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Acoustics is instrumental in creating spaces that support employee wellbeing, engagement and productivity

December 16, 2019

The late Steve Jobs famously observed that “Design is not just what it looks like and feels like. Design is how it works.” His insight into the importance of both form and function is what has kept Apple at the forefront of the tech industry, and the same can be said for the world of interiors.

The firms and designers who understand that aesthetics and functionality go hand in hand and inform each other are the ones that typically succeed in creating inspiring spaces people want to inhabit. And yet, when most people consider a well-designed space, the emphasis remains on how it looks. For too long, design has focused on our sense of sight (as well as touch) and neglected how a well-designed interior sounds. Nowhere is this more obvious than in the workplace today.

The ubiquitous open office plan was initially heralded as the solution to improving collaboration and productivity, not to mention freeing generations of employees from working in cubicles. However, as time and experience have revealed, the open plan concept isn’t as healthy or effective as we once thought.

It’s not that open offices aren’t beautiful and offer employees more functional, ergonomic furniture or more appealing break rooms and lounge spaces. It’s that they’re simply too noisy. In fact, multiple studies and reports demonstrate that noise levels are the single biggest complaint among office workers today. While no one is arguing for the reestablishment of cubicle farms, the noise problem isn’t going away. Noise-cancelling headphones aren’t the solution because they undermine the ability of employees to collaborate, which open offices were designed to do.

Is unwanted noise really that big of a deal? Does it make that significant of a difference in the well-being and productivity of the occupants in a space? This CEU will answer those questions and others and will review the basic principles of effective acoustics; it will examine the wellness trend and how interiors can be designed to improve wellbeing with regards to sound; it will take a closer look at productivity and engagement and how they can be improved through the design of the workplace; and it will offer insight into how the materials specified in a space can help improve acoustics and, thereby, the wellbeing of occupants in the workplace, healthcare settings, educational institutions and beyond.

The High Price of Noisy Environments

As noted earlier, the open office is the predominant model for the design of the workplace today. By 2014, nearly 70% of all offices reportedly featured open floor plans1. And while the open office is here to stay, the noise problem seems to be as well, which comes with a heavy price tag.

According to the 2019 “What’s That Sound?” Workplace Acoustics Study from Interface, noisy offices increase levels of stress and anxiety for employees, and more than half of respondents indicated that noise levels would impact their decision to accept a job at a company2.

The report identified the most common causes of office noise that disrupt people’s work in the U.S., U.K. and Australia. For American employees, the biggest sources of unwanted noise are: co-workers talking to one another (76%), talking on the phone (67%), phones ringing (65%), people walking around (56%) and printer/fax machines in use (45%). (Note: Keyboard clicking was not identified as a source of distraction in the U.S. but 47% and 39% of those surveyed in the U.K. and Australia, respectively, considered it unwanted noise.)

All this noise is more than just annoying or irritating; it negatively impacts workflow and productivity as well. Here’s why: simply put, noise disturbs concentration, and that’s a big deal when people spend more than half of their time performing tasks that require concentration, according to architecture and design firm Gensler3.

There’s a kind of irony at play here as well, in that most workers struggle to concentrate in open plan environments that were designed purely for collaboration4. Further, while people can adapt to the steady sound of background noise (or “white noise”), what impedes productivity most often in the workplace is interruptive noise. Researchers at the University of California, Irvine discovered that employees get interrupted every 11 minutes and aren’t fully able to refocus on their tasks for another 25 minutes, resulting in more than 2.5 hours lost to interruptions each day per employee5. These distractions equate to roughly $650 billion in losses to American companies each year, according to a Business News Daily report.

It gets worse. By monitoring the brain activity of workers in open plan offices, one study concluded that employees are up to 66% less productive when exposed to just one nearby conversation6. Likewise, the Center for the Built Environment found in a post-occupancy evaluation of 15 buildings by more than 4,000 respondents that more than 60% of occupants in cubicles believe poor acoustics interfere with their ability to get their jobs done7. It seems even relatively small levels of unwanted noise can cause stress and hinder employees’ performance. Gary Evans, a professor of environmental psychology at Cornell University in Ithaca, New York, noted that employees working in a noisy office are 40% less likely to solve technical or functional problems. And when compared with those working in quieter environments, they are also like to make only half as many ergonomic adjustments to their workspace than their counterparts8.

The reason noise poses such a problem for people is because it’s a constant source of stimulation that is difficult to ignore because the human ear is always in receiving mode. “The only solutions are room acoustics measures, modern telephony technology, and good spatial planning,” according to the Interior Business Association9. In the next section, we’ll review the basics of acoustics and spell out some common terms and definitions that are relevant to understanding acoustics.

