Overview

Noise can be examined in many ways. Its physical components can be defined, its medical impacts can be studied, its influence on safety in the workplace can be determined, and for describing aspects of the quality of life it can be assessed. When considering the quality of life, the less noise the better.

Less noise can be an appeal to people, "Hush, please be quiet," or an enforced noise limit. If a noise ordinance is in effect, active planning is needed to ensure that measures to limit noise are employed. With SoundPLAN you can create an acoustical model of the real world, simulate the existing situation and plan measures to decrease noise.

This article discusses the following SoundPLAN topics:

v   From Real World to Models

v  Archetypes of Noise Consulting Projects

v  Overview of the Components

v  SoundPLAN Commercial Modules

Using SoundPLAN on Consulting Projects

Before beginning detailed explanations concerning use of SoundPLAN in noise and air pollution studies, it is advisable to simply look at different types of studies, and explain the methods used for them.

SoundPLAN is a very flexible suite of programs capable of producing a variety of different types of results. Calculations can be performed for a single location with all of the intermediate steps documented or the results can be represented in graphical form using maps. Maps can visualize noise and air pollution concentrations with either the grid values or noise contour lines. All map types are based on calculations derived from specific locations.

Mathematics and physics are the same around the world, but planning and environmental law are defined locally. For SoundPLAN, this means that the physical aspects of noise are universal, but the tools chosen depend on local conditions and customs. The examples on the following pages are based on the German planning law and therefore may not completely apply in your environment. SoundPLAN's capabilities, however, are best represented using these consulting examples.

Differences in the planning process are reflected in the physical description of noise. In most parts of the world, noise is described in terms of the energy equivalent noise level, the Leq. However, in the UK, the descriptor for traffic noise is the L10 for the maximum hour and over an 18 hour averaging period and in yet other countries both the Lmax and the Leq are used for assessing the noise level.

From Noise Levels to Noise Rating

Most countries have rules concerning the maximum acceptable noise levels. These noise levels are determined according to the type of area and the time of assessment. During the planning process, the discussion can be simplified to whether or not the noise is acceptable, and if measures need to be taken to counterbalance it. If the noise is rated during different time slots, then the decision is more complicated. It would be advantageous to reduce the descriptor for the noise rating to a single value figure showing whether or not the noise is acceptable.

Because acoustic developments occur at different times and locations, answers to acoustic questions are also different. For the most strict noise limitation, for example, some countries use the Leq for night time, some use the loudest night time hour, and still others use definitions such as the SEL and NEF.

The Lmax can not usually be derived from calculations because of simultaneous noise events (a single train is an exception). Because of this, SoundPLAN is based on the physical descriptors of the Leq for different times.

SoundPLAN allows all descriptors to be processed. The first step is the calculation of the Leq for different time slots. The next step is the conversion to noise rating descriptors such as the SEL and NEF. SoundPLAN views noise calculations as follows:

 

        noise map = many different receivers ( Li,rated )

        Li,rated = Li + Corrections

        Li at one receiver = S Li from many sources ( Lw )

        Li = Lw - spreading - air absorption - screening - ground effect - ..

 

Technical aspects concerning SoundPLAN's definition of the Lw and how it calculates the Li are described in Chapter 6, which is attached as an Acrobat PDF File to be downloaded under the Support/ Downloads section of this website.

Objectives and Solutions

Noise and air pollution studies usually fall into two categories; studies to prevent problems from occurring and studies to find solutions for existing problems. The different categories often have different objectives, different noise limits, and different methods to achieve results.

In the planning stage, the exact location of buildings and noise sources is often not known and a concern is whether the planning should proceed or if anti- noise measures should be considered first. There are many uncertainties involved in this type of modeling. One must use approximations for numbers of vehicles, sound powers of machines and the final geometry. As project proposals are not yet built and may never be, calibrating measurements are not possible. Very often the objective in the planning process is reverse, calculating the allowable sound power that can be installed at an industrial location if the noise limits at noise sensitive receivers are not to exceed a certain level.

In the "fix it" mode, noise consultants use an existing situation to measure the noise, model the existing situation and calibrate it with the measured data. Then they can "play" with the options of source modification or screening until a solution is found.

