Tuning in on sound: Reducing noise in the workplace

By Jeff Fullerton

Noise pollution is all around us. Even when people are inside, it is hard to block out intruding and distracting noises within the space people are in; noise coming from adjacent rooms, areas above or below, or from hallways; or even from outside the building. Conversations or activity of other occupants, the whirl and beeps of computers and electronic equipment, and the hum of HVAC and mechanical systems all create a cacophony of unwanted sound that is hard to ignore.

Designing an acoustically controlled occupied space is a balancing act, as there are many ways to find the best solution for the intended program of the space. Often, the primary goal for a workspace is to create a comfortable and productive space with minimal noise distractions. While most companies prefer the lower cost of an open workspace environment, there is a need for smaller designated areas for very different, specific tasks. The ideal workspace allows for people to have private conversations that might be audible, but not intelligible, or the ability to hear a person talking in larger settings while ensuring there are suitable “quiet” areas where people can concentrate on their tasks. This can also be achieved by integrating appropriate acoustical products with architectural design elements.

Whether building a new space, or renovating an existing one, sound absorbing and/or diffusing finishes involve the right acoustical products, the correct use of these products, key architectural elements, and the expertise of an acoustic consultant (a.k.a. acoustician).

Impact on occupants

One of the first concerns of noise pollution is its effect on human comfort and cognitive performance. Interpersonal communication—hearing and comprehending the spoken word—is difficult when the background sound levels reach 50-60 decibels,¹ for example in a bustling office space, full classroom, or from a loud, poorly designed mechanical system. Whether office space or a classroom, noise pollution can cause distraction, taking attention away from the task or lesson at hand and the important concepts being communicated. In turn, a distracted employee battling a noisy environment is less productive; a distracted student in a similar setting has trouble retaining new information, and patients with sleep disruption in a hospital can require longer recovery times. And it is important to understand these conditions do not consider hearing disabilities or people for whom English is a second language; both conditions can make understanding speech even more challenging and problematic to follow.

Noise pollution can cause occupants to feel stressed or fatigued due to the extra effort required to stay tuned in. Blocking out surrounding conversations and activity noise takes mental effort. Alternatively, healthcare providers can experience “alarm fatigue” from being exposed to the multitude of medical devices, all contributing their own noise to the cacophony within the healthcare environments. Over the course of a day, these conditions can be exhausting.

Interpersonal communication is affected as well. Multiple side conversations and background noise can make it difficult to clearly hear and understand a primary talker or teacher. Unintelligible language can lead to misunderstandings, miscommunication, miscues in collaborations, and mistakes.

Lastly, noise pollution can lead to physical ailments and mental duress. Prolonged exposure to high and sustained levels of noise can negatively impact health, including increased risk of headaches, hearing loss, high blood pressure, and cardiovascular disease.^2,3 Simultaneously, persistent discomfort of an unpleasant environment can cause decreased morale and job satisfaction or poor academic performance.

Situational pain points

No matter the building type—office, educational, healthcare—noise control problems are similar across the board for most building projects. There are specific areas of concern depending on the environment. The purpose of the building determines what types of noise pollution creates “pain points” for occupants. Once these are defined, acoustic consultants can work toward effective solutions.

Office space

Controlling noise levels to establish a comfortable and productive working environment.

This goal includes conditions that support collaboration or focused independent activities.

Office space pain points include conversations or activity of other occupants plus the background sounds of computers, office equipment, and mechanical systems. Multi-functional activities occur in open office space, so the acoustics plan must include a variety of solutions to create a comfortable setting to complete tasks and assignments, hold private conference calls, meetings, work with freedom from distraction.

Classrooms

Creating a distraction-free environment conducive to learning and retention of studies, while ensuring clarity for communication and effective listening.

Whether in K-12 or higher education institutions, acoustic pain points in educational facilities revolve around the ability to clearly hear the instructor and to contain noise levels so students can remain focused and on task. Most classrooms are built with drywall, tile floors, and ceilings made with acoustical ceiling tiles to provide some sound absorption in the space; however, they lack any soft surfaces such as curtains or upholstered furniture, the acoustic consultant can help build a better learning environment with sound-absorbing ceiling panels, ensuring students have a better chance of retention.