A Primer on Acoustics

If noise is the enemy in the workplace and other interior environments like hospitals and schools, then it’s logical to assume that silence is the ultimate ally. Interestingly, when it comes to addressing noise issues or controlling sound in a space, total silence isn’t the end goal. A completely silent room like a recording studio can be a somewhat uncomfortable place to occupy, because sound is a part of our senses and is present in every environment we inhabit. Therefore, the complete absence of sound in a space can feel unnatural.

Sound only becomes noise when it’s not controlled. The aim isn’t to eliminate sound completely, but rather to balance and correct it. To conquer acoustic challenges, it’s important to “understand the enemy,” as it were. As such, knowledge of how sound works will play a key part in overcoming and preventing acoustical issues from happening.

Let’s start with the obvious and define what we mean by “sound.” In physics, sound is a vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the reception of such waves and their perception by the brain.

Humans can only hear sound waves as distinct pitches when the frequency lies between about 20 Hz and 20 kHz. Sound waves above 20 kHz are known as ultrasound and are not perceptible by humans, and likewise sound waves below 20 Hz are known as infrasound and are also unreceptive to the human ear10.

Essentially, sound frequencies are divided into three main categories: low, medium and high, each with its own type of wave. Low frequencies mean fewer waves are occuring per second, which makes each individual wave longer, larger and more extended. Similar to waves in an ocean, they are more difficult to absorb than the small, rippled waves seen in higher frequencies.

All the sounds we hear have a certain frequency. Acoustic discomfort occurs when there is an imbalance between these frequency catagories, so the goal is to absorb the right amount from each to create balance. In today’s interiors, the main focus should be to absorb human speech frequencies which hover from 500 Hz to 1000 Hz in most cases.

Reviewing the ABCs (and D) of Acoustics

While the principles of controlling acoustics in interiors can be broken into a few basic categories, the process of successfully addressing noise can be a complicated undertaking. The science of acoustics is complex, and therefore, enlisting the help of an acoustic expert is prudent and recommended. 

Likewise, effective acoustical design is not a one-size-fits-all strategy by any means. But following the ABCD principle­—Absorb, Block, Cover and Diffuse—is a useful rule of thumb to follow11.

  • Absorb. The principle of sound absorption is used to determine the amount of sound that needs to be “soaked up” or absorbed in order to reduce the amount of sound being reflected throughout the space. In other words, the culprit is reverberation when sound bounces off hard surfaces. The idea is to use sound-absorbing products such as acoustic panels to help minimize the amount of reverberation taking place.

Acoustical consultant Benjamin Wolf of ABD Engineering & Design notes that absorbing all sound isn’t the solution to the problem of reverberation. Rather, it’s about soaking up the optimal amount of noise. “We don’t simply add as much absorption as possible. Too much absorption can make a space sound ‘dead,’ which can be unnerving,” he says.

While acoustic panels don’t guarantee complete speech privacy (even those with high NRC ratings), they make a significant impact in rooms with many hard, reflective surfaces such as open offices.

Not every space can use wall mounted panels, however, so in those cases, acoustic panels can be utilized in the ceiling plane, which offers good coverage because it is as large as the floor plate and sound often bounces off of hard ceilings. While not every surface can feature acoustic panels, a good rule of thumb to follow is to utilize these products in two adjacent surfaces, which can be very effective at absorbing unwanted sound.

Additionally, upholstered room dividers and partitions with absorptive backing material can also be effective in spaces where wall or ceiling panels can’t be installed. Many of these products are also movable, which provides the added benefit of flexibility and additional visual privacy.

Further, a leading acoustic manufacturer has also developed acoustic textiles that utilize soft, interwoven polyester acoustic fibers that are effective in helping to achieve acoustic comfort in interior spaces. The patented technology allows interaction between the fiber and air, which helps control reverberation while adjusting the environment’s acoustics with precision. The choice of different materials and installation modes allows for selective absorption at precise ranges (low, medium, high) or a more uniform absorption at all frequencies.