In the following section, descriptions of typical consultation studies are described with their respective objectives and a brief note concerning how SoundPLAN can be used to find solutions. Again, the types of studies reflect the German planning law and might not completely correspond to the approaches taken in your country.

 

Road Projects

All traffic noise projects have many sources contributing to the model. For all source lines, a noise generation model needs to be created and calibrated. The numbers of vehicles for the status quo and the planned extension need to be defined as well as speeds and other factors influencing the generation of noise. For traffic noise in most countries, the emission is not defined via the sound power, but rather by the sound pressure in a reference distance. The reference distance varies from standard to standard. (We found 10m, 12.5m, 15m and 25m used in the standards).

A metro line is planned. The residential areas in the status quo are without noise problems. The rating used defines an acceptable noise limit during the day as 64 dB(A) and 54 dB(A) during the night in mixed areas and 59 / 49 dB(A) in residential areas. Included in the calculation is a 5 dB bonus defined in the German law for train noise. (Train noise is regarded as 5 dB less annoying than road noise of the same noise level). SoundPLAN uses the following procedures:

Calculating the Emission Level of both Tracks

For every train the speed, length and emission levels for each track are calculated in the train emission file of the Geo-Database. For roads the emission level can be calculated directly in the road alignment file.

Assessing the Study Scope

Next you need to define the area of interest. You can compare the noise contours in free field conditions to the noise limits of the areas. Everything inside the contours exceeding the limits must be evaluated. It is possible to give a rough estimate of the distance of the border contour line using the diagrams for free field propagation contained in most standards.

If the noise study is part of an environmental assessment study outside the city limits, the border noise contour must be determined in cooperation with the environmental planner.

Generating the Model

The next steps create a SoundPLAN model of the real world:

v The track file. Using the digitizer, enter the distance between the two tracks and for every coordinate, define the distance between the tracks and the elevations of the ground next to the railway line. (The ground elevation next to the train track is needed because it influences the ground absorption. The elevation of the track itself is not regarded for the ground absorption ).

v If you can build a noise control wall parallel to the track, copy the train track alignment into the screen file and move it sideways to the possible position of the screen (parallel move of lines). The wall height column can be filled with zero and the dimensions of the screen can be optimized with "Wall Design" later on.

v Enter the elevation lines defining the terrain and enter the buildings.

v Choose the characteristic noise sensitive receivers encompassing the entire area to be shielded.

Dimensioning a Noise Control Wall

The calculation run generated a file containing a matrix of the differences which the iterations of the noise screen produced. This file can be used to find the solution for reducing the noise levels for all receivers below the limits, while minimizing the cost. Different target noise levels can be assigned each of the receivers. The dimensioning can have as an objective either the smallest noise screen or the least cost. SoundPLAN calculates this by iteratively searching for the element of the screen yielding the biggest reduction of noise levels for all the receivers not yet properly shielded.

After the dimensioning is completed, the resulting wall can be fed back into the Geo-Database for other calculation runs.

Control Calculations and Result Documentation

As the wall optimization was determined for only one selected floor of the buildings and as the optimization is not exact in some cases (for details see Chapter 6, Wall Design), a control calculation must be made. Besides controlling optimization results, the documentation tables need the noise calculations performed once more to attain their results. They can only be generated during a calculation, not in the optimization process itself.

The documentation of results and differences occurs in Result Table Traffic, where the results from the calculations without noise control can be placed in one set of columns. The results of the calculations with noise control can be read into a different set of columns for the same receivers. This table has provisions for calculating the difference between the columns as well as differences to the noise limits. This table can be included in the appendix of the study paper.

Levels in Garden Areas

The noise quality in a garden area can be depicted best by plotting a noise contour map for 2 meters above the ground. Alternatively, single point receivers can be placed at patio locations. For single point receivers the noise contributions from all 360 degrees of the compass need to be taken into account.

Documenting the Geometric Model Data

If your SoundPLAN license contains the plotting elements, the geometry entered is best presented with a site plan including the heights of the noise control wall. Alternatively, the geometry can be documented with a printer plot which can be included in every calculation run.

Other Means of Controlling Noise

If the noise control wall proved to be high enough, the job is finished.

