Johns Manville recently hosted a live webinar with SLR Consulting addressing the key components to developing an acoustical strategy to mitigate unwanted noise in industrial environments. You can watch a full recording of the webinar here.
Our co-hosts, Doug Fast, from Johns Manville, and Pascal Everton, from SLR Consulting discussed everything from acoustical testing to material selection. If you didn’t get a chance to attend, don’t worry, we’ve distilled the presentation into the 5 key takeaways regarding industrial acoustics:
- It’s important to distinguish between “insertion loss” and “transmission loss.” These two concepts can often be confused as they both refer to a sound level reduction as sound passes through a material or assembly. Insertion loss, however, measures the difference between a treated and untreated system. While transmission loss measures the decrease of sound power through an element.
- There are several key factors that affect the sound-absorbing performance of a material. You’ll find that fibrous materials like fiber glass or mineral wool are very effective at reducing sound because of their fiber diameter. Similarly open cell materials will also have relatively effective noise-reducing performance. Other components that influence noise reduction properties are the bulk density, material thickness, and porosity of the material.
- When we target sound control, we should start by addressing sound at the noise source when possible. Pascal took us through a variety of acoustical controls that could be implemented at various noise sources to help reduce unwanted noise.
-Pumps, Compressors, Blowers, Motors, etc.: Acoustical blankets or enclosures
-Piping: Acoustical pipe lagging, silencers
-Aerial Coolers, Fans: Fan blade selection, variable frequency drives (VFD)
-Air Intakes, Exhausts: Silencers
-General Noise: Barriers or buildings
- Material facings can negatively impact acoustical performance. At lower frequencies, facings (like FSK or ASJ) on a material have relatively little impact on acoustical performance; however when noises move into the higher frequency range, facings can actually begin to reflect the sound, working against the noise-reducing performance of the insulation.
- Specifiers should emphasize material thickness when designing acoustical control systems. At the lower frequencies that will typically be encountered in industrial settings, the material thickness has a greater influence on sound absorption than the material’s density does. While it may seem reasonable to assume that a denser material may make it more difficult for sound to pass through, the simple fact is the material’s thickness will be more influential in acoustical performance than its density.
Pascal and Doug covered many more topics in their presentation, including the test methods for field and lab testing, how to address high-vibration environments, and the fundamental principles of sound control. To see the entire webinar, click here.