  • Block. The same rule that applies to absorption is applicable with blocking: not all sound should be obstructed from traveling within a space, but rather, it’s about impeding the ideal amount of the right sounds in the most effective way. The challenge with blocking sound has less to do with reverberation as with transference between rooms. Sound- blocking materials with high STC ratings can be specified in walls, carpet and workstation panels, for example, but it can be challenging in open offices were partition heights are low, according to Wolfe.
  • Cover. In noisy environments such as an open office, or schools or hospitals, sound masking products and systems that create white noise can be an effective way to eliminate distractions and create speech privacy when covering is important. This is done with sound masking. In other words, if a space doesn’t contain sound-absorbing or blocking elements, the danger is adding additional noise to a room with nothing to absorb it and making the problem even worse. As such, acoustic products should be used in tandem to achieve the desired effect.
  • Diffuse. In acoustics and architectural engineering, diffusion is the efficacy by which sound energy is spread evenly in a given environment. A perfectly diffusive sound space is one that has certain key acoustic properties which are the same anywhere in the space. A non-diffuse sound space, on the other hand, would have considerably different reverberation time as the listener moved around the room. In other words, noise isn’t just about the source of the noise, but it’s the reverberation. It’s the way it’s traveling back and forth and just doesn’t seem to go away. In some restaurants, for example, owners want to create a buzz and they want to have an energetic vibe, but sometimes there’s simply too much noise. So, diffusion is breaking up the sound by slightly angling a wall so it doesn’t reverberate and echo back and forth, for instance. Noise can also be diffused just through using soft art sculpture or hanging a chandelier.

According to a leading supplier of acoustic solutions, when considering the ABCs of acoustics for interiors, the most important factor to keep in mind is reverberation, measured in reverberation time (RT). Reverberation time is the period it takes for a sound that’s been emitted to no longer be audible (or the time it takes for a sound to decrease by 60 dBs from its original frequency). Sound moves in a space in many directions at once at a speed of 1,125 feet per second, so if a room isn’t properly equipped with acoustic elements to absorb it, the resulting reverberation and echo can cause noise issues.

Technically, echo is classified as an event when a sound wave reaches the ear more than 0.1 seconds after the original sound wave was heard. This explains how sensitive the human ear is to echoes. But echoes don’t need to be eliminated completely, they only need to be controlled.

Reverberation time is the most common measure of comfort when it comes to interior acoustics. There are several strategies that can be used to achieve acoustic comfort, including understanding the properties of different materials and their NRC/STC ratings, which we’ll review in detail in a later section.

The Wellness Paradigm

Given the fact the humans spend a majority of their time indoors, it’s no wonder that the industry is beginning to take a much closer look at the impact that buildings have on occupant health. Wellness is one of the most significant trends in decades and is changing the way we view the world—from the products we purchase to the buildings we inhabit.

To be sure, the global wellness trend is among the largest and fastest growing industries, outpacing global economic growth by almost double (6.4% vs. 3.6% respectively between 2015 and 2017)12. The wellness market is currently estimated at $4.2 trillion annually, penetrating a wide variety of categories, including:

  1. Personal Care, Beauty and Anti-Aging ($1,083 billion)
  2. Healthy Eating, Nutrition and Weight Loss ($702 billion)
  3. Wellness Tourism ($639 billion)
  4. Fitness and Mind-Body ($595 billion)
  5. Preventative and Personalized Medicine and Public Health ($575 billion)
  6. Traditional and Complementary Medicine ($360 billion)
  7. Wellness Lifestyle Real Estate ($134 billion)
  8. Spa Economy ($119 billion)
  9. Thermal/Mineral Springs ($56 billion)
  10. Workplace Wellness ($48 billion)

The workplace wellness market, specifically, is projected to grow to $66 billion by 2022, according to the Global Wellness Institute (GWI)13. These initiatives aren’t just coming from the top down, either. Most full-time office employees (87%) who responded to a Capital One survey on their attitudes about the workplace agree that it’s important for companies to create programs and spaces that support their employees’ mental health and wellbeing14. However, 90% of workers who have access to workplace wellness programs and services are concentrated in the U.S. and Europe, the GWI noted.

On the flip side, workforce “unwellness” (chronic disease, work-related injuries and illnesses, work-related stress and employee disengagement) may cost the global economy 10% to 15% of economic output each year, the GWI estimates15.

While the numbers may seem high, consider this: employees represent an organization’s largest cost in terms of overhead, more than construction and operating costs combined16. “This statistic includes not only productivity, but also health, happiness and branding impacts. The theory goes that if these factors can be positively impacted, bottom-line savings can be significant,” according to architecture and design firm Stantec.

It’s no wonder then that the architecture and design industry has seen a steady increase in the number of projects built to achieve third-party certifications such as the International WELL Building Institute’s WELL Building Standard and the Center for Active Design’s Fitwel Certification System. To date, there are more than 650 registered Fitwel projects with over 180 projects certified or pending certification, with an 80% increase in projects achieving certification between 2017 and 201817. Likewise, there are more than 1,000 registered projects under WELL, encompassing more than 190 million square feet of real estate projects in 37 countries worldwide18. In fact, 49% of building owners today are willing to pay more for buildings demonstrated to have a positive impact on health19.

