Measurement Technology in Immission Control
For remote data transmission there is a modem, which continuously transmits all parameters to the office. Air quality measurements have also been integrated into our online monitoring system so that the local
Immission control is an essential element in the implementation of large projects. Be it noise, vibrations, air pollutants
pollutant concentration and meteorological data can be retrieved via the
or electromagnetic fields – all of these factors have to be taken into consideration in the design for the operation and
Internet.
construction phases; their effects should be kept at a minimum. A good and fully developed measurement technology plays a decisive role e.g. for determining the current situation, for reducing immissions during the construction phase or for verifying the compliance with authority approvals after start of operation.
tional measurement instruments, so-called HV samplers. The HV samplers, type Digitel DHA-80, are used to record the air pol-
There is a great variety of measuring instruments from simple hand-
Parts of the eastern section of the Wienerwald tunnel were driven by
held devices to large vehicles. In the past years iC has seized the chal-
blasting. Nuisance to neighbouring residents caused by vibrations and
of a daily average value. The sampler is equipped with a filter package
lenges and opportunities of measurement technology in the field of
secondary airborne noise was therefore to be expected in some areas.
including 14 individual filters. Particles sucked in from the ambient air
The monitoring system provides a graphic overview of the structure (Illustration 1), allows the selection of immission points and shows the
the training of our staff we have also focused on developments in the
measurement results (Illustration 2).
fields of long-distance data transmission and data storage.
Another advantage of the system is the structured storage of the
characteristics
For the monitoring of the air quality during the construction of the Koralm tunnel (2008 – 2013) we have only recently acquired two addi-
lutant particulate matter PM10 by means of gravimetric measurement.
addition to investing into the necessary measuring instruments and into
tics (vibration forecast, earthquake protection, status control) • Dynamic excitation of bridge structures for determining their dynamic • As seismic vibration source for geophysical investigations
In this case, however, long-distance data transmission is not possible.
immission control and today has a vast array of options in this field. In
• Dynamic excitation of buildings for determining dynamic characteris-
The concentration of particulate matter PM10 is recorded on the basis
are deposited on the filter and are analysed in the laboratory in a twoweek interval.
The vibration generator was used for the first time by iC consulenten in spring 2007 for vibration investigations by means of the VibroScan® method in the completed exploration galleries of Leibenfeld (Styria) and Mitterpichling (Carinthia). In Leibenfeld in Styria it was necessary to bring the vibration generator down to gallery level with the help of a crane, which was done through an approx. 60 metres deep access shaft (Illustration 8).
Acoustic camera The acoustic camera (also beamforming or microphone array) is a method for locating noise sources. Beamforming is an appropriate
VibroScan®
method if measurements close to the measurement object are impossi-
measured data in a central database. Contrary to conventional pro-
In early 2007 iC consulenten was able to acquire from the Austrian
ceedings which consist of the preparation of logs for each day in paper
Central Institute for Meteorology and Geodynamics (ZAMG) a vibra-
People living in the direct vicinity of large construction sites are often
form, this system allows to carry out additional evaluations at any time.
tion generator type Mertz 10 including the trademark rights for the
iC uses the beamforming method mainly for locating noise sources
heavily affected by construction noise and vibrations. Accompanying
Depending on the level of detail of the information fed into the system,
VibroScan® method. The VibroScan® generator, which was originally
in industrial plants for the identification of the noise sources with the
measurements allow to control the compliance with threshold limits and
more or less detailed evaluations may be prepared. Illustration 3 shows
developed for oil prospection, is used by iC as vibration source in the
highest emissions, which is a prerequisite for the targeted planning of
measures can be set either to keep immissions below thresholds or to
an example of such an evaluation.
scope of vibration control projects.
Monitoring of construction noise and vibrations
is important to react quickly to the measurement results. Efficient longdistance data transmission is thus a basic requirement for construction monitoring. A rather simple method is to position measuring instruments on
Monitoring of air quality The Air Pollution Protection Act (Immissionsschutzgesetz - Luft, IG-L)
or passing trains.
sound insulation measures to reduce operational noise emissions in the
As in railway superstructures this device stimulates vibrations of the
reduce them again in case thresholds were exceeded. For this purpose it
ble or can only be carried out with great difficulty, e.g. arriving airplanes
residential neighbourhood.
tunnel and the ground through surface load. Together the static and the dynamic surface load of the vibration generator reach a maximum N/cm2,
defines the threshold values of air pollutants to protect the health of
value of 6.2
human beings, animals and plants. Air pollutants for which such thresh-
sure on the rail bed of a full normal gauge railway (freight train). With
which corresponds to the simulated surface pres-
Functional principle of an acoustic camera In most cases the microphone is placed on a level surface. Basically, circular, cross-shaped, linear or quasi random arrays are used.
smaller construction sites, which send an SMS to the cell phones of
old values are defined include i.a. nitrogen dioxide NO2, particulate
a maximum force of 69 kN the hydraulic vibration generator system can
members of the construction team (this can be any person involved
matter PM10, benzole C6H6, sulphur dioxide SO2 and carbon monoxide
stimulate sinusoidal oscillations of 10-120 Hz over the entire working
in the construction process e.g. operators, site managers or authority
CO. Particularly the air pollutants nitrogen dioxide NO2 and particulate
frequency range.
experts) via GSM modem in case critical values or threshold values are
matter PM10 are substances for which regions, whole districts, cities or
The VibroScan® method offers not only a stepless frequency selection
array on the different measurement points on the measurement object.
