# Norwegische Vorschrift, 2012/2017 (Englisch)

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The Norwegian guideline was in 2012 replaced by “Veileder til retningslinje for behandling av støy i arealplanlegging (T-1442/2012)”, later replaced by a 2021 version, which is described in document M-128 – 2020 from Miljødirektoratet.The revision does not change the the standard method used in WindPRO, but primarily provides a guideline for use of Nord2000.

The 2012 guideline is a combination of the Swedish guideline “Ljud från Vindkraftverk” from 2001 and the previous Norwegian guideline. It is also incompatible with the old guideline, which cannot simply be recalculated with the revised guideline.

**Calculation setup**

The calculation model is selected by choosing "Norwegian 2012" as Noise calculation model.

**Wind speed**

The Norwegian guideline describes a complex method of adjusting 10 m/s with actual roughness along the line of the older Swedish guideline, however advise as a more practical solution that calculations are done at the highest source noise level regardless of wind speed. As the typical wind profiles in Norway are governed not by roughness, but by topography only the highest source noise level option is available in windPRO.

In practice windPRO will consider the noise curve in the noise record selected for the turbine and pick the wind speed with the highest source noise level.

**Frequency**

Calculations within 1000 m of any turbine in the calculation can actually be calculated without octave data. However for wind farms larger than one turbine the 1000 limitation will almost certainly be exceeded and so octave band distributions are required. If the turbine noise record used does not hold octave data a generic distribution is fitted to the dBA value of the highest noise value.

**Wind direction**

Whereas the previous guideline advised an upwind reduction, the present guideline refuses this option. The meteorological coefficient should remain 0.

**Offshore wind farm**

In case of offshore wind farms this option is hatched. The methodology is the same as for the Swedish model and the calculation method is almost identical.

**Time domain**

The Norwegian codes operate with noise values as L_{den}, where den is an abbreviation of day-evening-night. It represents a weighted average of noise, where noise during evening and night is penalized. The parameters can be seen or modified by pressing the Edit period button as seen below.

The period definition of day, evening and night can be set here, as well as the penalty due for each period.

Because of the L_{den} calculation method different noise modes can be set for the turbines for day, evening and night and WindPRO will calculated the combined L_{den}. If all periods use the same noise mode L_{den} corresponds to Leq24 + 6,4dB.

#### Noise limits

Noise limits in Norway are governed by zoning. Dwellings receiving more than L_{den} = 40 dB(A) must be calculated. The noise limit of the dwelling depends on the zone in which they are situated.

The allowed noise impact is:

Yellow zone (Gul sone): L_{den} 45 dB(A)

Red zone (Rød sone): L_{den} 55 dB(A)

The relevant zone can be selected in the noise receptor.

#### Alternative methods

The Norwegian guideline allows for noise to be calculated using alternative methods such as Nord2000. The 2017/2018 revision of the guideline focuses on the Nord2000 calculation. In the final assessment of noise impact in Norway is is likely that Nord2000 is required. A summary of Norwegian Nord2000 requirements is given in the according NORD2000 manual page.

#### Curtailment optimization considerations

It is not possible to use the noise matrix with Lden calculations and hence it is not possible to use the Norwegian model in the curtailment optimizer.