©
EUROHEAT
DISTRIBUTORS (H.B.S) LTD. March 2006
Technical Guide IN1087 Edition C
20
Protecting buildings from hot
flues
Flue within:
Protection measures
Connecting
flue pipe
Flues should be at least 25mm
from any combustible material
(measured fromt he outer surface
of the flue wall, or the inner
wall in the case of multi-walled
products). Where passing through
a combustible wall, floor or roof
(other than a compartment wall
floor or roof) this separation
can be achieved by a non-
combustible sleeve enclosing
the flue pipe or chimney with a
25mm airspace to the relevant
flue wall. (The airspace could be
wholly or partially filled with non-
combustible insulating material).
Factory-made
chimney complying
with BS715:1993
Factory-made chimney complying
with
BS 4543-1:1990 (1996),*
BS 4543-2:1990 (1996),
and
BS 4543-3:1990 (1996)
Install in accordance with
Document J paragraph 1.45.
Masonry chimney
Provide at least 25mm of
masonry between flues and any
combustible material.
Flue block chimney
Provide flue block walls at least
25mm thick
* BS4543-1:1990 (1996) withdrawn April 2000; partially superseded by BS EN 1859:2000
Location and shielding of flues
Combustible materials in the building fabric should be protected from the heat dissipation from flue so that
they are not at risk of catching fire. A way of meeting the requirement would be to follow the guidance in the
enclosed table.
Where a flue pipe or chimney penetrates a fire compartment wall or floor, it must not breach the fire separation
requirements of Approved Document B.
Connecting flue pipes and factory-made chimneys should also be guarded if they could be at risk of damage
or if they present a burn hazard to people that is not immediately apparent.
Relining of flues in chimneys
Lining or relining flues may be building work or in any case, such work should be carried out so that the
objectives of requirements J2 to J4 are met ( Document J paragraphs 1.34 and 1.35). Existing flues being re-
used should be checked as described in Document J paragraph 1.36. For flue liners servicing gas appliances,
ways of meeting the requirements include the use of
a)
Liners as described in Document J paragraph 1.27;
b)
Liners as described in Document J paragraph 2.20;
c)
Flexible stainless steel liners independently certified as complying with BS 715:1993;
d)
Other systems which have been
independently certified as suitable for the
purpose.
Flexible metal flue liners should be installed in
one complete length without joints within the
chimney. Other than for sealing at the top and
the bottom, the space between the chimney
and the liner should be left empty unless this
is contrary to the manufacturer’s instructions.
Double skin flexible flue liners should be installed
in accordance with manufacturer’s installation
instructions. BS 715 liners should be installed
in accordance with BS
5440-1:2000.