Clearly, the wellness movement is here to stay, and as such, it’s vital for designers and specifiers to understand how interiors impact occupant health. The subject is multifaceted and highly technical, so for the purposes of this CEU, we will explore further the role that acoustics plays in wellness and how the aforementioned rating systems address it.

The Role of Acoustics in Wellness

As we’ve established already, sound is a healthy, natural part of the human experience. Prolonged exposure to noise, however, is not. On the contrary, it damages human health by causing a psychological stress response in the body, including a spike in blood pressure and heart rate.

“There are well-established links between long-term exposure to noise and coronary illness and stroke, as well as stress, high blood pressure and other conditions. The noise in question does not have to be overwhelmingly loud: research shows that the danger level is just 65 dB [quieter than a home dishwasher], which is often achieved in lively offices and especially in social spaces like cafés and canteens,” according to an Interface study20.

Research has shown that even intermittent exposure to loud noises can result in negative health outcomes such as long-term stress hormone levels and hypertension21. Obviously, such stressors have a detrimental effect on employee health and productivity, which also can impact a company’s bottom line, as we’ve noted in earlier sections.

Beyond the workplace, however, the ability to mitigate unhealthy noise in settings such as educational and healthcare environments take on even greater importance.

Education Implications

Research has shown that children growing up in noisy homes develop language and cognitive skills more slowly than those who live in quieter homes. Other studies demonstrate a similar effect in classrooms, where students who are exposed to excessive noise fall behind their peers in quieter classrooms22. In one New York City school, for example, students classroom was located near a train track performed worse in reading comprehension (up to a year behind) than their peers on the other side of the school. Interestingly, when the city installed noise dampeners on the train tracks and soundproofing materials in the schools, the lagging students caught up to their peers.

Further, according to Autism Speaks, approximately 1 in 59 children is diagnosed with an autism spectrum disorder (ASD), many of whom suffer from noise sensitivity. This can be particularly challenging in classroom settings, so researchers set out to determine exactly what effect noise had on students on the spectrum.

In one study, four classrooms were identified in two schools based on their noise levels, and behaviors were recorded from 42 participants. Research results indicate that environment is important to the treatment of autism because it influences behavior23. Specifically, the study uncovered a significant, positive correlation between noise levels and frequency of target behaviors among students with autism. As decibel levels increased, several of the observed behaviors occurred with greater frequency.

Overall, the study’s findings suggest that attention to acoustic design and modifications to existing environments are essential to providing a supportive educational environment24. “With decreased arousal and increased neurological resources, individuals with ASD will evidence less stereotypic behavior as a result of lower internal distress,” the study’s authors noted. “Although under some circumstances, individuals with autism may benefit from being acclimated to neuro-typical environments, providing environments that buffer acoustics benefits the learning of individuals with heightened sensory perception and individuals with neuro-typical functioning alike.”

Healthcare Considerations

There are many potentially undesirable outcomes that noise can produce in healthcare settings that range from irritating to harmful for both patients and caregivers and could affect them psychologically and physiologically. For example, a sudden noise can startle a patient and trigger reflexes that may lead to injury, increased blood pressure and/or higher respiratory rates. Patients who are exposed to noise for prolonged periods may also experience memory problems, irritation, impaired pain tolerance and perceptions of isolation. Further, being exposed to noise at all hours can lead to sleep deprivation which has been tied to longer recovery times, falls, dementia, higher re-hospitalization and worse medical outcomes. On the other hand, reduced noise levels in intensive care units have been found to promote better sleep and healing25.


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Learning Objectives

interiors+sources’ Continuing Education Series articles allow design practitioners to earn continuing education unit credits through the pages of the magazine. Use the following learning objectives to focus your study while reading this issue’s article. To receive one hour of continuing education credit (0.1 CEU) as approved by IDCEC, read the article, then log in to take the corresponding exam. To earn 1 learning unit (LU) as approved by AIA, read the article, then log in to take the corresponding exam.

After reading this article, you should be able to:

  • Explain how noisy environments negatively impact their occupants.
  • Define the ABCs of acoustic properties as they relate to interiors.
  • Identify the emotional and psychological impacts of sound on people’s wellbeing.
  • Describe the difference between engagement and productivity.
  • Differentiate between NRC and STC ratings as they relate to acoustic materials.

Additional studies have linked the negative effects of noise with cardiovascular stimulation, hearing loss, increased gastric secretion, pituitary and adrenal gland stimulation, suppression of the immune response to infection, as well as female reproduction and fertility26. The World Health Organization (WHO) recommends that noise levels inside hospital wards should not exceed 30 dBA at night to help reduce sleep disturbance. Unfortunately, recent data reveals that noise levels inside hospitals are much higher than the guideline values. Since the 1960s, the average noise levels inside hospitals have increased by an average of 0.38 dBA (day) and 0.42 dBA (night) per year.

