3
Twin Pipe Flue Systems
3
FLUE OPTIONS
3.1
HORIZONTAL FLUE OPTIONS - Lmax = 10 m (except Alpha 280E where Lmax = 6 m)
L = Equivalent length of flue or air duct (a 90° bend is equivalent to 0.50 m of flue length and a 45° bend is equivalent to 0.25 m
of flue length).
A = Total length of flue/air ducting required.
Fig. 1
Where D = 50 mm for each connection in straight ducting
Lmax = 10 m (except for Alpha 280E - Lmax = 6 m)
A = (2 x B) + C1 + C2 + D + 220 mm
Alpha 500E A = (2 x B) + D + 570 mm
B
Alpha 240/280 Range A = (2 x B) + D + 510 mm
B
B
L
C2
C1
REAR FLUE
SIDE FLUE
Fig. 2
B2
L
L
C1
C2
B1
Note: Ensure
there is an adequate
and permanent
air supply.
(Refer to BS 5440:1)
A = (B1 + C1) + (B2 + C2) + D + 60 mm
Where D = 50 mm for each connection in straight ducting
Lmax = 10 m (except for Alpha 280E - Lmax = 6 m)
