Roeterseiland Campus noise measurements (Sarphatistraat)
As part of the construction projects on Roeterseiland, last year the UvA placed noise meters to
measure the level of noise (at the rear of the residential block in Sarphatistraat 133-141) caused by
the construction work.
Following consultations with BAM, Amsterdam's Centre District and the UvA, the maximum level of
noise that may be caused by the construction work has been set at 80 d(B)a. The readings of the
noise meters allow residents, the UvA and BAM to verify whether the maximum noise levels are
being exceeded.
Each year, the UvA publishes the average noise levels produced by the construction work. These are
daytime values, since only the figures for between 7 a.m. and 7 p.m. are factored into the averages.
The enclosed report contains the figures for 2012 and 2013 as well as a description of how the UvA
calculates these figures.
Since 2013 noise meters have also been installed in Roetersstraat, on the roof of the Kriterion. The
figures registered by these microphones will be added later to the report.
VOLUME MEASUREMENTS 2013: How does the UvA calculate the annual average?
In 2012, three microphones were placed behind the houses on Sarphatistraat in order to measure
the volume of the noise created by the construction work on the Roeterseiland campus.
•
•
•
Mic.1: approx. 7.5 m from the ground - 4th storey
Mic.2: approx. 7.5 m from the ground - 4th storey
Mic.3: approx. 7.5 m from the ground - 4th storey
The results of the measurements were available for residents to view until 1 January 2014 at
www.geluidsbeheer.nl. On that date, management of the website was transferred to
http://my.dbeez.nl/beelen. A message to report this was sent via the neighbourhood news
(buurtbericht) on 16 December 2013.
The University of Amsterdam (UvA) uses all measurements taken on working days to calculate an
annual average once per year.
See below for a short description of how this calculation is made.
The Lden ( Level day-evening-night) is a unit used to express the level of sound generated by the noise
in the area.
In order to determine Lden, each 24-hour period is divided into three sections:
•
•
•
daytime 7.00 am - 7.00 pm
evening 7.00 pm - 11.00 pm
night-time 11.00 pm - 7.00 am
Firstly, the equivalent sound level is determined for each time period across the entire year,
expressed in dB(A).
Penalties of 5 and 10 dB(A) are added to the evening and night-time values respectively, as certain
volumes in the evening and during the night are perceived as more intrusive due to the reduction in
background noise from the environment compared to the daytime. It is also important to set more
stringent requirements for night-time readings due to the potential for disturbing sleep. There is no
scientific basis for the exact value of the penalties, however, these are the values that are commonly
used. The Lden then emerges as the logarithmic average of the daytime, evening and night-time
values, using an 'energetic' average calculation. This means that the values are also weighted
according to the duration of each time period. The values presented in the calculations on
www.geluidsbeheer.nl and http://my.dbeez.nl/beelen already include the above-mentioned
penalties.
For the Roeterseiland campus, this means that the following annual averages were calculated by
adding together all average daytime values (i.e. not including weekends, evenings or night-time) for
each microphone:
Microphone
1
2
3
Annual average 59.8 58.6 59.3
for 2013
Energetic annual 59.3
average for
2013 across
three
microphones*
Annual average 66.1 67.9 66.0
2012
Energetic
66.8
annual average
for
2012 across
three
microphones*
*This is then converted into an 'energetic' annual average using a set formula**
N.B.: Microphone no. 3 was removed on 1 October 2013. Calculations based solely on the readings
from microphones 1 and 2 result in an energetic annual average of 59.2.
As a formula, the energetic average is defined as follows:
L = 10·
10
log
10
L1 /10
+ 10
L2 /10
+ 10
n
L3 /10
+ 10
L4 /10
LAeq = 10*log[1/(t2-t1) * Integration of (P2A/P20) between interval [t1 t2] )
15 January 2014
+ ....