Detailed recommendations for fluing are given in the
current Building Regulations J/1/2/3.
The following notes are intended to give general
guidance.
The cross sectional area of the flue serving the appliance
must not be less than the area of the flue outlet of the
appliance and be at least 4.5m high.
The flue pipe to be used must not be less than 125mm
(5in) internal diameter. Flue pipes and fittings should be
constructed from one of the following materials:-
a)
Mild Steel with a wall thickness of 3mm minimum
b)
Stainless Steel to BS. 1499 Part 2
c)
Cast Iron to BS. 41
d)
Mild Steel, acid resistant vitreous enamel lined to
BS. 1344 Part 2.
Chimneys should be built of masonry or be assembled
from factory-made insulated components and be at least
4.5m high.
Masonry chimneys may be built of any masonry material,
with a lining, or if flue blocks, without a lining.
The chimney lining should be 150mm minimum diameter
and be formed of moisture and acid resistant liners to BS.
1181 with rebated or socketed joints uppermost.
Alternatively linings may be imperforate clay flue pipes as
described in BS. 65 or flue blocks to BS. 1289 and
installed to BS. 6461 Part 1.
An 150mm minimum diameter factory-made insulated
chimney, complying to BS.4543 may be fitted and
installed to BS. 7566 Parts 1 to 4.
Chimney Terminations
All chimneys should terminate above roof level in
accordance with current Building Regulations and
statutory requirements as outlined in BS. 6461: Part 1 and
BS. 7566: Parts 1 to 4.
NOTE
:
If the house is subject to down draughts or if
there are large buildings, hills, or tall trees close by
that may cause down draughts then an anti-down
draught cowl MUST be fitted. For standard chimneys
this could me an OH or Marcone pot. If the flue is
factory made prefabricated metal flue then a
proprietary cowl can be used for this purpose.
Chimney Cleaning
Ensure there are accessible airtight flue cleaning doors in
order to obtain cleaning access to the complete chimney.
Providing the appliance is operating correctly, an annual
chimney flue cleaning will suffice, but if in doubt, arrange
for a half yearly clean, preferably at the beginning/end of
the central heating season.
High Chimney Draughts
The appliance is fitted with an integral flue stabiliser, able
to control the draught in the flue pipe to about 6.0mm w.g.
A well sealed, tall exposed chimney on a hill, is an
instance where generated draughts could be in excess of
this figure.
Should this occur, an additional flue stabiliser must be
fitted either in the flue pipe or chimney, but in the same
room as the appliance.
Draughts in excess of 6.0mm w.g. must then be controlled
by adjusting this additional stabiliser down to this figure.
Detailed recommendations for air supply are given in the
current Building Regulations J/1/2/3.
The following notes are intended to give general
guidance:-
The minimum effective area of the permanent air vent in
the outside wall must be 82.5cm
2
(12.8in
2
).
Air Extract Fans
Building Regulations 1990 permit the installation of an air
extract fan in a kitchen containing an oil fired appliance.
The appliance must be able to operate effectively whether
or not the fan is running as follows:-
1. Ensure the fan duty is capable of coping with the
respective kitchen room volume. Avoid an oversize fan
duty performance.
2. Follow the directions recommended by the fan
manufacturer on the necessary air ingress needed for
the fan or overhead cooker hood, then add this
compensatory area to that recommended for the
appliances primary air needs. to form a permanent air
vent.
3. Ensure the wall location of the fan does not deprive the
appliance of primary air.
CHIMNEYS
AIR SUPPLY
Fig.2 - Flue Layouts
3
FLUE SYSTEM - see Fig.2
