151
Norsonic Nor140
Instruction Manual
151
Norsonic Nor140
Instruction Manual
Corner measurement for small rooms
For rooms with volumes less than 25 m
3
, the engineer-
ing Standard ISO 16283-2 requires additional meas-
urements in the corner of the receiving room. These
measurements are not possible with the Nor140 Build-
ing Acoustic mode.
However, by measuring the levels and reverbera-
tion time in mode 1 and mode 2 respectively, these
additional results may be included in the final calcula-
tion when transferred to the post-processing software
NorBuild or Nor850 BA-1.
Partly re-use of
previous measurements
When making several sound insulations tests where ei-
ther the source or receiving room is used in both tests,
it is convenient to re-use the averaged source level
and/or the averaged reverberation time from the first
measurement. By moving the cursor to either L
1
, L
2
, T
or L
b
before pressing the
DEL
key the corrected aver-
aged levels from the first measurement may be deleted
by confirming the delete process. Thereafter the new
measurements for the second insulation test are repeat-
ed for the receiving room levels or reverberation times.
Alternatively, each measurement at level or reverber-
ation may be stored individually for later re-use by the
RECALL feature. This is particularly useful for re-use of
reverberation time measurements for both airborne and
impact insulation using the same receiving room.
Facade insulation
General
The facade insulation may be measured using the
modes for airborne sound insulation − the outdoor
will then act as the source room. See ISO10052 and
ISO 140-5 as appropriate for further details regarding
requirements for the noise generating equipment and
the selection of microphone positions.
Use of traffic noise for facade measurement is not
covered in this description, as this requires simultane-
ous measurement in- and outdoor. However, this can
be achieved by using two Nor140 sound level meters.
Please contact your local Norsonic office for further in-
formation on such systems.
Terms and definitions
The following terms are used in the display:
L
1
sound pressure level 2 m in front of the facade
[dB]. The term is designated L
1;2m
in ISO 10052
and ISO 16283-3.
L
2
average sound pressure level in the receiving
room [dB]
T
reverberation time in the receiving room [s]
T
0
reference reverberation time equal to 0,5 [s]
k
reverberation index [dB]
D
nT
standardised facade level difference [dB]. The
term is designated D
2m,nT
in ISO 10052 and ISO
140-5.
D
n
normalised facade level difference [dB]. The
term is designated D
2m,n
in ISO 10052 and ISO
16283-3.
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