Measuring principle The basic principle of such measurements is to focus the microphone
reached. The advantages of long-distance data transmission are evident:
municipalities are defined as polluted areas. Polluted areas are those
of the sinusoidal oscillations in the entire working frequency range, but
This is done through a time lag of the signals registered by the micro-
quick reaction, information around the clock, without the necessity to
areas in which the threshold values are exceeded. Nitrogen dioxide
also the possibility to define the frequency bands which are passed (so-
phones corresponding to the propagation time of the signal from the
have access to the adjacent buildings or to measuring points for reading
NO2 and particulate matter PM10 are substances which are relevant for
called sweeps). Thus resonances in vibration propagation can be reliably
measuring point to the individual microphones. The time corrected sig-
the data.
air quality during construction (emissions of engines of construction
recorded.
nals of all microphones are added up resulting in a time signal assigned
In the case of larger projects with several measuring points passive or active data download is an appropriate method. Passive download
machines and trucks as well as dust development through the handling of materials).
Illustration 7 shows a sweep of 12 s at a frequency of 10 Hz to 120 Hz. The lower part of the illustration shows a spectrogram of this sweep.
to the respective measurement point. The noise of sources on other positions is thus dampened down, as their signals are no longer completely
means that data are downloaded from the measuring instrument via the
Due to an increased demand for air quality measurements in the
As can be seen from the diagram, the sweep through the frequency
time corrected and partly interfere destructively. The noise radiated from
GSM connection by a measurement engineer, who interprets the data
scope of installation approvals, projects in polluted areas or for the moni-
range shows a constant increase. Resonances cause stimuli in the higher
the individual measurement point (focal point) is amplified. The quality
frequency range.
and prepares a measurement report. Active download means that the
toring of the air quality during the implementation of major infrastruc-
measuring instrument actively transmits the data to a central server at
ture projects iC consulenten has extended its scope of services to include
regular intervals (which may vary from 30 minutes to one day). The data
measurement technology for air pollution control.
a colour code and inserted into a conventional video image of the meas-
unsprung wheel mass/excitation mass (kg)
950 – 1600
1450
urement object. This allows to easily identify the positions of the main
measurement station is equipped with instruments for measuring the
maximum excitation force (kN)
30 – 100
69
noise sources. Different frequency charts are possible as well.
air pollutants nitrogen oxides NOx, nitrogen dioxide NO2, particulate
load area (m2)
4
2.9
matter PM10, carbon monoxide CO and ozone O3.
axle load / load on base plate (kN)
160 – 240
107
maximum average surface pressure (N/cm2)
4.8 - 8.5
6.7
frequency characteristics
broadband
monofrequent, up/down sweep
bandwidth (Hz)
30 – 80
10 – 120
noise levels) and made accessible via a web-based application. Daily,
time in the scope of a round robin test in Vienna in 2007. This air quality
weekly or monthly reports are automatically generated by the server.
are no special installations or programme licenses and data networks
The constant measurement of the air pollutant particulate matter
required. All you need is an Internet connection and a password to access
PM10 is carried out by applying the radiometric method for dust meas-
the measured data. Thus these monitoring data can be made accessible
urement, while nitrogen oxides NOx are measured with the help of a
to the site supervisor, construction company, designer, representatives of
chemiluminescence analyser.
the client and to the authorities.
The significance of the noise source is in most cases represented by VibroScan®
Our mobile air quality measurement station was used for the first
The opportunity to have access to the measurement data via the
Comparison of characteristics train
are stored, interpreted (converted into KB values or secondary airborne
Internet is of great significance for construction operation as there
of beamforming is further enhanced through the utilisation of elaborate digital filters.
The mobile unit furthermore contains instruments for meteorology
Comparison of characteristics of a train and a vibration generator
Prospects Increasing requirements on environmental protection in large projects will bring new challenges for the measurement experts of iC. We are already working on the development of systems that integrate vibration, noise and air quality measurements. Video data shall increasingly be included into monitoring in order to identify the reasons for the
This system was developed by iC and was used for the first time in
measurements. Via a 10 metres high pole the parameters wind direction
Austria at the Wienerwald tunnel construction site. Since then it has
and wind speed can be measured. Additional meteorological parameters
following fields of application:
accelerated through mobile devices (PDA, cell phones). The future prom-
been used successfully on various occasions.
are temperature, humidity and radiation balance.
• Simulation of train vibrations for vibration forecast
ises to be exciting and we will be a part of it.
08 THEMA communiCation, edition 10/2009
These characteristics make the VibroScan® generator suited for the
exceedance of threshold values. Access to data can be facilitated and
communiCation, edition 10/2009 THEMA 09