How close can a boiler flue be to a window?

[ryangas]

From the outside edge of the flue to the opening is the distance.

so if you measure from the center it is always from the same point which it isnt always the same point if measuring from the outside edge of the flue is it ?

 

[Halesowen1]

It means the flue is always 300mm away, doing it your way it wouldnt be would it??
Different size flues.
Going from the centre you would have to make it differnt lenghts for differnt flue sizes, plus how can you measure it correctly as the centre sticks out firther from the wall. Hence measuring on a straight line to the oputer edge of the flue.

 

[GrahamM]

The flue should be 300mm from an opening- this is standard.
You measure from the outside edge of the flue to the opening. This is the standard. It's that simple!

 

[ryangas]

it is for the poc so the center of the flue i would of thought im not saying your wrong btw if im corrected i like to know that its concrete so i know i should change the way i do things

 

[ryangas]

3 assesors have told me from the center of the flue thats why im a tad confused

 

[Mbear]

so if you measure from the center it is always from the same point which it isnt always the same point if measuring from the outside edge of the flue is it ?

Dig out an mi from a boiler. The flue term location pic always shows its arrows from the edge of the flue. The arrow doesn't start in the centre of the box (box being the flue term).

 

[ryangas]

im not sure that your correct tbh i will have to call gas safe tomorrow to clarify

 

[Halesowen1]

3 assesors have told me from the center of the flue thats why im a tad confused

Dear oh dear.

 

[ryangas]

if everyone is so sure could someone please tell me exactly what regs state word for word

 

[Halesowen1]

If you fitted a Room sealed natural draught (old square cage style) would you measure from the centre??
As these can be 300mm to the opening, the centre would be about 200mm so you are saying its Ok to fit them 100 from window??
It is the outer edge not centre.

 

[Mbear]

if everyone is so sure could someone please tell me exactly what regs state word for word

Listen mate the mi pics are quite clear. I wouldn't waste ur cash on a phone call

 

[Mbear]

If you fitted a Room sealed natural draught (old square cage style) would you measure from the centre??
As these can be 300mm to the opening, the centre would be about 200mm so you are saying its Ok to fit them 100 from window??
It is the outer edge not centre.

I agree with u on this one 100%

 

[ryangas]

it would have to be a very low kw boiler but thanks for clarifying that makes perfect sense

 

[ryangas]

this is why i came on here its always good to be corrected if it makes you a better engineer thanks guys has anyone noticed that a lot of the advice regarding boiler faults is absolute dribble

 

[GrahamM]

If you fitted a Room sealed natural draught (old square cage style) would you measure from the centre??
As these can be 300mm to the opening, the centre would be about 200mm so you are saying its Ok to fit them 100 from window??
It is the outer edge not centre.

Just bet me too it. Was just about to use that example.
Got some flues to measure in morn. Off bed.:seeya:

 

[Dannypipe]

it would have to be a very low kw boiler but thanks for clarifying that makes perfect sense

Eh? You've lost me.

 

[Dannypipe]

I must off too.

 

[ryangas]

lol natural draught room sealed flue can only be within 300 mm if rated 0-7 kw

 

[Halesowen1]

But you get the drift, it could theoretically have been like this.

 

[ryangas]

been like what lol

 

[ryangas]

u mean if what i said was right a nat draught rs flue could be 100mm away ? sorry hard day

 

[ryangas]

like the website btw halsowen

 

[Halesowen1]

Yes Ryan thats what I meant about the flue could have been 300mm away yet centre 200mm further.
Thanks for feedback on website, I have messed with it a bit so need the guy to put some things right. Do you reckon the hints page is worth keeping??

 

[Dannypipe]

Anything useful on a website is worth keeping as it helps Google optimise your site. Useful info will help your rankings.

I need to update mine with some hints and tips.

 

[ryangas]

id say its worth keeping but could be used to help your seo a lot more i play about with mine a lot and find my google rankings are pretty good

 

[ryangas]

how do u put your website link on your posts like halesowen

 

[MattWeth]

Whatever MI's say, they can't take precedence over building regs (in this case Part J Combustion appliances). It's no great surprise that MI's nearly always just reprint the relevant pages of the regs.

The pages below are taken from the latest issue of Part J. Note the horizontal distance of the flue opening from an opening window of 300mm - this is edge of opening to edge of flue.

