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Building Evaluation

According to the requirements of RLS-90 RLS-1990 and using the map symbols defined in this guideline, there is a fairly simple way of demonstrating for a building close to a traffic route whether the predefined and maximum permissible rate levels on the basis of designated land use have been exceeded. It is also possible to ascertain which storeys this is true for and which values are to be expected at the most exposed position of the facade during the day and night.

Procedure

  • We activate - for better understanding and not because it is necessary - the option „No calculation of Building Noise Map“ in the menu Options|Building Noise Map (see Building Noise Map).
  • Insert the object „Building Evaluation“ with the corresponding icon from the toolbox. For that, click inside the building plan for that building for which an evaluation is supposed to be made.

Example

Path: Examples\Immissions\Industry.cna

  • After placing the first symbol we should adjust the size if necessary. All further inserted symbols then have the same size.

If several or even all buildings or only buildings with a certain condition of a project shall be evaluated we can use the command from the context menu Modify Object, action „Generate Building Evaluation“ to insert the Building Evaluation symbols all at once (see manual "Introduction to CadnaA").

In this case CadnaA automatically places these symbols in the selected buildings. The name of the building, entered in the identically named edit box in the edit dialog, will be automatically transferred into the corresponding input box of the building evaluation symbol.

Building Evaluation with Condition

In order to generate a building evaluation only for buildings e.g. with a certain height and/or base area a corresponding numerical condition can be defined.

Action „Generate Building Evaluation“ with condition

To insert an expression for a condition activate the pertinent check box and either enter an attribute (see CadnaA-manual „Attributes, Variables, and Keywords“) via keyboard or select them from the list which opens by clicking the button with the double-arrows.

With the above example would be generated symbols for all buildings which have a relative height higher than 3 m and a base area bigger than 50 m². In this case both conditions must be „true“.

Symbol Size

Adjust the symbol sizes via the table Building Evaluation (Tables menu|Other Objects) using the context menu command Change Column (see Changing Column Content), and also define the type of Land Use (if any). First insert just one symbol and specify all settings as required. CadnaA will keep the settings for all further building evaluation symbols when using the action „Generate Building Evaluation“.

Default situation: The building evaluation symbol is set for the upper left building. The calculation has not been launched yet

When a building is evaluated, levels computed by CadnaA for all storeys and in front of all facades are compared to the pertinent limit values or standard values. The latter can be defined in two ways.

  • Double-clicking on the building evaluation icon opens the corresponding dialog.
  • Activate the appropriate option for the standard values.

If the option „Determine from Designated Land Use“ is deactivated, you can select the type of area by clicking the card-index icon next to the „Land Use“ box, and the type of noise can be selected in the „Use Standard Values for“ list box.

Although this building evaluation was originally aimed at traffic noise, this flexible concept can also be applied to other types of noise like, e.g., industrial noise.

Building Evaluation of a building in a residential area (WA), with respect to road traffic noise

Designated Land Use icon

The second way is to click the Designated Land Use icon and assign a type of land use to an area by drawing a closed line around it. Then activate the option „Determine from Designated Land Use“. The standard values to be compared should then be known.

When all buildings have been provided with a building evaluation symbol, and the calculation is triggered by clicking the Pocket-Calculator icon on the toolbar, the progress bar window will first display the calculation for the specified receiver points and then the progress of the building evaluation.

In this building evaluation, calculations are performed and evaluated one after the other

  • for all buildings bearing this symbol,
  • for all storeys which result from the ratio of building height to storey height (storey heights may be edited under button „Options“ on the edit dialog Building Evaluation), and
  • for all outer facades.

Building Evaluation Symbol after calculation

Upon completion of the calculation, the top semicircle of the icon indicates the range of storeys where excess levels occur. If it remains blank, no excess levels occurred, or no area of designated land use has been assigned. The bottom quarters display the levels according to the selected „Averaging Method“ for the first and second evaluation parameter (see Evaluation Parameters Tab). By default, these are the daytime level Ld and the night-time level Ln.

Labeling of the buildings after calculation

Buttons

Geometry

coordinate X, Y (m)

Use different Calculation Point

In some cases it could make sense to place the building evaluation symbol outside the layout of the house. For that you can check the option „Use different Calculation Point“ on the dialog Geometry and place the symbol somewhere outside of the house without loosing the connection to this building. The original coordinates will be saved.

  • Insert the symbol within the building base.
  • Open the dialog Geometry and check the pertinent option.
  • Close all dialogs with OK and push the symbol outside the building.

The calculation point is displayed with a connecting line (auxiliary polygon).

Attribute: USE_PCALC

Activation via Change Attribute|string: „x“

When transforming the Building Evaluation Symbol (via dialog Modify Objects or via the context menu, action/command Transformation) the connecting line will be transformed automatically.

Directivity

A directivity can be assigned to the facade points generated via the "Building Evaluation" object. Sound rays incident from different angles at a facade point‘s location are weighted by the selected directivity and added energetically.

The selection of receiver directivity is made via the Directivity dialog (see Directivity at Industrial Sources, Directivity dialog, with the direction vector orientated perpendicular to the facade‘s surface). User-defined directivity is entered via the Directivity libraries (see User-defined Directivities).

Rotating the Building Evaluation Symbol & Facade Points

By default, the Building Evaluation symbols and the facade points are aligned 0 degrees to the y-axis. This setting can be edited - for example for output on rotated printouts - for the object type „Building Evaluation“ on the Options|Appearance dialog, tab „General“ (see General Tab).

Available options:

  • Angle (°) to the Y axis: reference to +y axis in the 2D plan view
  • Angle (°) to the North direction: Reference to the direction of the first North arrow symbol
  • Angle (°) to paper: reference to the paper sheet‘s edge orientation for rotated sections

Excluding Facades

In the edit dialog Building Evaluation if you click on the button „Option|Exclude Facade“ another dialog opens in which you can mark facades not to be taken into account for a calculation.

Dialog Exclude Facades

In order to exclude a facade, click once on the identifier in the upper list (e.g. F01) or double-click on the facade in the graphics below. Additionally shortcuts are available to step through the facades (F) and toggle the activation (SPACE).

Marked facades are excluded from the next calculation. On the lower graphic, the excluded facade is marked by a thick black line and the black dot (facade point) gets deleted. By clicking again on the identifier of a facade or double-clicking in the graphics this will again be included in the calculation.

The exclusion of non-relevant facades can save a reasonable amount of calculation time when evaluating a building noise map. At maximum 256 facades can be excluded.

Importing Building Evaluation Symbols

In case the buildings and the accompanying building evaluations are saved in separate files after a calculation run, no proper link between both objects is established when re-importing the building evaluations into the file with the buildings (via menu File|Import). This causes all building-related evaluations to fail (e.g. via the ObjectScan), since the corresponding data for the buildings does not exist (e.g. the building noise levels HB_LP1 to HB_LP4). In those situations, the link between the buildings and the building evaluations has to be reestablished. Use the command Link Buildings to Building Evaluations on the Extras menu to update the link.

Note

Please consider that when loading the building evaluations via the command PCSP|Load PCSP-Tiles (Calculation menu) the link is updated automatically (see PCSP - Program Controlled Segmented Processing). The above statements just hold when importing the calculated building evaluations via the menu File|Import.