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Grid Evaluation

Variable Abbrev. Explanations
Level r0 current level at this grid point
Area of grid rectangle fl for a single grid point (in m2)
Limiting Value na for total noise
Limiting Value Industry naind -
Limiting Value Road nastr -
Limiting Value Railroad nasch -
Limiting Value Aircraft naflg -
(Land Use defined) naok grid point inside area of designated use, yes/no
Floor/Ground Ratio (GFZ) nagfz ratio floor area/ground area for each area of designated use
This figure (having no dimension) specifies what portion of the ground area of a site can be used for the total floor area of a building.
EXAMPLE: Assuming a site area of 500 m² with a ratio floor area/ground area limited to 1.0 means that the sum of all floor areas on all storeys can be up to 500 m² as well. This would allow, for instance, to construct a building with four floors with 125 m² area each (4 * 125 m² = 500 m²). With a ratio of 0.5 the maximum floor area would be 500 m² * 0.5 = 250 m².
Rental /m² /a namiete rental rate/m²/a for each area of designated use
Rental Abatement namind abatement of rental rate for each area of designated use
The abatement of rental rate for an increase of the noise level by 1 dB is specified in arbitrary monetary units (e.g. 1% percent abatement per 1 dB, as according to BUWAL-study BAFU301-1998)
Residents/km² naein population density of the area

For the expression all operators can be used as usual (see Chapter 5 - Operators & Functions).

Predefined expressions

Via the arrow key (>>) a list opens providing predefined expressions which will be inserted into input box "Expression" upon selection. The predefined expressions can be modified and saved to the list f expressions. The following evaluations are available:

  • LEG (noise load index):

    • pow(2,(r0-na)/10)*naein/1e6*fl or
    • \(naein * \frac{fl}{10^6}*2^{0.1*(r0-na)}\)

  • LB (noise load index):

    • max(r0-na,0)*naein/1e6*fl or
    • \(naein * \frac{fl}{10^6}*max(r0-na)\)

  • Monetary Assessment according to BUWAL-study BAFU301-1998:

    • aok*fl*nagfz*namiete*namindor
    • \(\frac{1}{100}*max[SPL-(Limit-5dB);0]\)

with

  • SPL: sound pressure level
  • Limit: limiting value

Examples

Expression Explanations
1 number of grid points
fl total grid area
naein*fl/1e6 number of inhabitants in all areas of designated use
iif(r0>=65,naein*fl/1e6,0) number of inhabitants subjected to levels of more or equal than 65 dB
iif(r0>=nastr,naein*fl/1e6,0) number of inhabitants subjected to a level above or equal to the limiting value for road noise
max(naein*fl/1e6*r0,0) as above, but applied to a map of conflicts
iif((r0<Lo)*(r0>Lu),fl,0) grid area (in m²) with a level above Lu and below Lo(Lo = upper level, Lu = lower level)