Healthcare facilities

Soundproofing for privacy and patient recovery is crucial. Maintaining privacy in a calm, reassuring environment is essential for hospitals. Most healthcare facilities have exam rooms lined up next to one another. Due to this design plan, it is essential to ensure conversations remain private. While hospitals are intended to provide patients with a quiet and restful environment to recover and recuperate, they are unfortunately also hotbeds of noisy activity. A strategic acoustic plan can aid in patient recovery by limiting activity noises from adjoining rooms, visitors, or staff in the halls, as well as rolling medical, food, or utility carts.

Hotels, dormitories, and multi-family residences

Reducing activity noise and providing vibration control in common areas, while creating sound barriers for privacy between guestrooms, living, and sleeping spaces.

Hotels, school dormitories, apartments, and condos have the same design element in common—shared walls and floor/ceilings. To isolate noise between separate living quarters and ensure occupants’ peace and quiet, a variety of enhanced sound isolation products can address these pain points. Additionally, acousticians and architects must be cognizant of exterior noise and vibration due to locations close to transportation hubs, highways, airports, and city living.

Options for acoustic solutions

Most buildings start with the same basic architectural elements—four boundary walls, concrete or hard surface flooring, and high ceilings. Commercial, institutional, and educational spaces often have oversized windows for natural lighting, suspended ceiling lights, exposed ductwork, and utilitarian furnishings designed for more practical purposes rather than style. All this contributes to elevated noise levels.

Fortunately, there is a wide variety of acoustical materials and products available to help alleviate the noise and create an acoustic balance in any type of space. Some products are designed to reduce the transmission of sound from one area to another while other products or materials help to absorb sound in specific areas.

The design team relies on a mix of products to accomplish acoustic goals set by the architect or building owner. For heavily occupied spaces such as commercial offices or classrooms, where sound reverberates or bounces off hard surfaces, architectural and design elements, such as acoustic ceiling tiles or carpeting, help absorb noise from within the room while heavy drapes or curtains cushion sound waves bouncing off windows.

Time-tested tools of the trade are sound-absorbing panels, which can be attached to walls and ceilings. Acoustic panels have a sound-absorbing core, such as foam or fiberglass, covered in fabric to absorb sound waves and lessen room echoes. Similarly, acoustic banners and baffles, which are hung from the ceiling, absorb noise and mitigate excess sound reflections. These types of products can range from standard-sized, fabric covered acoustic panels to custom-cut shapes with imprinted designs to custom-manufactured wall and ceiling panels that function beyond sound control to provide a desired aesthetic to the space.

On the other hand, airborne and impact sound isolating products often go unseen but offer excellent sound control advantages. Architects can work with acousticians to include sound-absorbing insulation to reduce sound transmission through walls, floors, and ceilings. Sealants can be used around windows and doors to seal gaps and prevent sound leakage. Impact insulating underlayments on floors can reduce structure-borne noises such as foot traffic, rolling carts or equipment, and furniture movement.

Sound masking

It is not uncommon for architectural solutions and privacy concerns to face practical or financial constraints, which can result in falling short of the acoustical goals. When this occurs, sound masking is an audio technique that can improve a crowded space’s acoustic environment. This technique works by introducing a broad-spectrum noise consisting of specific frequencies or levels that make certain sounds less noticeable. The masking sound is engineered to cover the frequencies of human speech without being intrusive or recognizable; the goal is the sound is very similar to the sound of a waterfall or airflow sounds from a fan.

Similar to how prerecorded music has been used to create a pleasant noise distraction or ambiance in retail and grocery stores, or how sound masking systems make continuous soothing sounds to lull people to sleep, sound masking involves low-level background noise to mask or cover the typical noise distractions of an open space environment. Modern day acoustics involves finding a balance between architectural noise reduction and increasing the background sound. Sound masking offers a counterbalance to conversations, computers, office equipment, and mechanical systems while affording occupants privacy for phone or personal conversations, as well as requiring less mental effort to block out noise.