The drawbacks of poor acoustics in medical facilities extend to healthcare professionals as well. While doctors, nurses and other caregivers are trained to perform in high-stress situations, it requires a great deal of energy, which can deplete quickly in environments with high noise levels, contributing to fatigue. Further, speech intelligibility is essential in healthcare environments where doctors and nurses are required to accurately understand and respond to auditory signals or equipment alarms, for example26. Therefore, poor acoustics in these facilities may lead to errors that pose risks to patients.

Lastly, the HIPPA Privacy Rule requires appropriate safeguards to protect the privacy of personal health information and ensure confidentiality of patient information. Speech privacy plays an important role in the process by ensuring that care givers can hold discrete conversations with patients without being heard by unintended listeners.  

Certifying for Wellness

In the past several years, two building standards have emerged to complement the LEED rating system, which focuses on resource efficiency and sustainable design. As noted in a previous section, both the WELL and Fitwel systems have experienced tremendous growth as they employ evidence-based research to create actionable design strategies that positively impact occupant health and wellness.

While these two systems are similar and overlap in scope in many cases, they are also distinct in other focus areas. We’ll briefly review each rating system in terms of how they deal with wellness and, more specifically, occupant comfort as it relates to acoustics.

The WELL Building Standard is helping to revolutionize the design of the built environment. It explores how design, operations and behaviors within physical spaces can be optimized to advance human health and well-being27. Covering seven core concepts of health—air, water, nourishment, light, fitness, comfort and mind—in addition to hundreds of other features, WELL is a comprehensive building standard that can help design professionals address key wellness metrics for projects of all types.

Specifically, WELL addresses occupant comfort as it relates to noise across six different categories28, including:

  1. Exterior Noise Intrusion (Feature 74): Particularly in urban areas, loud or repetitive exterior noises can be a source of stress and a risk factor for certain health outcomes. Studies show that individuals exposed to traffic noise have a higher risk for diabetes, stroke and heart attack, and those exposed to road traffic and aircraft noises have a higher risk for hypertension. In addition, exposure to noise can lead to reduced reaction time and increased levels of annoyance. Preventing excessive exterior noise from reaching building interiors can help improve occupant comfort and well-being.
  2. Internally Generated Noise (Feature 75): Electronics, HVAC systems, mechanical equipment and other noise-emitting office devices, as well as occupants themselves, can be sources of indoor noise. As offices and workspaces are increasingly designed to promote employee interaction, occupants can experience decreased levels of privacy and acoustic comfort, especially when users with different job types share a space. Office noise can lead to decreased productivity, especially in open-plan offices where aural distractions and interruptions from other employees are frequent. Additionally, studies show that exposure to noise generated within the building can lead to reduced concentration and mental arithmetic performance, and increased distraction due to reduced speech privacy.
  3. Reverberation Time (Feature 78): Reverberation time, or RT60, is a metric that describes the length of time taken for a sound to decay by 60 dB from its original level in a large room. Optimal reverberation times vary depending on room volume, intended use of the space and the frequency of transmitted sound. In spaces with high reverberation times, the sounds of voices and footsteps take longer to dissipate, contributing to higher levels of ambient noise. The noise produced by reverberation can decrease speech intelligibility and, in some situations, cause additional stress. This performance specification can be met by using sound-absorbing materials on various surfaces and design elements.
  4. Sound Masking (Feature 79): Ambient silence can be just as distracting as a loud environment because it highlights acoustical disturbances and decreases speech privacy. Overhearing private conversations is reported as a specific cause of employee acoustic dissatisfaction in open offices. Sound masking systems supply a low level of background noise to provide workers with a degree of speech privacy in their communications and can decrease distraction associated with aural interruptions.
  5. Sound Reducing Surfaces (Feature 80): Proper design and construction are not always enough to achieve acoustic comfort in buildings. Sources that contribute to acoustic dissatisfaction such as sound transmission from internal and external sources, footfall noise and voices from adjacent spaces are difficult to control. However, sound reduction treatments that incorporate absorptive surfaces, such as wall panels, ceiling baffles and surface enhancements can help with reverberation management and improve acoustic comfort. The NRC of a material plays an important role, which we will review in more detail in another section.
  6. Sound Barriers (Feature 81): Noise from adjacent spaces can be disturbing to building occupants. Careful detailing and high quality construction materials can greatly improve the sound reducing abilities of interior partitions or doors that act as sound barriers and reduce sound transmission between adjacent spaces.

The Fitwel system includes more than 55 evidence-based design and operational strategies that enhance buildings by addressing a broad range of health behaviors and risks29. Each strategy is associated with unique point allocations, based on the strength of associated evidence and the demonstrated impact on occupant health. This means that strategies with stronger, multifaceted impacts receive more points.

