P&K 2714

Practical execution

Introduction

Geometries

The in P&K 2714 considered geometric objects are sources (point sources, line sources and area sources), obstacles (cuboids located on the ground), monitor points and creatively used elements (extra objects), which have no influence onto the calculation. All these elements can be entered via dialog forms or the drawing tool (menu View). For sources it is possible to link them to obstacles. This can be of advantage, when working with buildings which feature doors, windows etc. Instead of defining individual monitor points, one can create a raster in the form Definition of a receptor point net.

Sound spectra and levels

Sound parameter of an object (emission, attenuation) are to be entered at least as a-weighted value. For more precise evaluations, or when a distinctive frequency dependency exists, it is better to calculate using octave bands. When calculating with spectrums, a-weighted levels are calculated as well. In case of a-weighted levels are to be taken into account only, it is sufficient to enter a value whereever a sound levels is requested. For calculation in the octave band, a spectrum name has to be entered or selected from a spectrum defined in the spectrums list.

Spectrums list

Always when calculating with frequency distributions, or different situations are to be taken into account, levels are to be defined by references to the spectrums list. Spectrums can be entered manually, or by using the integrated spectrum generators, which calculates noise spectrums from technical data of various elements (e.g. steam throughput and temperature for a steam valve) or emission level (Lm,E) according to RLS-90 and Schall 03. In addition, access to spectrums catalogs for sound power absorbing materials and hall internal levels are supplied or user-definable. These forms can be opened via the right mouse button menu or via the button In all these forms an a-weighted level is calculated, because the guidelines taken into account offer not more. If a frequency distribution is known, it can be entered into the relative spectrum, from which an output spectrum with the same a-weighted level will be derived.

Sample

Concrete building with door (open during the day, closed during the night) on a cinder-court with road on the side and a concrete noise protection wall in between. (See project file tutorial.idp.)

Many of the following steps can be performed in a different order.

Spectrums

Enter Spectrums for the ground attenuation (reflection and dispersion), wall attenuation, the inside levels in the building, the attenuation of the door and the sound emission of the road into the form List of spectrums. The attenuation for the door is different for day and night. During the day there is no attenuation for the corresponding facade source.

For sound emission of the road, one can open the form Emission level according to RLS 90. This form can be opened via the right mouse button menu or via the button and it can be found under "Sound power levels". Emissions calculated in this form will be copied into the spectrums list by pressing OK button.

For the other spectrums, one can open the form Spectrums catalog and select one of the pre-defined items. Initially one has to open one of the supplied catalogs or any user defined one. The spectrums catalog can be opened via the right mouse button menu or via the button . A selected row will be carried over into the spectrums list by clicking the OK button.

Project Parameter

Enter global project data into the form Central model parameters.

Obstacles

Enter the obstacles (noise protection wall, building) into the form List of Obstacles. These objects can also be defined / placed in Graphical Tools for drawing objects. This form can be found under the menu View.

Sources

Enter the sources (door, street) into the form List of Facade sources and List of Traffic Sources. These objects can also be defined / placed in Graphical Tools for drawing objects. This form can be found under the menu View.

Monitor Point Raster

A monitor point raster can be defined in the form Definition of a receptor point net. The raster has to be generated from the menu. Individual monitor points can be placed in the form Graphical Tools for drawing objects.

Graphical Elements (optional)

Add a map and additional graphical elements. These elements can be placed in Graphical Tools for drawing objects

Prognosis

Verify input data and commit prognosis

Analysis (optional)

For analysis purpose the three-dimensional Illustration of the propagation paths is available. More detailed data can be determined for selected receptor under the menu Analysis.

Results

Under Prognosis / Area Map and Graphic, the area map and the illustration of the results are available. A report of the results can be generated under Prognosis / Report.

Day-Evening-Night level

Under Project Parameter we already have defined a third variant. Now we just need to check interpret as Day/Evening/Night and calculate Lden and will have the calculated value for L_den available. A new prognosis calculation is not required.