Mechanical Background Sound in Exam Rooms
January 2010 held a highly anticipated milestone for acoustical consultants. The definitive guide called 2010 FGI/ASHE Guidelines for Design and Construction of Health Care Facilities has a greatly expanded acoustics section in this year’s edition. The section went from a solitary partition transmission loss table in prior issues to an eighty page guideline that comprehensively covers exterior noise, acoustical finishes, background noise, sound isolation, vibration, sound masking systems, audio systems and alarms. As a result, acoustical consultants are hoping that architects and engineers will appreciate the breadth and importance of acoustics and consequently incorporate acoustical design early in a project when it is most cost effective. (more)
Anechoic Chambers – What They’re All About
So what in the world are anechoic chambers? In short, they are the consultant’s and manufacturer’s best friend when it comes to acoustics. Anechoic chambers are primarily used for a variety of acoustical measurements that determine just how much noise a product is making. These chambers are most notable for their strange appearance… their foam filled walls, ceilings, and sometimes floors of spikes look a bit like a Nerf torture chamber; if you filled them with plastic balls they’d be a hit attraction at your local Chuck E Cheese. But alas the soft spikes are not meant for harm or play but rather to absorb as much sound as possible, so that you can measure the true sound emitted or reflected off of whatever noise source you are interested in. (more)
How to Gradually Reduce Employee Noise Exposure
Industrial plants are most often loud and dynamic work environments. Noise fields are complex with varying levels of noise produced by many different pieces of equipment, and employees spend varying amounts of time near the different noise sources. Sound levels are even impacted by the building, with taller spaces generally quieter than single story spaces, sound absorbing room finishes sucking up some of the noise, and partitions blocking sound. Measuring worker noise exposure is simple. (more)
Noise Isolation for Hospital Mechanical Rooms
Hospitals and Healthcare Facilities have requirements for large volumes of ventilation and strict control of airflow, and the greater the airflow, the greater the potential for noise. Building mechanical services equipment, fans, pumps, cooling, and heating equipment are all sources of high noise levels. When Acoustics By Design works on a new hospital, we typically expend half of our effort on attenuating building mechanical systems noise. In order to avoid the need for extensive noise and vibration isolating constructions, project designers and engineers should pay careful attention to mechanical room sizes and locations during schematic design. Here are some issues to address early on… (more)
Tunnel Vision | Highway Traffic Noise Wall Barriers
On a recent trip to Chicago, my wife and I were thankful for all the new traffic lanes recently completed. I can remember when the trip back home to my folks took an extra couple of hours if I got stuck in all the traffic. But thankfully, with the new highway renovations, we’ve actually had some easy trips with no more traffic backups. Of course, our easy traveling must come at a cost. High density population areas are often encroached upon by the infrastructure needed to support them. In our case, the highways got a lot bigger with more lanes but that meant that they were even closer to the houses and neighborhoods that we drove through. (more)
Wind Turbine Noise | Residential Vs. Commercial
Who Can See the Wind?
(by Christina Georgina Rossetti)
Who can see the wind? Neither you nor I
But when the leaves are trembling
The wind is passing by!
Who can see the wind? Neither I nor you
But when the trees are bending low
The wind is passing through!
As this children’s poem points out, the wind’s affect on the surrounding environment is a beautiful thing. But if you live near one of the many “wind farms” popping up all over the country, you may disagree. If that’s you, then “seeing the wind” means 400 foot tall wind turbines interrupting your landscape, and “hearing the wind” may mean loud “whirring” and “whoosh” sounds keeping you awake at night. (more)
Psychoacoustics: Annoyance from Tonal vs. Broadband Sounds
For today’s topic, let’s think of driving our car with the wind rushing by, when all of a sudden our attention is drawn by that annoying squeak coming from the dashboard. The changing of the squeak with time was the topic of a recent blog, but this time we’ll examine its tonal nature. (more)
Acoustics for Video Venues & Portable Churches
From mega-churches to small town congregations, the video-venue concept is becoming a staple of church growth. For those not “in the know”, a “video-venue” is a church meeting where parts of the service (typically the sermon or message) are piped in via video signal and projected on a large screen, while other parts of the service (like the music or announcements) are done live. Since the sermon is filmed in the “main sanctuary”, it can be broadcast to different rooms within the same church building (onsite video-venues) or to campuses across town, out of state, and beyond (offsite video-venues). As a devoted church member and as an acoustical consultant, I have experienced many different types of video venues firsthand, and I have found a common thread of acoustical “challenges” they typically face. If you are planning a video-venue or portable church ministry, here are some important items to consider before selecting your new space… (more)
Your Conversation with your Doctor may not be as Private as you Think
While I was at the doctor’s office the other day, I was allowed to listen to a conversation between a doctor and another patient. Was I in the room with them? I didn’t have to be. The sound isolation between exam rooms was so poor that I could hear virtually everything that was said. (more)
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An Opportunity Lost? GM’s Saturn Division – Success Squandered or Just Delayed?