Fitwel addresses health as an interconnected system, with no single dominant category or area of focus, and as such all strategies are voluntary, with no individual prerequisites. Fitwel addresses seven Health Impact Categories, including:

  1. Impacts Surrounding Community Health
  2. Reduces Morbidity and Absenteeism
  3. Supports Social Equity for Vulnerable Populations
  4. Instills Feelings of Well-Being
  5. Enhances Access to Healthy Foods
  6. Promotes Occupant Safety
  7. Increases Physical Activity

It’s worth noting that Fitwel does not explicitly address occupant comfort in terms of acoustics, and without prerequisites, it’s difficult to determine whether a building certified to the Fitwel standard will be designed with proper acoustic protocols or not. So, which one should architects and designers use to most effectively impact wellness? For the purposes of this CEU, it’s evident that WELL offers a more robust framework to address acoustic comfort, so specifiers should take that fact into consideration.

This is by no means an endorsement for WELL, however; rather, the two building standards simply represent different approaches to designing for wellness. Architecture and design firm Stantec highlights several of the key differences between the two systems this way:

[Fitwel’s “on-the-go” certification] promises a less cumbersome, more user-friendly experience, and it allows for a four to six-week review—much faster than WELL’s Performance Verification. […]

Another significant point of comparison is cost—Fitwel is notably less expensive than WELL or LEED certification. Project registration and certification total a maximum of $7,000. This price point makes Fitwel feasible for projects of all sizes, types, and budgets.

By requiring a minimum, holistic level of compliance for all projects, WELL preconditions set the bar high. But it can also discourage and/or disqualify some projects from seeking health-focused certification. Fitwel eliminates such requirements, welcoming more projects but in a less holistic manner than WELL. […]

Ultimately, Fitwel has 13 unique strategies not encompassed in LEED or WELL, including a section on emergency preparedness. While Fitwell does overlap with 27 WELL features, WELL is far more robust with 63 additional unique features. Fitwel also omits many relevant green practice topics: organizational transparency, comfort (thermal, visual, ergonomic, and acoustic), materials, etc. So, while an accessible standard, one could argue that Fitwel is not stringent enough30.

In summary, architects and designers who wish to address wellness across a broad range of project types without the high costs of certification, long approval times or often cumbersome prerequisites, Fitwel may be the way to go. On the other hand, those particularly concerned with taking a more rigorous approach to health impacts in buildings and mitigating the negative effects of unwanted noise in interiors, WELL may be the better option.

Design for Engagement and Productivity

Engagement has become a kind of buzzword in the corporate world in recent years. Much like productivity or collaboration, companies seem to be aiming for a target that seems either elusive or just difficult to define in the first place. This may be in part because engagement and productivity are interrelated but not always understood.

So, what does employee engagement mean, what does it look like, what impact does it have on the bottom line and what, if anything, can design professionals do to support them? Those are the questions we’ll attempt to answer in this section.

By way of definition, “employee engagement lies at the intersection of maximum contribution for the business and maximum satisfaction for employees,” according to Human Resources Today31. “It’s a sustainable level of high performance that benefits both the company and the employee.” Harvard Business Review offers a simpler definition: “People want to come to work, understand their jobs, and know how their work contributes to the success of the organization32.”

It sounds straightforward enough, but what complicates matters is that employees can be productive without being fully engaged, but their performance won’t be sustainable over time. So, while every organization or business wants productive employees for the long term, it’s important to realize that productivity is only part of the equation—and engagement is actually the key to achieving it. In fact, employees who are engaged are by nature more productive than those that aren’t.

A recent Gallup poll found that work teams who scored in the upper 25% in employee engagement outperformed those in the bottom quarter by 10% on customer ratings, 22% in profitability and 21% in productivity33. The survey also revealed that teams in the top quartile also saw significantly lower turnover (25% in high-turnover organizations, 65% in low-turnover organizations), shrinkage (28%) and absenteeism (37%) and fewer safety incidents (48%), patient safety incidents (41%) and quality defects (41%). Further, employees who are engaged tend to be more innovative, which has a direct impact on the success of the business.

“Companies constantly evolve, and they need new ideas all the time. Engaged employees are a lot closer to the best ideas,” says Jim Harter, Ph.D., Gallup’s chief scientist of employee engagement and well-being. “They’re thinking about the whole company and how they fit into it, and their ideas lead to better decisions.”