If the noise control wall reached the maximum height feasible and there were still receivers exceeding the noise limits, the excess needs to be documented for all buildings. A Facade Noise Map is suitable documentation when receivers along a facade exceed noise limits. This mode calculates receivers by selecting the first coordinate as a starting point and then following the building contour calculating receivers with a constant, user defined spacing.

With a Facade Noise Map you can document buildings that are not properly shielded. The maximum noise levels found in every facade can also be sent to a results file to be included in the result table traffic where the requirements of "passive" noise control can be determined. The "passive" noise control for this situation means that the noise on the outside of the building is exceeding the noise limits, so the building needs to provide the shielding. The necessary insertion losses of the windows are calculated from the parameters of the desired noise level inside, room size and Rw (Sound Transmission Index) of the existing wall.

Extension of Existing Roadways

It is planned to straighten the curve in a road. The traffic volume will not change, but the traffic speed will increase from 60 km/h to 100 km/h. Choosing a quieter type of pavement reduces the noise emission.

The noise pollution of the existing road needs to be considered. "Active" (designing noise screens) or "passive" measures can only be financed for buildings experiencing an increase of at least 2 dB(A) and exceeding the noise limits set in the ordinance to 49 dB(A) for the existing area type. The objective, then, is to find the area exceeding 49 dB(A) after the construction of the road that also causes a noise increase of more than 2 dB(A).

The data preparation process is very similar to the first example. The model data is entered in the Geo-Database for 3 different cases.

v Prognosis of the status quo to determine the noise levels in the existing situation for future use.

v Prognosis of the planned road with the same traffic volume as in case 1.

v Prognosis of the planned road with noise control measures.

The big difference between example 1 and 2 is that you must find the area with a noise increase exceeding 2 dB(A) and direct the noise control measures to this area. For documentation it may be helpful to calculate facade noise maps for the status quo case and the planned case, and then plot a difference map between the two defining a color change at the 2 dB(A) mark so it is easy to find buildings with a noise increase exceeding 2 dB(A).

Noise in the Planning Process

Planning a New Freeway

This is a classic case for a Facade Noise Map study. Noise values for each face of all the buildings must be calculated in order to consider noise protection measures. Tables with the noise levels are generated parallel to the maps. The noise levels for every story are entered in the table whereas the highest noise values per facade are documented in the plot map. SoundPLAN's "Noise Rating" evaluates the number of stories with excessive noise.

Noise in Regional Planning

When new residential areas are planned, it is good practice to consider the environmental impact the proposed area will incur, remembering that the noise limits applying to new areas are lower than the noise levels for existing areas.

SoundPLAN can be used for three parts of this type of planning; to show the feasibility of the proposed building site, to prepare the noise control measures and to provide data for the financial planning with the cost/benefit analysis.

Zoning also needs consideration. If the noise limits for the anticipated zoning can not be met without noise control walls or other measures, several options need to be simulated.

v How are different floors affected? Is the problem uniform or increasing with height?

v Is it possible to leave part of the area as originally zoned, and use another part of the area as a buffer or shield against noise and zone this area differently?

v Can the area be shielded with berms and walls in such a way that it is still commercially sensible to build at the proposed location?

The procedure for the study can be as such:

v  Digitize the noise sources (road, rail) and calculate the emission levels.

v  If the buildings positions and shapes are known, noise control can be completed for all floors.

v  If the buildings are not positioned, different orientations can be considered for maximum noise control; bedrooms can be oriented away from noise sources and garages can be used as shields.

After solving zoning questions and determining the exact locations of the buildings, noise control measures can be evaluated using wall design as a tool. Tables can be used to compare and calculate the differences between noise levels before and after noise control measures have been implemented.

If active noise control measures are not possible or are not sufficient, you must document the exceeded limits with tables and a facade noise map.

As the last step, cost sharing can be calculated for the active noise control measures. Only buildings exceeding the noise limits should be considered for payment. For this, a noise map of the final planning stage is calculated showing the facades exceeding the limit. Facades below the limit are deactivated. The other facades require a second calculation run with noise control measures in place. When both calculations are included in the same table, the differences the noise control measures created are visualized. The payment for the noise control measures can be divided by the number of receivers exceeding the limits and the amount of excess. Many different types of distribution are feasible, depending on the local attitude and legal aspects.