Early in my career, I was a young acoustics engineer working at the General Motors “Noise and Vibration Laboratory” (NVL) where our function was to provide automotive noise and vibration control solutions to the various vehicle development teams. At one point, my job was to lead the design and development of the noise control (”Sound Package”) solutions for the original Saturn vehicle line. So when I saw the recent news about Roger Penske & Penske Automotive Group acquiring the Saturn brand from General Motors, I found myself thinking back on the glory days of Saturn: what made them so unique, and what solutions will bring them through the current economic recession? (more)
Sick of Loud and Noisy Patient Rooms? We Are Too.
You don’t have to spend a lot of time in hospitals to find out that patients are sick of the noise in their rooms. Press Ganey surveys, current literature on the subject, and the unsolicited comments we receive while measuring sound levels in hospitals all confirm that patients are most often displeased with the noise experienced in hospital patient rooms. Minimizing noise disturbance to patient rooms is an important aspect of acoustical design for healthcare facilities. But before we can reduce the noise levels, we need to know the sources of noise and understand the factors that influence its transmission. (more)
Noise Pollution from Wind Energy – Why It’s a Problem!
With today’s heightened awareness about energy and our dependence on foreign oil, we are being lured with a promise of bountiful, cheap electricity if we simply harvest the energy from the wind. As is true with everything in life, “there is no such thing as a free lunch”. Communities across the country are learning from past mistakes (the hard way) that one of the greatest struggles with wind turbine development is in community noise disturbances – or noise pollution. So, what can be done about it? (more)
The Problem with Pulpers | Noise and Vibration Control
We were recently called in to assist in addressing a noise issue that was the result of a university’s desire to be more “green”. In this case, we were asked to assess the noise produced in the dish wash room of a university student union. This blog is the second of a two-part post about student union acoustics, and you may want to read the first blog on College Campuses and Student Union Acoustics before continuing. (more)
If It Sounds Like Noise to You, It May Be “Esion”
Fundamentally, sound is “that which we hear”. What we hear at any given time can greatly influence us. We use sound to communicate, to express warning, fear, pleasure and excitement. Some sounds can relax us and help us fall asleep, while other sounds can distract us and make it more difficult to perform simple tasks. Different sounds can be soothing and pleasing or annoying and irritating. Accordingly, determining “What is sound?” and “What is noise?” can become a highly subjective task. As engineers and scientists, it’s our job to generate generalized models that have a high level of correlation to humans (or to specific populations). (more)
When One Size Does Not Fit All | Diffuser Sound Levels
On a recent trip to India, I discovered a cute clothing sizing term called “free size” which is equivalent to “one size fits all”. Free size clothing must be a manufacturer’s delight since production and distribution are greatly simplified. Adjustments to the size of the garment are typically made through waist ties of various designs and if needed, permanent alterations.
In the A/E/C industry, diffuser, grille and register (air device) manufacturers have chosen the free size philosophy when it comes to providing sound data. (more)
College Campuses and Student Union Acoustics
At Acoustics By Design, we regularly consult on the design of College and University buildings including classroom buildings, dormitories, athletic facilities, performing arts buildings, libraries, research buildings, and student centers. These numerous building types result in our needing to address a myriad of acoustic and vibration issues. Many student centers and student unions face a similar problem: loud noise from the commercial kitchens inhibit the relaxed social environment for the students. Universities want their student unions to be a center for campus life and activity, and if the student center is too loud to provide the desired environment, students will inevitably congregate elsewhere. (more)
Elbows vs. Sound Attenuators: Interchangeable?
It is common belief that a series of elbows near an air handling unit (AHU) can accomplish the same insertion loss as a manufactured duct sound attenuator. It’s true that elbows are less expensive than sound attenuators, but what acoustical performance is really achieved with this “low cost” substitution?
Let’s compare the two designs. Using the tables presented in the 2007 ASHRAE Handbook – HVAC Applications, for any type of elbow (round, rectangular, acoustically lined or not), the width of an elbow (in the plane that it turns) must equal or exceed 30 inches to get ANY insertion loss at 63 Hz. A 30 inch wide elbow provides only 1 dB of insertion loss (IL) at 125 Hz . These two frequencies are typically of concern when reducing sound from AHUs.
Why Courts Need an Expert Witness in Acoustics
Our company president, Kenric Van Wyk, was recently featured in a Wood TV 8 interview as an expert on noise levels. The local NBC affiliate was covering a story on a teenager who had been killed by a train after walking down the tracks while listing to an MP3 player through ear buds. We brought one of our noise meters down to the tracks and made measurements while a train went by, and the story made the evening news. (more)
Rooftop Roulette | Noise and Vibration Isolation for Air Handlers and Mechanical Units
Over the years as an acoustical consultant I’ve seen a lot of architectural firms locate rooftop air handling units over or near acoustically sensitive spaces; then they put up resistance to doing the necessary extensive noise controls that are needed for such a situation. The protest usually includes “but we’ve never had to do that in the past…” I call this rooftop roulette, because while not incorporating noise control design may have worked in the past, it does not guarantee future success. (more)
Perception Vs. Reality: What Our Ears Hear
It seems like everyone is talking about decibels these days: “5 dB of this” and “3 dB of that.” As acoustical consultants, we hear people using these metrics and often wonder to ourselves, “Do they really know what a decibel is?” Occasionally, someone is brave enough to ask the more important question, “Just how much is a decibel?” The answer to that question is, of course: well, it depends. Are we talking about physical sound levels or perceived sound levels? There is a big difference! (more)
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