However, the vast majority of employees in the workplace (85%) are either not engaged or actively disengaged, according to the State of the Global Workplace report34. While the study noted that only 18% of employees are actively disengaged, the presence of these types of employees in the workplace can have a negative effect on others. Experts define employee disengagement as “a negative, unfulfilling, work-related state of mind that is characterized by … infidelity and disloyalty,” and also “the withdrawing or defending of oneself physically, cognitively or emotionally during work role performance35.”

While disengaged employees present a significant challenge, what’s perhaps even more daunting is the remaining 67% of employees who are described as “not engaged. “This latter group makes up the majority of the workforce—they are not your worst performers, but they are indifferent to your organization,” the authors of the State of the Global Workplace observe. “They give you their time, but not their best effort nor their best ideas. They likely come to work wanting to make a difference—but nobody has ever asked them to use their strengths to make the organization better.”

The costs of actively disengaged employees on companies are substantial and aren’t limited to turnover and recruitment. Gallup found that actively disengaged employees cost the U.S. $450 billion to $550 billion per year, which doesn’t even consider the employees that are described as “not engaged”37. Globally, the economic losses of this workplace phenomenon are estimated at $7 trillion in lost productivity37.

Can Design Improve Engagement?

The design of the workplace has a measurable impact on employees in many ways. For example, data from Gensler’s 2016 U.S. Workplace Survey uncovered a statistical link between the quality and functional makeup of the workplace and the level of innovation employees attribute to their companies38. The study concludes that employees at the most innovative organizations share several common characteristics:

  • They have better-designed workspaces.
  • They leverage the whole office to greater effect.
  • They spend less time at their desks, choosing instead to collaborate and socialize in conference rooms, open meeting areas and café spaces.
  • The spend more time working away from the office—averaging just 74% of the week in the office.
  • They have more choice in where they work.
  • They have greater access to amenities in or near their office locations.

While innovation is distinct from engagement, studies cited earlier note that employees who contribute the best ideas are the ones that are also engaged, which suggests the two are linked. Further, employee wellbeing and happiness also play a role in engagement, which can be supported by the work culture and environment.

One prominent furniture manufacturer explained the interrelationship between employees, wellness, engagement and the workplace in a white paper this way: “You can’t be happy if you don’t feel well and you can’t be engaged if you’re too stressed out. The good news is that employers have just as much to gain from a productivity and innovation standpoint by positively addressing these factors with their employees. By fostering a work culture and designing an office environment that values the whole person, organizations can reap the numerous benefits of having healthy and happy employees who are engaged in their work39.”

A well-designed office alone can’t guarantee employee engagement, but it can foster it in tandem with a positive culture. Organizations can utilize physical space to help foster an environment of engagement by:

  • Creating environments that encourage collaboration. Companies that hope to boost employee productivity and engagement should ensure their offices are designed around their company values40. In other words, if collaboration is important to the organization, the workplace needs to offer ample space and technology for employees to work together, whether it’s more conference rooms, lounge areas or casual touchdown spaces that invite coworkers to spend more time face to face. Conversely, if a company requires employees to perform a great deal of focused work, spaces that offer a higher degree of privacy need to be made available. Regardless of the tasks, employees should be given the right tools for the job in the form of physical space if they hope to be productive and, ideally, engaged.
  • Offering spaces that support interpersonal relationships. Research demonstrates that 72% of adults report feeling lonely, so providing employees with time and space where they can build interpersonal relationships can support engagement41. “No one wants to simply go to work and clock in and clock out, day after day, without a human connection. So, to make sure that your employees enjoy coming to work, be sure to check on teams and find out if they’re able to find space in the workplace where they can share a meal, conduct a meeting or just collaborate,” suggests a Forbes article.

Additionally, there are several other strategies organizations can take to create a culture and a workplace that supports engagement, including: making employees feel like they’re part of a team/family and connected to the organization’s purpose; providing spaces, amenities and events designed to encourage team building and random moments of fun; promoting employee autonomy through less micro-managing, by allowing personalized workspaces and offering a choice of workspace settings; supporting flexible working arrangements that allow employees to achieve work/life balance; offering more frequent feedback in the form of coaching sessions; and allowing time for personal development and encouraging breaks.

What Role Does Acoustics Play in the Process?

It might seem like a stretch to link good acoustics with employee engagement, but the lack of acoustics might be a detriment to keeping engaged workers on task. If noise is an impediment and an annoyance in the workplace—and it is, based on data presented earlier in this article—then it stands to reason that even if a company’s culture promotes engagement and the space is well-designed otherwise, poor acoustics can still hinder even the best employees for performing at their best.

