clearance to ventilation openings. Vaillant MIs refer to the 150mm figure for structural openings.

I know being pedantic is a pain, but your post prompted me to check the Vaillant VTK instructions. I didn't want to get my surveys wrong .

Fitment of a VTK allows the actual concentric to terminate within 50mm of a window opening or 25mm of an airbrick . I didn't see any reference to structurals.

At the end of the day I expect most manufacturers would like the installer to take the rap on whether a flue aperture adversely affects the structural integrity of a building. If the manufacturers were overly prescriptive in this respect, their manuals would be twice the size, and they would be leaving themselves open to damage claims.

and this is why most mi's dont mention it. therefore you go by the regs which state 150mm for all flue types as far as i was aware. if someone has a link for a reg stating differently id be happy to be proved wrong.

 

[simond]

You don't have to go by the regs, as we all know they are overruled by the manufacturer instructions. The Regs haven't changed (although word has it they will to reflect plume management issues).

Therefore a Vaillant flue can go 50mm from a window opening, because they expressly say so.

At the moment there is no reg other than the regs saying MIs take preference, which is all we need to put a Vaillant flue 50mm from a window. CORGI therefore are happy, we comply with Building Regs, lovely day

 

[numpty1]

in absence of the mi's you apply the regs.so some poor sod who has lost the book will end up worrying over a wrongly classified install,and the installer will look a right plonker in the eyes of the customer

 

[bengasman]

chris has got it spot on 300mm min from an opening[mi's] for a balanced flue again mi's need to be read.average bf measures at least 10"across by 10" some are well over 12" or more subject to boiler output.again you need to be careful of internal and external corners with bf appliances normally min 300mm some have to be 600mm.whereas a fan flue can go within 25mm of corners again subject to mi.hope this helps

Sorry mate but you have not read my post correctly, I am trying to find the distance to end of brickwork, NOT to ventilation openings; that is what the whole post is about.

Ventilation openings are really very easy, read the MI as it supersedes gsiur.

 

[chrishutt]

You don't have to go by the regs, as we all know they are overruled by the manufacturer instructions.

Not so, Simon. Regulations (Gas Safety, Building, Water, etc.) are the law and cannot be overruled by anything. Perhaps you are thinking of Standards (BS, COPs, etc.) which are advisory and can be overruled by MIs.

I suspect that the 150mm figure is advisory and from a British Standard but if you choose to ignore it and cause some structural problem on a building you may find yourself with little defence if a claim is made against you.

In the case of Vaillant, if their MIs are saying that a clearance of 150mm is required to a structural opening (as my recent Ecotec copy does) and the VTK instructions say minimum of 50mm to a window opening, then common sense suggests that the 150mm figure should have precedence unless it is clear that there are no structural issues (e.g. the opening is near the top of a wall and bears little load).

 

[Agile]

corgi inspector told me that it's 300 mm to the reveal of any opening window, even if the opening is on the other side.

Even the CORGI inspector got it wrong then!

The official CORGI answer is that its 300 mm from any window reveal "because the windows can be changed to an opening type in the future"!

But apparently they will also say only 300 mm from an extract fan outlet. "Because its a powered outlet AND the vent is covered by closeable slats when the fans not powered". I see that as a bit too ideal!

It seems more difficult to get a figure from a ventilation INLET. I always thought 600 mm but its more difficult to find any very useful references even on most MI.

Many MI for fanned flues are still quoting figures which were used for natural draught balanced flues.

The Worcester flue MI is amusing! 300 mm spacing from their standard flue but jumps to 600 mm if you use their plume management kit.

WHATEVER you use it must not cause annoyance or danger!!!

Tony

 

[sooey]

The official CORGI answer is that its 300 mm from any window reveal "because the windows can be changed to an opening type in the future"!

Yes Tony, thinking about it now that's probably what he said.

 

[twgas]

Sorry mate but you have not read my post correctly, I am trying to find the distance to end of brickwork, NOT to ventilation openings; that is what the whole post is about.

this is why I gave measurements I did