- Installation and maintenance are performed according
to the manufacturer’s instructions and the provisions of
current regulations.
- e max. possible length of the Ø 60 rigid ducting verti-
cal section is 22 m is length is obtained considering
the complete Ø 80 intake terminal, 1m of Ø 80 pipe in
exhaust, two 90° Ø 80 bends at boiler outlet.
- e max. possible length of the Ø 80 flexible ducting
vertical section is equal to 30 m. is length is obtained
considering the complete Ø 80 intake terminal, 1m of
Ø 80 pipe in exhaust, two 90° Ø 80 bends at boiler outlet
for connecting to the ducting system and two direction
changes of the flexible tube inside the flue/technical
hole.
1.7 Fume exhaust to flue/chimney.
e fume exhaust does not have to be connected to a conventional
type branched flue.
e fume exhaust can be connected to a
special LAS type multiple flue. Multiple flues and combined
flues must also only be connected to type C appliances
and of the same category (condensing), having rated heat
outputs not differing by less than 30% with respect to the
max. connectable and fed by the same type of fuel. e
thermofluidodynamic characteristics (flowrate in mass
of fumes, % of CO
2
, % humidity, etc.) of the appliances
connected to the same multiple or combined flues must
not differ by more than 10% with respect to the average
boiler connected. Multiple and combine flues must be
specially designed according to the calculation method and
requirements of the standards, by professionally qualified
technical personnel. Chimney or flue sections for connection
of the exhaust pipe must comply with requirements of the
standards.
1.8 Chimneys/flues.
General details.
A chimney/flue used to exhaust fumes
must:
-
in case of wet operation, be made of materials suitable for
discharging the condensate in compliance with the provisions
of current standards and regulations
;
-
be fumetight, waterproof and insulated
;
- be made from fireproof materials ensuring lasting resistance
to normal mechanical stress, heat and the action of fumes
and their possible condensate;
- have a vertical path without any constrictions;
- be adequately separated, by means of a suitable air space
or insulation, from zones with combustible and/or easily
flammable materials;
- be suitably designed to prevent the possible freezing of
condensate inside the fume system and condensate dis-
charge system (trap, passivator tank);
- comply with the current relevant national and local regu-
lations, for discharge of the condensate produced by the
fume exhaust system;
-
have a solid materials and possible condensate collection
unit below the opening of the first flue at a height of at least
500mm
, fitted with an airtight metal door;
- have have a round, square or rectangular internal section
(in the latter two cases, with rounded angles and radius of
not less than 20 mm). Hydraulically equivalent sections
are also allowed;
- have a chimney-top in compliance with the specifications
given below;
- be without mechanical extraction devices installed at the
top of the duct;
- in flues routed inside or against inhabited buildings, there
must be no risk of pressure surges.
Chimney-tops.
A chimney-top is the device generally in-
stalled on top of single or multiple flues. is device facilitates
the dispersion of fumes also in adverse weather conditions
and prevents depositing of foreign matter. It must:
- have a useful outlet section not less than double that of
the flue/chimney on which it is installed;
- be suitably designed to prevent the entry of rain or snow
in the flue/chimney;
- be shaped in such as way that prevents the formation of
frost and ice at the free outlet sections;
- be designed to ensure constant exhaust of combustion
products with any wind direction or angle.
e outlet height, corresponding to the height of the top
of the flue/chimney, regardless of any chimney-tops, must
be outside the “backflow zone”, to avoid the risk of coun-
terpressures that prevent the free release of fumes into the
atmosphere. erefore always respect the minimum heights
given in the figures for standards, according to the pitch.
Positioning of draught terminals.
Draught terminals must:
- be installed on external outer walls of the building;
- be positioned according to the minimum distances speci-
fied in current technical standards.
Fume exhaust of forced draught appliances in closed
open-top environments.
In spaces closed on all sides
with open tops (ventilation pits, courtyards etc.), direct
fume exhaust is allowed for natural or forced draught gas
appliances with a heating power range from 4 to 35 kW,
provided the conditions as per the current technical standards
are respected.
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