Loft insulation and gas boiler flues.
 

This summer I had a new gas boiler installation in an airing cupboard
near the centre of the first floor. Flue goes into the loft space and
across to a gable end. Having just been up into the loft I see that the
fitters have disturbed a lot of insulation whilst installing the flue
and not bothered to put most of it back properly.

Are there any regulations about how close to gas flue pipes loft
insulation can be?

The flue pipe is plastic so presumably gets nothing more than warm.

--
Chris B (News)

Loft insulation and gas boiler flues.
 

On 13/11/2019 19:52:56, Chris B wrote:
This summer I had a new gas boiler installation in an airing cupboard
near the centre of the first floor.Â* Flue goes into the loft space and
across to a gable end.Â* Having just been up into the loft I see that the
fitters have disturbed a lot of insulation whilst installing the flue
and not bothered to put most of it back properly.

Are there any regulations about how close to gas flue pipes loft
insulation can be?

The flue pipe is plastic so presumably gets nothing more than warm.

The only rule regarding flues I'm aware of is they must be separated
from (combustible) timber by 75mm of air, or 25mm of incombustible
material. I wasn't aware of any requirements where the flue is buried in
insulation.

Loft insulation and gas boiler flues.
 

On 13/11/2019 21:25, Fredxx wrote:
On 13/11/2019 19:52:56, Chris B wrote:
This summer I had a new gas boiler installation in an airing cupboard
near the centre of the first floor.Â* Flue goes into the loft space and
across to a gable end.Â* Having just been up into the loft I see that
the fitters have disturbed a lot of insulation whilst installing the
flue and not bothered to put most of it back properly.

Are there any regulations about how close to gas flue pipes loft
insulation can be?

The flue pipe is plastic so presumably gets nothing more than warm.

The only rule regarding flues I'm aware of is they must be separated
from (combustible) timber by 75mm of air, or 25mm of incombustible
material. I wasn't aware of any requirements where the flue is buried in
insulation.

Interesting - I presume the distances from combustible materials were
defined for old-fashioned, very hot, metal flues. There would seem to be
no point in any separation at all with co-axial flues, where the outer
tube carries only ambient air; even less with co-axial flues on
condensing boilers, where even the inner, exhaust section is plastic!
Either there is something I haven't thought of or the regs are way out
of date for modern systems.

SteveW

Loft insulation and gas boiler flues.
 

On 13/11/2019 21:52:01, Steve Walker wrote:
On 13/11/2019 21:25, Fredxx wrote:
On 13/11/2019 19:52:56, Chris B wrote:
This summer I had a new gas boiler installation in an airing cupboard
near the centre of the first floor.Â* Flue goes into the loft space
and across to a gable end.Â* Having just been up into the loft I see
that the fitters have disturbed a lot of insulation whilst installing
the flue and not bothered to put most of it back properly.

Are there any regulations about how close to gas flue pipes loft
insulation can be?

The flue pipe is plastic so presumably gets nothing more than warm.

The only rule regarding flues I'm aware of is they must be separated
from (combustible) timber by 75mm of air, or 25mm of incombustible
material. I wasn't aware of any requirements where the flue is buried
in insulation.

Interesting - I presume the distances from combustible materials were
defined for old-fashioned, very hot, metal flues. There would seem to be
no point in any separation at all with co-axial flues, where the outer
tube carries only ambient air; even less with co-axial flues on
condensing boilers, where even the inner, exhaust section is plastic!
Either there is something I haven't thought of or the regs are way out
of date for modern systems.

I'm going by experience in a timber framed house. This document is useful:
https://www.igem.org.uk/_resources/a...ll/0/49955.pdf

Loft insulation and gas boiler flues.
 

On 14/11/2019 00:02, Fredxx wrote:
On 13/11/2019 21:52:01, Steve Walker wrote:
On 13/11/2019 21:25, Fredxx wrote:
On 13/11/2019 19:52:56, Chris B wrote:
This summer I had a new gas boiler installation in an airing
cupboard near the centre of the first floor.Â* Flue goes into the
loft space and across to a gable end.Â* Having just been up into the
loft I see that the fitters have disturbed a lot of insulation
whilst installing the flue and not bothered to put most of it back
properly.

Are there any regulations about how close to gas flue pipes loft
insulation can be?

The flue pipe is plastic so presumably gets nothing more than warm.

The only rule regarding flues I'm aware of is they must be separated
from (combustible) timber by 75mm of air, or 25mm of incombustible
material. I wasn't aware of any requirements where the flue is buried
in insulation.

Interesting - I presume the distances from combustible materials were
defined for old-fashioned, very hot, metal flues. There would seem to
be no point in any separation at all with co-axial flues, where the
outer tube carries only ambient air; even less with co-axial flues on
condensing boilers, where even the inner, exhaust section is plastic!
Either there is something I haven't thought of or the regs are way out
of date for modern systems.

I'm going by experience in a timber framed house. This document is useful:
Â* https://www.igem.org.uk/_resources/a...ll/0/49955.pdf

I've not had a proper look, but a quick glance seems to suggest 25mm
separation and only 10mm for a concentric flue for a boiler.

SteveW

Loft insulation and gas boiler flues.
 

On 14/11/2019 18:55, Steve Walker wrote:
On 14/11/2019 00:02, Fredxx wrote:
On 13/11/2019 21:52:01, Steve Walker wrote:
On 13/11/2019 21:25, Fredxx wrote:
On 13/11/2019 19:52:56, Chris B wrote:
This summer I had a new gas boiler installation in an airing
cupboard near the centre of the first floor.Â* Flue goes into the
loft space and across to a gable end.Â* Having just been up into the
loft I see that the fitters have disturbed a lot of insulation
whilst installing the flue and not bothered to put most of it back
properly.

Are there any regulations about how close to gas flue pipes loft
insulation can be?

The flue pipe is plastic so presumably gets nothing more than warm.

The only rule regarding flues I'm aware of is they must be separated
from (combustible) timber by 75mm of air, or 25mm of incombustible
material. I wasn't aware of any requirements where the flue is
buried in insulation.

Interesting - I presume the distances from combustible materials were
defined for old-fashioned, very hot, metal flues. There would seem to
be no point in any separation at all with co-axial flues, where the
outer tube carries only ambient air; even less with co-axial flues on
condensing boilers, where even the inner, exhaust section is plastic!
Either there is something I haven't thought of or the regs are way
out of date for modern systems.

I'm going by experience in a timber framed house. This document is
useful:
Â*Â* https://www.igem.org.uk/_resources/a...ll/0/49955.pdf

I've not had a proper look, but a quick glance seems to suggest 25mm
separation and only 10mm for a concentric flue for a boiler.

SteveW

Thanks for the responses. Looks like I can just put it back as best I
can without being too fussy about clearances.

--
Chris B (News)