68
|
Fitting
UNIMAT
6 720 807 794 (2013/04)
Sizing ventilation and extract air apertures
• Size ventilation and extract air apertures to obtain a
pressure of
±
0 mbar in the boiler installation room.
• If the combustion air is routed via air inlet channels to
the burner, ensure an optimised flow path and
adequate sizing with regard to the pressure loss.
• The side ratio of the aperture must not be more than
1:2.
• Extract air cross-sections correspond to 60 % of the
ventilation air cross-sections.
The calculation formulae below are a
non-binding
recommendation.
It is essential that the system installer
seeks the agreement of the responsible approval or
building regulations body. Take into account additional
consumers of ventilation air (e.g. compressors) when
sizing.
For outputs ...
... the following calculation
applies for the free
ventilation air cross-
section
1)
1) A = free cross-section (net) in cm
2
, Q = output in kW
≤
2000 kW
A = 300 + [(Q – 50) × 2.5]
> 2000,
≤
20000 kW
A = 5175 + [(Q –
2000) × 1.75]
> 20000 kW
A = 36675 + [(Q –
2000) × 0.88]
Table 30 Calculating free ventilation air cross-sections