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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

Frequently Asked Questions

What is the FERC 55 dBA Ldn noise limit?

FERC requires that compressor stations and gas facilities not exceed a day-night sound level (Ldn) of 55 dBA at the nearest noise-sensitive area.

What does this noise propagation calculator do?

It calculates the sound level at a given distance from a noise source to determine FERC Ldn compliance at the property line for compressor stations and gas facilities.

What is Ldn in noise measurement?

Ldn (day-night average sound level) is a 24-hour noise metric that adds a 10 dB penalty to nighttime sound levels to account for increased sensitivity during sleeping hours.