The Noise of Fracking

Last week, NPR ran a story on the sounds of natural gas compressor stations – the infrastructure used to move gas out of wells and along pipelines (a longer version is available here). As NPR noted, while levels may stay within the decibel range established by local regulations, those ordinances do not take into account how the constant humming produced by stations affects residents.

Partly because of their excessive noise, compressor stations have become a particular focus for local residents and environmentalists concerned over the growing pollution caused by fracking. While energy companies have attempted to blend such stations into surrounding neighborhoods (see this completely-serious-and-somehow-not-an-Onion video from Chesapeake Energy), the sound levels created by the stations remain obtrusive.

One major issue that the NPR story and the video by Chesapeake Energy neglected to cover was the sound created by what are called blowdowns – the release of natural gas from a section of pipeline. Energy companies generally activate blowdowns when sections of pipeline need to be repaired. Blowdowns are also used to vent gas when pressures reach unsafe levels.

TransCanada provides this corporate propaganda helpful factsheet for local residents interested in understanding just what, exactly, is causing the sound they can't help but hear. Here's how TransCanada describes the process: "This gas release is similar to letting air out of a car tire: the most forceful rush of air occurs at the very beginning, then the flow gradually slows down. The first 30 to 60 minutes of the blowdown are the loudest, but the entire blowdown may last up to three hours." Natural gas typically travels through pipelines at a compression rate somewhere between 800 to 1400 pounds per square inch (5,500 to 9,500 kiloPascals), resulting in a gas plume that can reach heights of 200 feet. 

A quick YouTube searched discovered numerous videos of local residents filming and monitoring the sound of blowdowns. First up is a recording from Ohio, where in 2009 user alfbe4 measured the decibel levels emanating from his neighboring station with a noise dosimeter. Decibel levels exceeded 90dB (i.e., if you listen to this, turn down your volume).




And user Leland T Snyder uploaded this 13-minute video last July:




While the sound levels of the compressors can be limited by the federal government to 55dB, there appear to be no limits on the sound levels of blowdowns. If anyone knows more about this, let me know. The videos above are several years old, and I'm wondering what has changed - if anything - in recent years.