Noise Curtains

by dB Engineering

Custom Composite Quiets Compressor Station

Over 800 sound absorption/barrier panels in 50 different sizes line the interior of this compressor station.

This compressor station houses five 1400 horsepower compressors. Because of the noise they generated, the compressors were causing serious problems for the gas company with their next door neighbors.

The homeowner's complaints to the local government and press created an adverse public relations climate so the gas company decided to investigate the noise problem and figure out what could be done to remedy the situation.

Independent testing showed that the compressor station was generating sound levels up to 60 dB(A) at the boundary line. Further testing revealed that the dominant noise sources were low frequency, which are always more difficult to attenuate than high frequency noise.

To comply with local and state ordinances and clear the way for future expansion, the gas company needed to reduce the noise level at the property line from 60 dB(A) to 50 dB(A) by treating the building, rather than individual compressors.

Their reasoning was that employees must have unrestricted access to the compressors and clear visibility throughout the building.

Application engineers recommended lining the walls and ceiling with a sound absorption/barrier composite. The composite, made up of quilted fiberglass and a 1 lb./sq.ft. barrier, would do double duty for the gas company by absorbing airborne sound waves and increasing the transmission loss ability of the building. Leaks at the seams of the panels would be prevented by using a velcro attached noise barrier batten.

After testing and the development of a new time and money-saving installation technique, manufacturing over 50 different sizes and configurations of the composite panel began. More than 800 panels were made to line the interior of the 40' wide x 179' long x 28' high building.

Post-installation testing showed that the solution performed better than the promised results.

This diagram shows a cut-away view of the acoustical treatment.
The noise level at the property line was reduced from 60dB(A) to 45dB(A). 5dB(A) lower than what was specified. And while noise levels within the building were not as critical, gas company officials were pleased the employees could now hold a conversation without shouting.
In addition, the gas company found that the light colored fabric facing used dramatically improved the lighting inside the building.

Town officials quickly expressed their pleasure with the decrease in noise. And the neighbor who shares the property line called the gas company officials to thank them.

Table showing how the human ear perceives noise reduction.

Decibel Reduction Reduction Experienced by Ear
2 15%
4 23%
6 38%
8 48%
10 56%
12 63%
14 68%
16 75%
18 77%
20 81%