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The FERC 55 dB(A) Ldn Requirement - Introduction

The FERC 55 dB(A) Ldn Requirement - Introduction

The Federal Energy Regulatory Commission ("FERC" or "Commission") noise limit of 55 dB(A) Ldn is the only game in town when it comes to placing environmental sound level limits on oil and gas transmission facilities at the federal level. If you work on projects involving gas compressor stations or LNG facilities, then it is worthwhile to understand what this noise limit is and how it works in practice. The regulatory landscape for environmental noise from industrial facilities was covered in my previous blog post. Throughout the next several posts, we are going to take a deep dive into the ins and outs of the FERC noise limit, in bite-sized noise control morsels.

We will cover:

  • Nomenclature
  • Why the Ldn causes so much confusion
  • The 48.6 dB(A) Leq Equivalence Assumption
  • The Great Distinction and Why It Matters (or might not)
  • The Regulation versus the Application of the Regulation
  • Practicalities, Pre-Certificate
  • Practicalities, Compliance
OK. I get it. Noise is not your thing, but here's a quick test. Have you ever thought or said any of the following?

  • I am not an acoustical expert.
  • I didn't have a noise control engineering course in school.
  • I have a consultant or someone on staff who handles noise issues.
  • Noise is such a small part of my project, I can worry about later, or when it turns out to be a problem.

If you have ever thought or said the last statement, then I strongly encourage you to read my second blog post, "Should I Consider Noise Control on Every Project?" If you have thought or said any of the above statements and you work on fixed facility projects, particularly in the oil & gas or power sectors, then I encourage you to keep reading.

We learned in my last post that if your project isn't FERC regulated, oftentimes there is no noise regulation. In the absence of a noise regulation you may still want to have a good neighbor policy noise goal in order to minimize the potential for noise complaints. If so, you should understand the FERC noise limit; it is a great, defensible benchmark. If you demonstrate that you went through the effort and cost to meet the FERC noise limit even if you didn't have to, then you can make a very strong case against noise-based lawsuits. Even if you do not adopt the FERC noise criteria, then understanding it will give you a good basis for setting project noise expectations, and potentially avoiding common pitfalls.

I suppose I could end this introduction with a little background on the history of the FERC noise limit. However, I think I will save that for another time. Suffice it to say, it goes back to The Natural Gas Act of 1938. For now, I hope this introduction has piqued your interest enough to warrant further reading. Even though it might be a little outside of your wheelhouse, I believe that having an understanding of the FERC noise limit will provide enough context to serve you well on all of your projects that might have a noise component, which could be all of them.

About the Author - Tim Simmons, Ph.D. - USSI Director of Industrial Acoustics
Tim Simmons manages USSI's Acoustics Division. Tim comes to USSI with an immense background and knowledge in Acoustics and Noise Control, including software noise modeling. Tim holds a PhD in Physics and Astronomy from the University of Mississippi; and a B.S. in Engineering Physics from the University of Tennessee.