TA Laerm for Wind Turbines

The Sixth General Administrative Regulation to the BImSchG (TA Laerm — Technical Instructions on Noise) is the binding assessment standard for wind turbine noise in Germany. It regulates permissible noise levels at residential buildings and provides the methodology for prognosis and evaluation.

Immission Thresholds (Section 6.1 TA Laerm)

TA Laerm thresholds by area type — day vs. night (WTG-relevant areas highlighted)

For wind turbines, the night-time threshold at the nearest WA area (40 dB(A)) or MI/MK/MD area (45 dB(A)) is decisive in practice — wind and therefore noise are often strongest at night, and WTGs operate 24/7.

How Is Noise Measured / Predicted?

1. Sound power level L_WA of the individual turbine from manufacturer measurement (FGW TR 1, IEC 61400-11) — the unrounded source value
2. Propagation calculation per DIN ISO 9613-2 (point source model, octave bands)
3. Level addition for multiple WTGs + pre-existing noise from other sources at the immission point
4. Worst-case additions: +2σ on manufacturer L_WA, unfavorable weather/wind direction assumed
5. Comparison with threshold for the area type at the immission point

When the Threshold Is Exceeded

The noise protection report must propose mitigation measures:

• Noise-reduced night mode: RPM/pitch reduction 22–06 h, documented in the manufacturer mode (e.g. "Mode 3"). Reduces L_WA by 2–6 dB. Yield loss 1–4 % p.a.
• Alternative turbine selection: switch to a type with lower L_WA or a certified quiet mode
• Layout adjustment: move critical turbines further from the immission point
• Receiver-side noise protection (sound-insulated windows): theoretically possible, rarely applied in practice

Peak Level Criterion (Section 6.1 Sentence 2)

Individual short-term noise peaks may not exceed the threshold by more than 30 dB(A) during daytime and 20 dB(A) at night. For wind turbines, this is practically never relevant because the noise is continuous and even.

Tonal and Impulsive Character

If the turbine produces tonal or impulsive noise (e.g. gearbox whine, "thumping"), a surcharge of 3–6 dB is added to the assessment level. In modern wind turbine technology, this has been practically eliminated; it was relevant for some older gearbox types.

Pre-Existing and Additional Noise Load

If the pre-existing noise is less than 6 dB below the threshold, the WTG may be added as long as the total does not exceed the threshold. If the pre-existing noise is already at the threshold, the WTG may contribute practically nothing. This is critical at sites near commercial areas or railway lines.

Acceptance Measurement After Commissioning

The permit almost always includes the condition of an acceptance measurement within 6 months after commissioning. The actual sound power level of the built turbine is checked against the value used in the prognosis. If there is a deviation, retrofitting or night-mode adjustments are required.

Frequently Asked Questions

What about infrasound?

TA Laerm only covers the audible frequency range (16 Hz – 16 kHz). Infrasound (< 20 Hz) is not captured. Studies (e.g. UBA 2020, "Mensch+Umwelt") show no health effects below the perception threshold. For low-frequency components (8–100 Hz), DIN 45680 applies but is rarely required in WTG permitting procedures.

Does TA Laerm apply to the construction phase?

Yes, but with separate rules (AVV-Baulaerm). Construction noise is assessed differently from operational noise — mitigation measures are required when thresholds are exceeded, but higher tolerance applies given the temporary character.

Is there a TA Laerm revision 2024/25?

TA Laerm has been under revision for years. As of 2026, the 1998 version still applies unchanged with minor amendments. The expected key change: updated methodology for pre-existing and additional noise load assessment.