Railway Projects

Industry Noise Projects

Industrial Noise Control

Using the calculation methods included in the Industry Noise module, almost all noise problems of industry, community, and sports and leisure facilities can be evaluated.

Planning New Industrial Locations

A city may want to zone an area with good road access for an industrial project. In congested areas, noise limits in the adjacent residential areas need consideration. This means the noise levels in the planned area must be restricted so as to keep the noise levels in the residential areas below the limit.

The questions to be answered concern which parts of the proposed industrial site need which noise emission restrictions. To find the answers you can do the following:

v Define the noise sensitive receivers and examine the applicable noise limits.

v Digitize the industrial area. Partition the site into plots where uniform noise limits may be imposed. The noise levels need to be positioned at the height at which they will occur for the proposed usage. If the height is unknown, position the sources as an area source 6 meters above the terrain. Assume for all areas a uniform noise level of 65 db(A) / m². The frequency can be set to 500 Hz. For the propagation in the half sphere, a 3 dB addition is needed when using VDI 2714 or ISO 9613. The ground attenuation includes this effect in the Nordic standards.

v If the level is below the set limits, the task is completed, and if not, sections of the proposed industrial site require lower noise limits.

As the geometry has already been calculated, the propagation dependent calculations are also computed. If a constant to the various sources is considered, the levels can be obtained using the following formula:

Li = S for all Sources (Lw - mitigation - propagation)

Immission Assessment for a Building Permit

Let's assume a study similar to the last example proved that 60 dB(A) during the day and 45 dB(A) during the night is feasible as Lw / m². A vegetable wholesale market wants to build a storage facility at this location with loading time from 4:00 a.m. to 12:00 p.m. on workdays.

If all building lots keep within the noise limits assigned during pre-planning, it was proven that the cumulative resulting noise levels would be below the set limits.

The noise assessment will evaluate only the contributions the distribution center generates, and the applicable noise limits must be maintained for the entire border of the building plot.

As driving and loading the trucks generates most of the noise, the traffic to and from the distribution site is evaluated from the border.

The emissions from the trucks can be found either in literature or they can be measured. Measurements at comparable sites are often mandatory.

Normal noise levels are always calculated in accordance with physics. Noise assessment is more complicated and dependent on local procedures. The following example reflects concepts in the German VDI 2058, "Assessment of Noise in the Neighborhood."

The assessment level for this situation is very different from the previous equations of the sound pressure at the receiver which is as:

Li = Lw - propagation.

For the assessment level, different times have different penalties. The noise is calculated for every hour with a 6 dB(A) increase (special quiet time penalty) from 6:00 a.m. to 7:00 a.m. and from 7:00 p.m. to 10:00 p.m.. Later the noise levels for 6:00 a.m. to 10:00 p.m. and for the night are added energetically and averaged for an Leq,rated.

Noise ratings for different times of the day.

Procedures for the noise rating:

As the ordinance states the Lw / m² should be below 45 dB(A) during the night, the noise level at the closest residential building is calculated with this setting. This is the maximum noise the warehouse should create. The noise from the warehouse is not constant throughout the night, so each different source needs to be associated with a matrix of operations. The rating can be processed automatically if the control sequence "VDI2058" is included in the Run File.

To get the final approval for the noise concept of the warehouse, the noise screens need to be adjusted until the noise level in the residential area remains below the set limits. If this is not possible, limitations of night time operations will be imposed.

The best way to document this situation is to use facade noise maps for the residential buildings and a noise contour map for the area. If the key words "VDI2058" are set in the Run File, rated noise levels appear in the noise maps.

Noise in the Neighborhood

Sometimes noise from small facilities like hotels and discotheques affects the adjacent community.

As in the last example, the assessment uses the VDI 2058. The critical time period is the loudest hour of the night. The worst case scenario would be if all guests left the hotel during the same hour (after 22:00) and made a lot of noise in the parking lot. The noise can be assessed using the Parking Lot module included in the Road Noise Module.

