Installation manual
162
6.4.2
Air exchanges in the building
The calculated total number of air exchanges in all rooms should
be between 0.4 and 1 per hour.
Table 6.2: Fresh air volume flow according to DIN 1946, Part 6 and DIN 18017
“Lüftung von Bädern und Toiletten” [English: “Ventilation of
Bathrooms and Toilets”]
6.4.2 Installation recommendations for domestic ventilation units and the positioning
of the fresh air and exhaust air valves
The installation of domestic ventilation units and the routing of
the air distribution system should be carried out within the
thermal envelope of the building to minimize heat losses. Air
ducting must be insulated whenever the ducts are routed through
unheated or partly heated areas.
In the case of domestic ventilation units with integrated domestic
hot water preparation, the device is normally installed in the
cellar or laundry room with the aim of keeping the pipe runs as
short as possible.
Air volume flows should be selected so that the greatest possible
air volume flows from rooms with minimum air contamination
(fresh air rooms) to rooms with higher air contamination (exhaust
air rooms). The air overflow areas should be provided with the
necessary air overflow vents. These can be air gaps under the
doors (gap height approx. 0.75 cm) or a grill fitted in a wall or
door.
Air circuit
The flow velocities in the pipe system should not be greater than
3 m/s in order to keep noise generation and pressure drops to a
minimum. Fresh air valves and exhaust air valves should admit
a max. of 30-50 m
3
/h. Several valves should be installed to
accommodate larger air volume flows.
Fresh air (inblown air)
Doors and ceilings are preferred locations for fresh air valves
because these areas are not obstructed by either furniture or
curtains. Attention should be paid to a sufficient and even
circulation in the fresh air area when designing the layout. In the
case of decentralized systems, the fresh air vents should be
positioned in the upper external wall (e.g. close to the ceiling in
the vicinity of a window).
Exhaust air
The position of the exhaust air valves is of less importance for
domestic ventilation than is the position of the fresh air valves. An
appropriate position is in the ceiling or in the wall near the source
of the air to be discharged.
Fig. 6.8: Detail of a ventilation plan with a central fresh air and exhaust air system
Living space
m
Planned
occupancy
Fresh air flow
m/h
Up to 50 Up to 2 persons 60
50 to 80 Up to 4 persons 120
Over 80 Up to 6 persons 180
Air volumes Pipe diameter
Up to a max. 80 m
3
/h
Folded spiral-seam DN 100
Up to a max. 130 m
3
/h
Folded spiral-seam DN 125
Up to a max. 160 m
3
/h
Folded spiral-seam DN 140
Up to a max. 220 m
3
/h
Folded spiral-seam DN 160
Up to a max. 340 m
3
/h
Folded spiral-seam DN 200
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