Technical building components in and around windows
Passive air vent
Unregulated / manually adjustable
Active air vent
Pressure- controlled
Moisture- controlled
Without heat recovery
Without s econdary heating /cooling
With heat recovery
With conditioning (two-pipe)
With conditioning (four-pipe)
C 3.2
C 3.3 Passive air vents
Window rebate
Glass rebate
Blind frame
Lintel / reveal Roller blind housing
Blind cover
Parapet
Volume flow [m3/h/m]
C 3.4
400
Self-regulating
Not self-regulating
350 300 250 200 150 100 50 0 0
Self-regulating damper
10
20
30
40
50
60
70
80 90 100 Air pressure [Pa] C 3.5
Particle size
Coarse dust 100 – 2,000 μm
Pollen 10 –100 μm
Smoke, soot
Tobacco smoke 0.01–1 μm
G1
‡
¥
¥
¥
G2
‡
¥
¥
¥
G3
‡
‡
¥
¥
G4
‡
‡
¥
¥
M5
‡
‡
‡
¥
M6
‡
‡
‡
¥
F7
‡
‡
‡
‡
F8
‡
‡
‡
‡
F9
‡
‡
‡
‡
‡ Effective
‡ Somewhat effective
¥ Ineffective
C 3.6
Purely passive opening elements regulate air flows mainly by mechanical means depending on the difference in pressure caused by the wind or exhaust air systems or on the humidity in the space. Many manufacturers produce air vents that can be integrated into windows in various ways. The least conspicuous solutions are rebate vents, which are installed between the win dow frame and sash frame. Air vents can be installed in the window’s glass rebate and frame, and solutions are also available for installing them in the window reveal or parapet, in roller shutter boxes or behind blind housings. It is easier to inconspicu ously integrate air vents into a facade by incorporating them into a window structure (Figs. C 3.3 and C 3.4) rather than position ing them in openings in walls, which is also often done. Most air vents have simple flaps that close in a strong wind. This prevents airflows that are too high, for example through leaky joints, and the resulting heat losses (Fig. C 3.5). Many air vents can be manually regulated and closed completely if no exchange of air is desired. Some models can be equipped with filters to keep out dust, pollen or other contaminants (Fig. C 3.6). Coarse filters in classes G2 – G4 as specified in DIN EN 779 are commonly used. Finer filters in classes M5 – F7 greatly reduce air throughput, so they are mainly used in air vents integrated into walls, because they have larger openings than vents built directly into windows. Air vents, like all openings in exterior walls, are acoustic weak points, but that should not mean that the wall fails to meet the sound insulation requirements against exterior noise as prescribed in the DIN 4109 series of stand ards. The sound reduction index R'W, res of the entire exterior facade, including windows and air vents, is decisive in this context. To improve sound insulation, some air vents are clad with mineral fibre or acoustic foam insulation. Since the insulation takes up space, improving sound insulation usually also involves increasing the size of the vent’s 199