In a 2014 IIDA workplace survey, 80% of respondents noted that “constant interruption” was the one thing they would most like to change about their workplace because it leads to fatigue or burnout.  In fact, one study that focused on the startle reflex revealed that burned-out participants had a dramatically stronger response to startling noise compared to a control group, suggesting that acoustical control in workplace settings could potentially help support burned-out employees43. Design strategies to deal with behavioral coping may include the presence of alternative spaces for quiet work or reflection44.

“High work demands are often more tolerable when employees feel they have control over their work and work environment,” according to the WELL Building Institute45. “Many factors may impact feelings of control over the physical work environment—ranging from lighting to privacy to psychoacoustics.” In other words, workplace design and policy strategies can be used not only to help prevent burnout among workers but also support productivity, happiness and possibly engagement as well. 

Material Considerations

Acoustics is tied inexorably to materials. Sound that travels through a space and reflects off hard surfaces results in echoes and reverberation, which leads to noise, fatigue, unintelligibility and poor-sounding spaces overall. That’s not to say hard surfaces should be avoided altogether. In fact, all materials absorb sound, but in varying degrees. For example, materials with a rigid and compact structure, such as concrete and glass absorb much less than, say, carpet or textiles that feature looser construction and fibers that absorb more than some harder materials.

Therefore, using proper acoustic principles and materials together can be used to absorb, block, cover and dissipate the right amount of sounds in the right ways. As such, careful consideration should be given to the types of materials specified within an environment—be it the workplace, schools, hospitals, courtrooms or other public spaces—and how well they perform from an acoustical perspective.

Materials specified in a project are typically assigned either an NRC or STC rating, so let’s take a look at what those mean and how some of the more common building products stack up:

  • Noise Reduction Coefficient (NRC). NRC is a single number rating indicating the level of sound absorption provided by the product being tested, with a maximum value of 1. NRC is suseptible to many variables during testing, so the American Society for Testing and Materials (ASTM) has standardized testing procedures to measure NRC including frequencies from 100 Hz to 5000 Hz, and is expressed as the average of absorption coefficients at only four frequency bands: 250, 500, 1000 and 2000 Hz. (Note: Normal human hearing range is from 20 Hz to 20,000 Hz.) Products that absorb frequencies evenly across all bands are generally more effective at controlling sound than those that do not. The NRC rating is most used for ceiling tiles and other wall or ceiling-mounted acoustical absorbers, as well as freestanding dividers and partitions. Also, new and innovative acoustic textiles help provide uniform absorption at all frequencies. Depending on the material and installation, these innovative textiles can reach class A for sound absorption.
  • STC: The key difference between NRC and STC is that NRC is used to rate materials that absorb sound, while STC is used to rate materials that block sound. STC is a unit of measure of how much airborne sound energy is attenuated across a boundary wall, ceiling, floor, door or other partition. It is mostly used for interior spaces but there are test procedures for exterior uses as well. While measured in decibels, a sound transmission class rating is expressed in STC with a maximum value of 70. For example, if a wall isolates 42 dB between two adjoining spaces, it is said to be rated for 42 STC, not 42 dB. Standardized testing is performed on frequencies from 125 Hz to 4,000 Hz. 

The NRC ratings of different materials vary widely, depending on the type of product, structure, density and even the manufacturer. Below is a list of commonly used building materials and the average NRC rating for each:

  • Acoustic panel (1”) = .80 – .95
  • Acoustic panel (2”) = .95 – 1.0
  • Carpet = .35
  • Concrete = .35 – .7
  • Drywall = .05
  • Fiberglass = .75
  • Gypsum =.06
  • Mineral Fiber Ceiling Tile = Up to .7
  • Plywood = .23
  • Regular glass = .02
  • Steel = .1
  • Wood = .15

According to the Whole Building Design Guide (WBDG), the types of materials and acoustic treatments design professionals should employ vary between open and closed offices. In other words, a one-size-fits-all approach will most likely not result in the desired noise control measures if deployed incorrectly. Below is a chart from the WBDG that illustrates the types of products and strategies that should be used in various settings based on the activities taking place in them:

As a general rule, designers should pay close attention to NRC and STC values and specify materials that will adequately absorb or block noise from interior environments. If specifying hard surfaces that reflect sound, absorptive materials are an absolute must and should be considered along with sound masking systems.


As this CEU has demonstrated, acoustics plays a vital role in the design of healthy and effective interior environments—spaces that facilitate learning, healing and working at their best. It should be restated, however, that the field of acoustics is complex and requires a thorough understanding of the relationship between sound and architecture to address noise effectively.

Further, each space is unique and requires a tailored approach to sound mitigation. We recommend that design practitioners’ partner with acousticians and manufacturers to address the complexities presented in their projects to deploy acoustic strategies and treatments effectively.

By doing so, architects and designers can help ensure they are creating spaces that support the sound of wellbeing, engagement and productivity.

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