Can You Hear Me Now?

Of course, when we consider the indoor environmental quality (IEQ) factors that influence human health and comfort, indoor air quality (IAQ) probably comes first to mind, followed by thermal and visual comfort. Numerous studies have quantified the value of clean air, good ventilation, temperature control, daylighting, and lighting quality. The sense we don’t hear mentioned as frequently in these considerations is our auditory perception, but acoustic quality and comfort has a significant impact on our performance, stress level and wellness.

Why does acoustic comfort and performance get such limited attention? Perhaps because it is less understood and because its relationship to other aspects of sustainability is tenuous. Ventilation, temperature and lighting all have direct links to energy using equipment and energy performance. The only such links we might make for auditory comfort are that energy efficient mechanical equipment usually generates quieter sound levels and that high-performance windows may limit exterior sound transmission. LEED first introduced an acoustic comfort credit in the 2009 version, and even now, acoustics is limited to one prerequisite (applicable only to schools) and a credit worth one point. Acoustics does occupy a more prominent place in the WELL Building standard in the Sound Concept area, with one precondition and up to 18 points available.

This diminutive status in sustainable building standards does not mean that acoustics is not important. As with lighting, optimized acoustic conditions are critical to improving human performance and supporting health and wellness in buildings, from workplaces, to learning environments, to healthcare and beyond. To illustrate the value, here are several examples of how poor acoustics hamper human performance.

Workplaces

People accustomed to working in office buildings prior to the pandemic can easily relate to the converse of improved human performance; poor acoustics made offices difficult to tolerate, especially for introverts. These poor acoustic conditions emenate from high-density, open plan workspaces where distractions from colleagues result in a lack of concentration and productivity. Or the office may be impacted by noisy mechanical systems, whose droning and throbbing adds more challenges to concentrating on tasks and meeting deadlines. A 2019 study by the Remark Group revealed that 65% of respondents found that noise impacted their accurate and timely performance of tasks, 44% felt that noise negatively impacted their wellbeing, and 40% reported increased stress levels. After an interruption, it takes at least 15 minutes to refocus on a task, so with multiple acoustic interruptions each day in a noisy office, the productivity loses add up.

Learning Environments

In schools, students struggle to clearly hear their instructors in poorly designed classrooms. In these spaces, the room’s acoustics cause speech to be unintelligible even for students learning in their native language (let alone students learning a second language or who have hearing impairments). The Acoustic Society of America determined that excessive noise and reverberation results in up to 25% of information being missed by students in classrooms. And for teachers and instructors, the impact of poor acoustics results in loud classrooms, which create daily stress and strain on the instructors’ vocal cords.

Healing Spaces

Health care environments suffer from noisy conditions that prevent patients from resting and recovering quickly, resulting in higher costs for hospital stays. The World Health Organization (WHO) recommends sound levels no greater than 30 dB in patient rooms, but numerous studies have found mean maximum sound levels in hospitals of 69 dB, with peaks as high as 80 to 100 dB (as loud as a chainsaw). Healthcare staff operating in poor acoustic conditions have difficulties communicating clearly, and in turn leads to medical errors, further increasing costs and impeding patient outcomes.

In all indoor environments, occupants exposed to these poor acoustic conditions suffer from greater absenteeism, which directly impacts productivity in offices, learning success in schools, and patient outcomes in health care environments.

Making the case for measures to mitigate poor acoustics, many studies have shown that optimized acoustic conditions can greatly enhance the wellbeing and performance of occupants within these and other building types:

• Offices with superior acoustics help individuals to be more productive with focused tasks, while also enhancing collaboration in groups that benefit from the shared knowledge.
• Classrooms with proper acoustic design support learning by all students, increasing their ability to hear instruction, gain new insights, and share their knowledge with each other.
• Health care environments designed for acoustic comfort can help staff work more effectively together and reduce errors, and shorten patient stays with improved outcomes, while reducing overall medical system costs.

It is for these and many other reasons that acoustics should be prioritized in creating and maintaining sustainable, high-performance buildings. Optimized acoustic conditions help buildings to perform as they were intended for the programs they support. It is the buildings that serve their purpose, and that people like to be in, that are maintained over time, thus being truly sustainable. Similar to good lighting, quality acoustics is a foundational aspect of IEQ and sustainability, focused on providing supportive environments for occupants, so they can be well and perform at their best.

Watch for future issues, where we will take a deeper dive into design for optimized acoustics, including exterior sound intrusion, sound isolation and privacy, noise and vibration control for building systems, and the selection of acoustic finishes. These topics will identify how acoustics helps improve human performance and supports sustainable objectives, making our buildings more valuable.

Alan Scott, FAIA, LEED Fellow, LEED AP BD+C, O+M, WELL AP, CEM, is an architect with over 30 years of experience in sustainable building design. He is a senior consultant with Intertek Building Science Solutions in Portland, Ore. Jeffery Fullerton, INCE Bd. Cert., LEED AP BD+C, is an acoustical consultant with 26 years of experience and a department manager with Intertek Building Science Solutions in Boston. To learn more, follow Scott on Twitter @alanscott_faia.