A
B
D
60°
E
C
F
A
B
C
D
E
45°
F
10
3-FLUE
ROOF AT 60° ROOF AT 45°
SIZING
The negative pressure (draught) of a flue depends on its height. Check the negative pressure with the values indicated in the technical
characteristics. The minimum height of the flue is 3.5 metres.
The interior cross-section of the flue can be round (best), square or rectangular (the ratio between the internal sides must be ≤1.5) with
the sides joined with a minimum radius of 20 mm. The size of the section must be at least equal to that of the appliance outlet (smaller
diameters must be confirmed by an adequate system sizing calculation).
The cross-sections/lengths of the chimneys shown in the technical data tables are indications for correct installation. Any alternative
configurations must be correctly sized in accordance with the general method of calculation of UNI EN13384-1 or other proven efficiency
methods.
Below is a list of some flues available on the market:
AISI 316 steel chimney with
double chamber insulated with
ceramic fibre or equivalent
resistant up to 400°C.
Refractory chimney with
double insulated chamber and
external lightweight concrete
cladding with cellular material
such as clay.
Traditional square-section clay
chimney with insulating empty
inserts.
Avoid products with an internal
rectangular section where the
larger side is 1.5 times the
smaller side (e.g. 20x40 or
15x30).
EXCELLENT
GOOD
POOR
VERY POOR
FIGURE 6
FIGURE 5
A = MIN. 2.00 metres
B = DISTANCE > 1.30 metres
C = DISTANCE < 1.30 metres
D = 0.50 metres ABOVE HIGHEST POINT
E = 1.50 metres
F = REFLUX AREA
A = MIN. 2.60 metres
B = DISTANCE > 1.20 metres
C = DISTANCE < 1.20 metres
D = 0.50 metres ABOVE HIGHEST POINT
E = 2.10 metres
F = REFLUX AREA
