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1.21 FLUE EXHAUST TO FLUE/CHIMNEY.
Flue exhaust does not necessarily have to be connected to a bran-
ched type traditional flue for type B appliances with natural drau-
ght (CCR).
The flue exhaust, for boiler clots installed in C configuration, can
be connected to a special LAS type multiple flue.
For B22 configurations, exhaust is only allowed into individual
chimney or directly into the external atmosphere via a relevant
terminal, unless otherwise provided by local regulations.
The multiple flues and the combined flues must also only be con-
nected to type C appliances of the same type (condensation), ha-
ving nominal heat inputs that do not differ by more than 30% less
with respect to the maximum that can be attached and powered by
the same fuel.
The thermo-fluid dynamic features (flue flow rate, % of carbon
dioxide, % humidity etc.) of the appliances attached to the same
multiple flues or combined flues, must not differ by more than 10%
with respect to the average boiler attached.
The multiple flues and the combined flues must also only be con-
nected to type C appliances of the same type (condensation), ha-
ving nominal heat inputs that do not differ by more than 30% less
with respect to the maximum that can be attached and powered by
the same fuel.
Chimney or flue sections for connection of the flue exhaust pipe
must comply with requisites of technical standards in force.
It is possible to replace a type C conventional device with one pro-
vided with condensation only, if the derogation conditions
established by the regulations in force have been verified.
1.22 FLUES, CHIMNEYS AND CHIMNEY CAPS.
The flues, chimneys and chimney caps for the evacuation of com-
bustion products must be in compliance with applicable stan-
dards.
Chimneys and roof-installed exhaust terminals must comply
with the outlet height and with the distance from technical volu-
mes set forth by the technical standards in force.
33
Positioning the wall flue exhaust terminals.
The wall flue exhaust terminals must:
- be installed on external perimeter walls of the building
(Fig. 33);
- be positioned according to the minimum distances specified in
current technical standards.
Combustion products exhaust of natural draught or fan
assisted appliances in open-top closed environments.
In spaces closed on all sides with open tops (ventilation pits, cour-
tyards etc.), direct combustion product exhaust is allowed for na-
tural draught or fan assisted gas appliances with a heat input range
from 4 to 35 kW, provided the conditions as per the current tech-
nical standards are respected.
