98
Aquarea air-to-water heat pumps - Planning and installation manual - 02/2022
Planning
5
Conversation
55
10,000
Normal
Road
80
100,000
Loud
Press air hammer
100
1,000,000
Very loud
The result of the non-linear perception of the sound pressure is that two equally loud sound
sources are not perceived doubly as loud as one sound source, but only as 3 dB louder than one
sound source. Doubling the sound intensity (volume) of a sound is linked to a sound pressure level
increase by 10 dB.
The measurable sound pressure level, which is converted into a rating level, in order to take
into account other factors such as tonal components of a sound, is the decisive condition for
maintaining the limit values. This must not exceed the valid immission guide values for immission
points outside buildings (example of Germany: Technical Instructions on Noise Abatement
(TA Lärm)).
Example of Germany: Immission guide values according to “TA Lärm”
Industrial Areas
By day and night
70 dB(A)
Commercial areas
By day
65 dB(A)
By night
50 dB(A)
Business zones
By day
60 dB(A)
By night
45 dB(A)
General residential zones
By day
55 dB(A)
By night
40 dB(A)
Purely residential areas
By day
50 dB(A)
By night
35 dB(A)
Spa areas, hospitals
By day
45 dB(A)
By night
35 dB(A)
The values relate to the measurable value at a distance of 0.5 m from the centre of the opened
window of the room affected and requiring protection. They are mean values and may be exceeded
by short sound peaks.
The measurable sound pressure level depends on the distance to the sound source and decreases
with increasing distance.
5.2.1.2 Sound power level for approximate calculation of the sound pressure level
The sound power level is a quantity for rating the sound source independently of the distance
and direction of the sound propagation. It is a mathematically determinable quantity, which is
determined for individual devices in laboratory measurements under defined conditions. Based on
the sound power level of a specific device, the sound pressure level can be roughly determined at
a certain distance and for corresponding sound propagation conditions for a given situation.
Sound propagates equally in all directions with the sound power of the sound source. The area,
through which the sound passes, increases as the distance to the sound source increases. This
results in a continuous reduction in the sound pressure level for the same sound power.
The sound pressure level is also affected by the following factors during the sound propagation:
●
Acoustical shadows cast by obstacles such as buildings, walls or land formations
● Reflection on reverberant surfaces such as walls, glass facades, buildings or
asphalted floors as well as stone flooring
● Absorption of the sound, for example by grass, bark mulch, leaves or freshly fallen
snow
● Wind can strengthen or reduce the sound pressure level (depending on the wind
direction)