 Carpentry Shop Noise

Noise from a carpentry shop located in a mixed business and residential area created a problem. The residents wrote a complaint that led to the study. The calculation was according to VDI 2714 / VDI 2720 and the assessment was according to VDI 2058.

Aside from outside noise sources, this study needed to assess the noise inside the carpentry shop, including noise emitted through the open door and the walls and roof of the building. The noise inside can be calculated with the "Indoor Factory Noise" module of SoundPLAN, or it can be measured. All calculations are completed in octaves.

Extending an Industrial Plant

The size of an already large industrial plant with many noise sources was to be further increased. As the orientation values for industry noise were not completely matching the requirement at the residential location, a noise rehabilitation program needed to be instituted.

All existing noise sources need to be measured and a model of the entire plant created. As the distances to the residential areas are big, all data should be measured in octaves. The model needs adjustment and fine tuning until the receivers, the measurements and the simulation agree.

After the status quo is processed, options to decrease noise throughout the plant can be simulated. If one measure alone is not sufficient, an array of options can be considered. (The EXPERT System in Version 4.0 will propose measures with the best price to performance ratio).

Using SoundPLAN for Consulting Jobs

After defining SoundPLAN's capabilities in different types of consulting projects, you need to know more about SoundPLAN's structure and work procedures. SoundPLAN is a modular package and the next section discusses all of the individual modules. However, only modules purchased in your license are included in your particular package, so features not included in your license will be hidden. Additions to the license can be obtained through your local SoundPLAN Distributor or from SoundPLAN LLC.

SoundPLAN Modules

The Geo-Database Separate Module Separate Module

Generates and manages all geometrical and descriptive data, result files and result spreadsheets. The RUN File assembles the calculation runs and prepares the data for plotting.

The Contour Generator Module connected to Grid calculation modules. Module connected to Grid calculation modules.

Calculates areas with the same noise levels and displays them in color steps. Colored areas can be plotted with a border of any color or thickness. Different algorithms are supported for the interpolation of contour lines.

Cartography Separate Module

Free generation of objects with free definition of attributes and fill/symbol types. Symbols and fills can be edited in a symbol editor.

Road Noise Separate Module

Calculates road traffic noise (and parking lots) in accordance to different user selectable standards.

Germany RLS 90/ DIN18005

Austria ÖAL 23 / Dienstanweisung / RVS 3.114

UK Calculation of Road Traffic Noise

Scandinavia Statens Planverk 48

Switzerland EMPA model

USA Federal Highway model

Railroad Noise Separate Module

Calculates railroad traffic noise in accordance to user selectable standards:

Germany Schall 03 / DIN 18005

Austria ÖAL 30

Scandinavia Nordic Rail Method

Industry Noise Separate Module Separate Module

Calculates frequency dependent industry noise in accordance to user selectable standards:

ISO 9613 Part 1 / Part 2

Germany VDI 2714 / 2720

Scandinavia General Prediction Method

Austria ÖAL 28

Oil Industry CONCAWE

Noise Ratings are supported for an array of standards. If your method is not included, call Braunstein + Berndt GmbH for assistance.

Expert System for Industry Noise Separate Module

Combines all results and source information for the industry noise into one comprehensive system. The optimization of noise control measures enables the user to find the most cost effective solution of noise control for small to very large facilities. Graphs indicate the effectiveness of the different measures.

Aircraft Noise Separate Module

Calculates aircraft noise in accordance to AZB [22] or DIN 45643 [23]. These standards are the proposed methods for Germany and Austria. Other countries may have deviations needing amendments.

Aircraft Noise Statistics Separate Module

Statistical presentation of the occurrence of the maximum level in table or graphical form. Different statistical and rating descriptors can be calculated.

Indoor Noise Calculations Separate Module

Noise calculation model for noise assessments in the workplace and as a preparation for calculations of environmental noise outside the workplace. The model is not suitable for building acoustics for designing concert halls, etc. SoundPLAN's implementation of the VDI 3760E [24] calculates noise maps in the building and calculates Sound Absorption Curves to assess the acoustic quality of the room.

Maps with Level Charts Included with any Graphics Module

Plotting attachment for level charts presenting before and after scenarios in one plot. Differences between two calculated receivers can be shown in detail.

