Creating Comfortable Environments with Acoustics

While most acoustical design components integrated into the overall design of a building are not easily seen, poor acoustics rarely go unnoticed.

“Acoustic design is important for occupant comfort, and for a space to perform as intended,” said Andrew Parise, Eastern Region acoustics lead for WSP USA. “During the design of a project, WSP anticipates potential acoustical issues and develops appropriate solutions based on the project needs.”

“Every project is different—construction, location, limitations, budget—and what worked well for one project may not be a viable solution for another,” added Kristina Sells, Western Region acoustics lead for WSP USA. “Our team works hard to provide detailed recommendations and to develop creative solutions that are specific to each project.”

Four key factors affect the overall acoustic design of a building:

• Interior Sound Isolation – reducing noise transmission between interior spaces to provide appropriate degrees of noise control and/or privacy.
• Exterior Sound Isolation – reducing noise ingress from exterior noise sources into the building.
• Interior Room Acoustics – designing a space to have appropriate levels of sound absorption (soaking up sound), sound reflection (sound reflecting off hard surfaces back into the room), and/or diffusion (scattering of reflected sound).
• Background Noise – controlling airborne and structure-borne noise from mechanical-electrical-plumbing (MEP) systems inside the building, as well as noise projected out to the surrounding property and property lines.

With 150 acousticians around the world and numerous disciplines under one roof, WSP can identify project requirements and provide input to the design team that factor in the specific needs of a project from an architectural; interior design; mechanical-electrical-plumbing (MEP); structural engineering, audiovisual and technology systems, and building enclosures perspective.

“We can communicate efficiently as a team, get our acoustic concepts and recommendations into the design of those systems earlier for budgeting purposes and avoid a lot of rework in the design of those systems that sometimes happens with a separate acoustic consultant,” Parise said. “The end result is not only a more efficient design process, but also a fully coordinated design that, once built, works for the end users not only in terms of the acoustics of the space, but in all aspects of how they operate.”

Successful acoustic design makes it possible to achieve privacy between adjacent hotel rooms, residences or offices; keep occupant noise to a minimum in an open office, restaurant or event space; reduce annoying and potentially harmful noise sources such as pumps, transformers, generators and HVAC equipment; provide an environment where a public-address system can be clear and intelligible; or any number of other applications.

“Improved recovery has been linked to a patient’s comfort, employees and students will be more productive and effective while working in an acoustically comfortable environment, and the overall enjoyment of a space can hinge on whether the acoustics were considered,” Sells said. “There is a growing understanding from architects and developers that acoustics play a vital role in a successful project.”

As one of the largest acoustic consultancies in the world, WSP is currently working on acoustic design projects across the U.S., including commercial and office buildings, health care facilities, hotels, hospitals, laboratories, airport terminals, educational facilities and civic centers. Current projects include:

Located in Pittsburgh, the facility is concerned with meeting appropriate guidelines for patient comfort. The design prepared by WSP includes an evaluation of expected exterior noise intrusion into patient rooms from a rooftop helipad, sound isolation/privacy, HVAC noise and vibration control, and interior room acoustics.

“Patients need to be able to relax and be comfortable in their rooms while recovering,” Sells said. “That is much harder to do when you have noisy mechanical equipment supplying air to rooms, or if you can hear every word that is said in the room next to you or at the nurse’s station at the end of the hall. Designing for a comfortable acoustic environment removes one element that can create stress from an already stressful situation for a patient.”

In addition to comfort, privacy is also a very important aspect of the acoustic design on health care projects, since there are national standards to protect individuals’ medical records and other personal health information.

A client in San Francisco was seeking tenant interiors for a new office building that provides a dynamic acoustical environment, which achieves privacy, intelligibility and comfort throughout the office spaces. Acoustical engineering services focused on interdisciplinary design practices from an early stage on the tenant floors of the project. Final phases of the project are currently in design, although most of the building is currently under construction.

Sometimes, quiet is not necessarily the goal in an open office environment.

“The biggest challenge here is providing an open, collaborative environment, while also providing a space where occupants aren’t annoyed by their neighbors and can have a reasonable expectation for privacy,” Parise said. “Open offices can sometimes be too quiet – meaning you will be able to hear and understand every word your coworkers say, and every click of the keyboard or mouse.”

One common approach is to design the HVAC system to be a little louder than it would be for a private office or conference room, adding sound masking—which involves playing a pleasant noise spectrum through ceiling speakers—when needed, and incorporating finishes that absorb some of the occupant noise so that it doesn’t travel too far.

Since occupants will always be able to hear coworkers sitting next to them, private phone rooms or conference rooms are also included in the design plan so they can take a private call, or have a meeting away from those doing work at their desks.

The acoustical team coordinated with building envelope, interior and MEP designers for the San Francisco International Airport Terminal 1 project.

All disciplines are working together to create innovative acoustical solutions to reduce exterior noise ingress through the building façade, minimize HVAC noise and vibration transmissions to interior noise sensitive spaces, and create acoustically enjoyable spaces for the patrons as well as the facility employees.

The most comprehensive and cost-effective approach to optimal acoustic performance in a building is to involve acoustic engineers early in a project’s development.

“Sometimes the biggest challenge is when we are brought into a project during later design phases, after programming is complete and the room layouts are set,” Parise said. “We might encounter noise sensitive rooms next to mechanical rooms or spaces with a lot of activity, and we have to find solutions to limit the noise transmitted between spaces.”

He recalled two of his more challenging projects involved residences sharing a wall with a rock concert venue, and a rooftop basketball court above a conference room.

“In both cases, we had to come up with some creative solutions for structural isolation,” Parise said. “If we had been involved earlier in the projects we could have advised on moving some of the room locations and avoided some of the cost associated with the solutions.”

When engaged early, WSP can coordinate with the architect-engineer design team to identify potential cost impacts related to acoustics, and to avoid design decisions that can negatively impact the acoustics of a space. Our design process is typically to summarize coordination efforts and recommendations into formal reports throughout the design.

“We rely on the architects and engineers to incorporate our recommendations into their designs, so collaboration is the most important aspect of how we do business, and how our designs come to fruition,” Sells said.

Looking to the future, WSP is in the early stages of researching and developing the use of virtual reality (VR) and augmented reality (AR) systems to provide a way for clients to hear what a space will sound like before it is built.

“VR and AR will be incredibly valuable tools to help clients make informed design decisions,” Parise said. “Auralizations have been used in the past for this purpose, but where those typically rely on speakers in a room in a specific location, this is intended to be a self-contained system that is portable and can be used in a meeting with clients.”

Acoustics is somewhat subjective, and what is acceptable to one client may not be acceptable to another. For example, law firms require a high degree of privacy between offices, whereas a tech company is typically more focused on an open environment.

“Each client is different, and what is important to one may not be important to another,” Parise said. “We try to provide various design options, and identify what the acoustic impact would be if each were selected to make sure our clients make informed decisions, based on what is important for their needs.”

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