Implementing an industrial acoustical control strategy goes far beyond selecting an insulation with a high NRC (noise reduction coefficient) value. There are nuances and details that are key to understanding the acoustical needs of the system and selecting the appropriate materials to address those needs.
To help you learn more about developing an effective acoustical control strategy, Johns Manville is co-hosting a live webinar with SLR Consulting on October 25th, at 2:00 PM ET. The webinar, Understanding Industrial Acoustics: A Sound Strategy, will be presented by Pascal Everton, a Principal Acoustical Engineer at SLR consulting, and Doug Fast, a Senior Research Engineer at Johns Manville.
In anticipation of the upcoming webinar, we sat down with Pascal to discuss his insights and perspectives regarding industrial acoustical control – specifically, we wanted to know what Pascal had to say about the latest in testing, technology, and acoustical system design.
- Can you give me a few details about your background, what SLR Consulting does, and your role at the company?
I’ve been consulting in acoustics for over 15 years in a wide variety of industries. I am a registered Professional Engineer, and I am a member of the Institute of Noise Control Engineering (INCE). SLR is the consulting firm I work for, and it is an environmental consulting and advisory services company that offers technical expertise in over 30 disciplines. We have over 70 offices spread across the globe, and my role is that of Canadian Acoustics Discipline Manager.
- How critical would you say acoustical control is in industrial applications?
From an environmental noise standpoint, properly designed noise control is very critical. If a facility’s noise level is not in compliance with the regulatory limit, the operator could be forced to reduce operations or shut down entirely until the noise levels are compliant. From an occupational health and safety standpoint, it is well known that exposure to high noise levels can cause permanent hearing damage and other adverse health effects.
- Are there any new technologies on the market that can help control unwanted noise?
There are often modifications to existing products or enhancements made to materials to make them more effective in specific applications (e.g. high temperatures). However, there has not been much technological advancement in industrial noise control in recent years. The advancement comes mostly in the form of companies testing and publishing reliable noise reduction results from new material configurations.
- Do you ever see noise as a result of inefficiencies or flaws in the process or application?
There are many areas where an inefficient process can lead to noisy conditions. For example, cavitation can cause significant additional noise. Cavitation is the formation of small bubbles in a liquid due to a low pressure area. As the bubbles collapse, they generate a popping sound, and the force can damage metal components. This is often seen in ship’s propellers, but can happen in pumps, pipes and other equipment. Since cavitation can be very damaging to equipment, designers and process engineers try to prevent it from occurring for several reasons, not only to reduce noise. Another example would be running fans from aerial coolers at high speeds do to inefficient fan blade design. Noise from aerial coolers can often be reduced by slowing the speed of the fan. This can be achieved with Variable Frequency Drive (VFD) controllers, or using a more efficient fan blade design combined with slowing the speed of the fan.
- Is field testing important in any application or only under specific circumstances?
Field testing is important once a newly commissioned facility comes online to verify that sound levels from equipment were accurately predicted, and that equipment with vendor-guaranteed noise levels meets the specified noise levels in each frequency band.
In the case of reducing noise from an existing facility, it is important to measure the current conditions in order to establish the amount of noise control that is required to reduce the overall facility noise to the mandated level.
- What are three steps designers can take to ensure their noise control is up to par?
The first step is to consider the cumulative noise from the entire facility, as opposed to the isolated contribution of noise from individual components. This requires a noise model to be created which accounts for propagation effects, shielding from buildings and structures, source directivity, etc. This model also needs to include noise from auxiliary components such as piping, steel support structures, noise through building walls, vents, etc. to evaluate the cumulative noise from the entire facility in operation.
Once the model is established, the second step is to evaluate the areas where noise control will be necessary. That can mean coordinating with various vendors to discuss noise control options for their equipment, or it could mean incorporating noise control elements into the design (e.g. pipe lagging, equipment blankets, silencers, etc.). These noise control elements should be well-defined with detailed specifications and material requirements to ensure that contractors don’t inadvertently install incorrect materials or use incorrect installation techniques which could negatively impact the noise control benefit.
Lastly, once the facility is operating, there should be post-installation verification of the equipment and noise control systems to ensure that everything is installed and operating as required and expected.
- Beyond using insulation as pipe lagging, are there other tools or resources people could use to help control noise in their facilities?
There are several options available for noise control depending on the type of noise source, its location, and the amount of noise reduction required. Some other common noise control options are acoustical blankets that are custom designed for a secure fit around various types of equipment. The advantage being that these blankets are removable for equipment maintenance. Custom rigid enclosures can also be designed for some equipment and can be designed to be removable as well. Other common noise control solutions are silencers, barriers, and acoustical buildings, each of which have various limitations as well as their own set of advantages and disadvantages.
Join Pascal and Johns Manville's Doug Fast on October 25th, at 2:00 PM ET for their live webinar, Understanding Industrial Acoustics: A Sound Strategy, to learn more about creating a noise control strategy that can address the unique needs of your application.
