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Noise Propagation Calculator

FERC 55 dBA Ldn Compliance

Professional Noise Propagation Calculator
Calculates sound level at distance using inverse square law with atmospheric absorption. Determines FERC compliance at Noise Sensitive Areas (NSA).

Source Parameters

dBA
ft

Distance to NSA

ft

Operating Schedule

Ldn adds 10 dBA penalty to nighttime noise

FERC Noise Requirements

  • 55 dBA Ldn at any pre-existing Noise Sensitive Area (NSA)
  • 10 dBA increase penalty applied to nighttime (10pm-7am) operations
  • NSA includes residences, schools, hospitals, and similar occupied buildings

Standards

  • FERC
    55 dBA Ldn at NSA
  • EPA
    Levels Document 550/9-74-004
  • ISO 9613-2
    Sound Attenuation Outdoors