Facade Noise Map Separate Module

Automatic generation of receivers along a facade to be calculated and plotted with color marks. The maximum level found at every facade can be cataloged in a result file.

Grid Noise Map Separate Module

A digital ground model evaluates the given elevation of buildings, roads, railroads and elevation lines and triangulates them. An equidistant grid is imposed over the resulting triangle mesh. The elevation is calculated from the triangles for every node inside a user definable calculation area. Then the noise levels are calculated for each grid point. After calculating all receivers, a grid noise map can be plotted and the contour generator can be used to plot the noise contour lines.

Vertical Grid Noise Map Separate Module

On a given line a user definable number of lines of receivers is calculates. In the graphics the Geo data are automatically intersected to coincide with the Vertical Grid Map. All normal Grid Map features apply.

The Grid Noise Map Evaluation Separate Module

Compares the grid noise calculation data with the noise limits set for an area. Noise exceeding the limits is plotted with reference to a user created scale. A Conflict Plan compares the excess noise level to the population densities.

Wall Design Separate Module

An auxiliary program to dimension and optimize noise control structures.

Window Dimensioning Separate Module

Calculates the necessary Rw from the input of room size, noise in front of the facade, Rw of the existing wall, and sizes of wall and window.

Source model and propagation calculation in accordance to the German MLUS for road traffic sources.

Source model and propagation calculation in accordance to the German TA-Luft for industrial sources.

Balance sheet for comparison of different source concepts for big models

Automatically calculates the pollutants at grid points and plots them in maps. The contour line generator is included in the package.

From the normal SoundPLAN geometry a system of cells is derived with information for where the wind can pass through the model. After the calculation of the wind field the pollutants trajectories are followed in the model. This model based on research of the University of Mainz in Germany is the official new Germany method according to VDI ???. The model can be used for traffic and industrial sources.

Graphical presentation of MISKAM airpollution calculations as a Grid Air pollution Map. The 3D wind pattern can be presented as a separate graphics type.

EnviroPLAN is used for environmental impact studies, where the risk can be calculated as a multiplication of impact and the attributes assigned to the object. Line and point objects are assigned riparian zones in accordance to their rating.

Three dimensional viewing and plotting of the model with hidden line and hidden surface algorithms. Colors are shaded in relation to the light source. The animation allows 3D graphics to be converted into a sequence of frames visualizing the model from the perspective of a driver, a pedestrian, or an airplane.

An open ASCII interface allows anybody to design their own input interface. Interfaces to other software products facilitate importing coordinate strings or complete models. Available interfaces include the file types from DFX and Shape Files from GIS.

 

SoundPLAN is a comprehensive software suit for environmental modeling needs. Environmental acoustics was the first corner stone, air pollution modeling was the second and environmental risk analysis is the third. Where ever possible, data from one area is reusable in another, ensuring the most cost effective work for any project.

SoundPLAN Structure

Showing the major components for the acoustical calculations is the best method of explaining the structure of SoundPLAN.

The program flowchart shows that the Geo-Database is the central part of SoundPLAN. You prepare the geometry of your model there and define traffic data and calculate the traffic emission levels. After the calculation core has loaded your model data and evaluated it, most of the results are fed back into the Geo-Database for additional formatting and printing.

All data structures involving geometry are managed with three dimensional coordinates. If external data sources are planned, they should also be planned as three dimensional objects or additional work will be necessary to add the third dimension. An alternative to importing data from other CAD packages is the acquisition of data from aerial photos with the heights and elevations calculated in the photogrammetry.

The RUN File of the Geo-Database is the command post where you assemble data and assign tasks. Calculations can be started for single point receivers, facade and grid noise maps. Data can be assembled into "transparencies" for plotting.

The graphics part of the program allows you to assemble different geometric, text and noise data for a drawing. The drawing can be rotated, zoomed and sized to your needs. You also have complete control over all colors, pen thickness and drawing formats. After a map with all components is prepared, it can be plotted directly or you can write a plot file. If you want to change some details of the plan later, you can call back all stored parameters of the map and make modifications.

The Structure of the Industry Noise

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Last modification: 22 October 2003