MCZ Forma Wood 75 Dx - mod.2012 - Manual (Page 12)

A
B
D
60°
E
C
F
A
B
C
D
E
45°
F
10
4-FLUE
ROOF AT 60° ROOF AT 45°
DIMENSIONING
The drop in pressure (draft) of a flue depends on its height. Check the drop in pressure with the values indicated in the technical
characteristics. The minimum height of the chimney is 3.5 meters.
The interior cross-section of the flue can be circular (best variation), square or rectangular (the ratio between the interior sides must be
≤1.5) with the sides joined with a minimum radius of 20 mm. The size of the section must be minimum equal to that of the unit outlet
(smaller diameters must be confirmed by an adequate system size 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 dimensioned 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:
Steel chimney AISI 316 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
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 ZONE
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 ZONE
FIGURE 5 FIGURE 6