See also Note 1:
"An opening here means an openable element such as a window, or a fixed opening such as an air vent. However, in addition, the outlet should not be any nearer than 150mm (fanned draught) or 300mm (natural draught) to an opening in the building fabric formed for the purpose of accommodating a built in element, such as a window frame"

Whatever the MI's say, they can't be less stringent than the building regs and as an installer making holes in buildings for flues, you must take account of the building regs in addition to any MI's. The regs are free to download - it's worth taking a look: Planning Portal - Part J (Heat producing appliances)

 

[Heating-eng]

3 assesors have told me from the center of the flue thats why im a tad confused

Nobody has told you this, you have misunderstood ...it it always from the outside edge and if you don,t no this simple thing you could do with a refresh course.

 

[kirkgas]

are you saying that to measure the distance of the flue from the opening you put your tape at the window edge and take it to the end of the flue and measure that distance ?

you take your measurements from the closest 2 points of the 2 things you are measuring between then any other dimension is "safer" what do you mean by "end" this end or the other end, i say the closest points which is clear (or so i thought haha)

 

[kirkgas]

if everyone is so sure could someone please tell me exactly what regs state word for word

i think you need to clarify with the 3 assessors who have given you duff info (bet you dont get an email from them saying it is centre of flue) TBH a lot of info gets clouded and once clarified you will be fine with it, and as i suggest to most gas folk 9/10 invoke common sense and you will understand as in this instance it makes no sense to take a generic safe dimension from the middle of the flue as this will make larger flues more dangerous than small ones, so always nearest to nearest dimensions, and the place to get all your flue info is BS5440-1, which im sure you can access somewhere

 

[kirkgas]

sorry to go back to this guys but think about it if you measure from the center of the flue it makes no difference what the diameter of the flue is you are always measuring from the same point

you are scarting me with this one, back to basics here:
the minimum dimension is to minimise/control if you like the amount of POC's which may get back into the building, a clever bod somewhere has said if the flue is no closer than 300mm it will be safe (a discussion for another day methinks) so you are saying that a calculated amount of POC's from a 100mm flue is xcm3 and by measuring from the centre we can work out what x is, but if you then have a 200mm flue and measure from the same place you will get the same amount of POC's being near the opening, draw a straight line down the side of an A4 sheet for the wall then draw 4 dotted lines horizontally away from the wall and mark them at 300mm, then draw a horizontal line down thro' the 300mm dotted lines, now take the scenarios we are discussing, the top one draw a 100mm dia circle at 300mm centre to the wall, the next one down draw a 200mm circle with centreline at the 300mm line then the third one down draw a 100mm circle with the inner edge touching the 300mm line, then on the fourth draw a 200mm circle with the inner edge touching the 300mm line, then see if this makes sense and hopefully it will clear up your misconception on whether it matters what size the flue is when you do it from the centre (and therefore why it is wrong) and by my reckoning measuring from inner edge of ANY circle means every one of my flues conforms

 

[Halesowen1]

I think he knows now.

 

[stevetheplumber]

Whatever MI's say, they can't take precedence over building regs (in this case Part J Combustion appliances). It's no great surprise that MI's nearly always just reprint the relevant pages of the regs.

The pages below are taken from the latest issue of Part J. Note the horizontal distance of the flue opening from an opening window of 300mm - this is edge of opening to edge of flue.

See also Note 1:
"An opening here means an openable element such as a window, or a fixed opening such as an air vent. However, in addition, the outlet should not be any nearer than 150mm (fanned draught) or 300mm (natural draught) to an opening in the building fabric formed for the purpose of accommodating a built in element, such as a window frame"

Whatever the MI's say, they can't be less stringent than the building regs and as an installer making holes in buildings for flues, you must take account of the building regs in addition to any MI's. The regs are free to download - it's worth taking a look: Planning Portal - Part J (Heat producing appliances)

View attachment 4961View attachment 4962

as i understand it mi' over rule everything building regs get changed at long intervals new products get tested and approved daily

 

[MattWeth]

as i understand it mi' over rule everything building regs get changed at long intervals new products get tested and approved daily

Your council building control officer won't give a monkeys what MI's say - he'll inspect against Part J unless Part J refers to MI's or other standards (which happens only in very rare circumstances - height of flue openings above roof intersection being an example).

In the end it doesn't really make much difference as MI's will never specify a more lenient dimension (they use the regs as their baseline when writing their own instructions and they will include a statement such as 'these dimensions comply with current building regulations').

Ultimately however, the current building regs take precedence over MI's

 

[kirkgas]

looking through the IUP they state the following as the chain of command for info compliance

H&S at work act
GSI&UR
Building standards or regs
specific MI
relevant BS docs
other industry codes of practice etc