Detailed recommendations for the flue are detailed in BS6644 and IM/11. The following notes are
intended for your guidance.
The area of the flue serving the boiler must be not less than the area boiler flue outlet.
Nominal flue pipe diameters between the boiler and chimney should be in accordance with the fol-
lowing table:
REGENCY 4 MODULEK -152
300 mm
(12”)
REGENCY 4 MODULEK -169
300 mm
(12”)
REGENCY 4 MODULEK -186
300 mm
(12”)
REGENCY 4 MODULEK -203
300 mm
(12”)
REGENCY 4 MODULEK -220
300 mm
(12”)
REGENCY 4 MODULEK -237
350 mm
(14”)
REGENCY 4 MODULEK -255
350 mm
(14”)
REGENCY 4 MODULEK -272
350 mm
(14”)
Flue pipes and fittings should be constructed from aluminium, stainless steel or acid resistant vi-
treous enamel lined cast iron. Any double walled flue pipe, must be acceptable to British Gas.
Chimneys should be lined with non-porous acid resistant material in accordance with BS5854,
such as stainless steel flexible flue liner or similar British Gas approved material. The internal
diameter of the liner must not be less than the recommended flue pipe and the number of joints
should be kept to a minimum. Any joints between the flexible liner and the flue pipe from the boi-
ler should be effected by means of a purpose built adaptor plate. Existing flues should be tho-
roughly swept before use and any register plates, restrictor plates or dampers should be removed.
If the flue is not fitted with a terminal, then the flue outlet should be fitted with a wire mesh to pro-
tect against blockage. The terminal should not be sited adjacent to any opening window, air vent,
or other ventilation opening and should be situated at least 1 m above the roof surface. All should
be in accordance with BS6644.
FLUE SYSTEM
2.3
AIR SUPPLY
2.4
Detailed recommendations for air supply are given in BS6644. The following notes are
given as guidance.
AIR SUPPLY BY NATURAL VENTILATION
2.4.1
The purpose provided space housing the boiler(s) must have permanent air vents commu-
nicating directly with the outside air, at high level and at low level. Were communications
with the outside air is possible only by means of high level air vents, ducting down to
floor level for the lower vent(s) should be used. For an exposed boilerhouse, air vents
should be fitted, preferably on all four sides but at least on two sides. Air vents should
have negligible resistance and must not be sited in any position where they are likely to
be easily blocked or flooded or in any position adjacent to an extraction system which is
carrying inflammable vapour. Grilles or louvres should be so designed that high velocity
air streams do not occurr within the space housing the boiler(s).
The air supply requirements stated below are related to the maximum rated heat INPUT
of the boiler(s) and are equivalent to those specified in BS6644.
The total minimum free area requirements of the air vent are as follows:
Total input rating
Position of
Air Vent areas
of boiler installation
Air vent(s)
(Air direct from outside)
Up to 2 MW
High level
270 cm
2
plus 2.25 cm
2
per
(outlet)
kilowatt in excess of 60 kW
total rated input (gross)