Q=8: Outdoor unit close to a house wall, next to a projecting
wall corner
Q=8
The following table shows the extent to which the sound pressure
level L
P
changes according to directivity Q and the distance from the
appliance in relation to the sound power level L
W
measured directly
at the appliance or at the air discharge.
The values listed in the table were calculated according to the follow-
ing formula:
Q
4 · π · r²
L = L
W
+ 10 · log
L
=
Sound level at the receiver
L
W
=
Sound power level at the sound source
Q
=
Directivity
r
=
Distance between receiver and sound source
The legal requirements concerning sound propagation apply under
the following idealised conditions:
■ The sound source is a point source of sound.
■ Installation and operating conditions for the heat pump correspond
to the conditions when determining the sound power.
■ At Q=2, sound is emitted in a free field, no surrounding reflective
objects/buildings.
■ At Q=4 and Q=8, full reflection on adjacent surfaces is assumed.
■ Unrelated noise from other surrounding sources is not taken into
account.
Directivity Q, calculated on
site
Distance from the sound source in m
1
2
4
5
6
8
10
12
15
Energy-equivalent duration of sound pressure level L
P
of the heat pump in relation to the sound
power level L
W
measured at the appliance/air duct in dB(A)
2
–8.0
–14.0
–20.0
–22.0
–23.5
–26.0
–28.0
–29.5
–31.5
4
–5.0
–11.0
–17.0
–19.0
–20.5
–23.0
–25.0
–26.5
–28.5
8
–2.0
–8.0
–14.0
–16.0
–17.5
–20.0
–22.0
–23.5
–25.5
Note
■ In practice, actual values may differ from those shown here due to
sound reflection or sound absorption as a result of local conditions.
Therefore, the situations described by Q=4 and Q=8, for example,
often give only an approximate picture of the actual conditions at
the emission site.
■ If the heat pump sound pressure level as calculated approximately
from the table is less than 3 dB(A) different from the permissible
standard value given by the TA Lärm, a precise sound immissions
prognosis must be produced (consult an acoustic engineer).
Standard values for assessing the sound pressure level to TA Lärm (measured outside the building)
Area/object
*14
Standard immissions value (sound pressure level) in
dB(A)
*15
During the day
At night
Area with a mix of commercial installations and residential units where nei-
ther commercial installations nor residential units dominate.
60
45
Areas with predominantly residential units.
55
40
Areas with only residential units.
50
35
Residential units that are structurally connected to the heat pump system
40
30
Note
■ Sound emission (TA-Lärm) regulations must be observed [in Ger-
many].
■ When siting the heat pump, always take into account the distances
to neighbouring property in accordance with local building regula-
tions.
*14
Determined according to outline planning restrictions; check with local authorities.
*15
Valid for the sum of all sounds that have an influence.
Design information
(cont.)
112
VIESMANN
VITOCAL
7
5831388
