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Building Evaluation

For the calculation of facade levels the building evaluation symbol in the CadnaA-toolbox is used.

The building evaluation symbol:

To calculate facade levels, proceed as follows:

Note

As an alternative to the keyboard enter the objects using the mouse in order to speed up the input procedure. In this case, consider the principles described in chapter Inserting Objects using the Mouse.

  • Add a point source at (x,y)=(100,100) and a building with the following corner coordinates:(x1,y1) = (140,90),(x2,y2) = (160,90),(x3,y3) = (160,110),(x4,y4) = (140,110).Enter a building height of 10 m on the dialog Geometry.
  • Select the building evaluation symbol from the toolbox and click within the borders of the building. The screen now looks as follows:

  • Double-click on the border of the building evaluation symbol. Click in the dialog on the button "Options" to display all options.

Select Type of Land Use

In order to address a limiting value areas of land use can be assigned for which corresponding limiting values have been defined. Alternatively, a type of area can be set after deactivation of the option „Determine from Areas of Land Use“. In CadnaA, the pre-defined types of land use are listed on the menu Options|Land Use. For example, for the land use "WR reines Wohngebiet" (in English: pure residential area) the following limiting values are defined depending on the noise type:

  • Select the object „Area of Designated Use" (symbol: ) from the toolbox and draw a polygon around the building.

Building with building evaluation symbol and Area of Designated Use

  • Double-click on the border of the area of designated land use and select "WR" from the list of land uses. Upon closing of the dialog the area is displayed according to the settings specified on the dialog Land Use (Options menu).

Define Height of Storeys

Furthermore, on the dialog Building Evaluation Symbol it is defined how the facade points are distributed across the building’s height. To this end, the height of ground floor above ground („Height Rcvr EG above Ground“) and the further heights of storeys can be defined. A predefined height of ground floor above ground of 2.5 m and a height of storey of 2.8 m results in:

  • the first floor reaching from 0 to 2.5 m height, and

  • the 1st floor reaching from 2.5 to 5.3 m etc.

The input box "Rounding up with last digit" enables to fix a rounding rule for the building noise levels indicated. For example, the default setting of 0.1 dB causes a level of 59.1 dB(A) to be rounded up to 60 dB(A).

Furthermore, via the button „Exclude Facades" facade parts not to be considered in calculation can be deactivated.

  • Start the calculation by a click on the pocket calculator symbol on the symbol bar.

Display of Results

After the calculation the range of stories in which exceedances (facade level above limiting value) is shown on the upper semicircle of the building evaluation symbol. If this semicircle remains empty, no exceedance occurred or an area of land use has not been assigned. The lower quadrants report the maximum levels for the day- and nighttime (i.e. for the first two performance parameters defined).

Building evaluation symbol with exceedances for storeys II and III(level for perf. parameter 1: 62 dB(A), for parameter 2: 40 dB(A))

Table Building Evaluation

The results of the building evaluation are displayed as well on the table Building Evaluation (menu Tables|Other Objects).

Object table „Building Evaluation“

Changing the Symbols Size

On this table, the size of the building evaluation symbol can be changed.

  • Click with the right mouse button in column „Coordinates, ∅ (m)“.
  • Select from the context menu the command „Change Column“.
  • On the dialog select „Arithmetic“, enter a new value of 4 m and close the dialog by OK.

Now, the building evaluation symbol is displayed with half of his former diameter.

Note

Of course, you can also overwrite the value shown on the object table of 8 m by typing "4". The procedure first-mentioned, however, provides a more comfortable approach with a variety of building evaluation symbols.