DOWN DRAUGHTS
However well designed, constructed and
positioned, the satisfactory performance of
the flue can be adversely affected by down
draught caused by nearby hills, adjacent tall
buildings or trees. These can deflect wind
to blow directly down the flue to create a
zone of high pressure over the terminal.
(See Fig.11).
A suitable anti-down draught terminal or
cowl will usually effectively combat direct
down draught but no cowl is likely to pre-
vent down draught due to a high pressure
zone.
Ensure that any cowl used will not restrict
the flue exit, or cause excessive back pres-
sure.
Fig.10
FACTORY-MADE INSULATED CHIMNEYS
Factory-made insulated chimneys should be con-
structed and tested to meet the relevant standards
and recommendations given in:
* B.S. 7566 – Installation of factory-made chimneys
conforming to B.S. 4543 for domestic appliances.
Part 1: Method of specifying installations design
information.
Part 2: Specification for installation design.
Part 3: Specification for site installation.
Part 4: Recommendation for installation design
and installation.
SUITABLE MATERIALS
*
Mineral Fibre cement pipes conforming to
B.S 7435.
Fig.11
9
IMPORTANT: THIS APPLIANCE SHOULD NOT
BE CONNECTED TO A CHIMNEY THAT IS
PRONE TO DOWN DRAUGHTING.