Sound masking systems are often used in open workspaces, private offices, and healthcare facilities. They can be customized to meet specific acoustic requirements set by the building owner and integrated into the architect’s design from the beginning or installed later as a standalone system within open office spaces and circulation areas.

Building a better building envelope

Achieving the well-balanced acoustic goal becomes challenging due to improvements in building envelopes, constructing demising assemblies for enhanced sound isolation, and quieter mechanical systems.

A building’s exterior envelope controls interior noise primarily by blocking out disturbances. As with thermal concerns, the envelope is the barrier between outside and in; thus, material selection weighs heavily on how well noise pollution remains outside. Selecting materials with high sound insulation properties is the key. For exterior walls, heavy, dense materials such as concrete, masonry, and gypsum board can effectively block out noise better than lighter-weight materials.

Likewise, highly insulated wall assemblies can often provide both thermal and acoustical isolation benefits. Double- or triple-paned glass windows offer acoustic properties single-pane windows cannot provide. Solid airtight doors provide better privacy than hollow core doors. Using sealants to fill the gaps around windows, doors, and joints ensures an airtight fit that prevents noise from filtering in from the facade. However, it is important to understand while foam insulations provide excellent thermal insulation, they have very limited benefit for sound insulation and should be avoided for projects in loud areas. These value-added elements should be considered in the pre-planning and early design stages of building.

The construction of such architectural components as party or separation walls, known as demising assemblies, are used for enhanced sound isolation in multi-unit buildings, such as hotels, apartments, and dormitories. They help maintain privacy and restrict noise coming from other units by lessening airborne, structure-borne, or vibration transmissions from adjacent spaces.

Finally, even with all the references to the sounds of “running of mechanical systems,” design of HVAC, ductwork and venting, plumbing, and vertical transportation are always improving to operate more efficiently and quietly, thus lowering interior noise pollution. When building a better building, expense, efficiency, and acoustics are key considerations for a quiet operating facility.

The upside of a better building envelope is a quieter interior environment; the downside is the interior silence can allow other noises within the building to be perceived as more noticeable. Without the innocuous intrusion of exterior sounds, people are relatively impacted by other interior noises, which may cause stress. For example, creating a space that is too quiet can stress occupants. A space so quiet that one can hear a pin drop is often a space where the neighbor’s activities can be clearly heard, which is not desirable. Such conditions would allow the occupants to hear, even tune in more, to the noises around them. In turn, they become distracted and lose their ability to focus or concentrate on their work. The key to achieving balance is selecting the right components for the demising assembly that will improve the occupant condition.

A sound design plan

Achieving architectural acoustic excellence requires a sound design plan. This involves, first understanding how the space will be used and second, what types of noise pollution will need to be considered. While the acoustics plan for a busy office or a classroom versus a hospital recovery room, hotel room, or residence are similar, they do require their own unique mix of acoustical materials and devices. This is where an acoustic consultant can be of assistance.

Acoustic consultants specialize in evaluating and exploring sound management of buildings or specific areas within or around buildings. Architects, designers, builders, property owners, and facility managers rely on the expertise of acoustic consultants to mitigate noise pollution in different environments. Much of their recommendations will ensure noise pollution pain points are addressed with solutions that meet specific acoustic requirements and standards.

Acoustic expertise

Acoustic consultant services benefit multiple sectors of the build industry—from the architecture, design, and construction of buildings to major complex developments such as airports, transportation hubs, entertainment venues, shopping and dining districts, multi-residential buildings, sports arenas, and industrial sites.

Aside from testing and analyzing sound isolation systems for various building types, acoustic consultant services include assessing noise pollution, optimizing performance acoustics, and determining the noise impact of sports, manufacturing, or commercial/industrial development on surrounding communities, including wildlife.

Here is an overview of available acoustic consultant services:

• Perform noise surveys and measurements to assess current acoustic conditions.
• Identify existing or proposed sources of noise and offer suggestions for effective mitigation.
• Develop a strategic and detailed plan to control noise and/or improve overall acoustics.
• Advise architects, engineers, and building owners on how to incorporate acoustic solutions into the building design.
• Offer insight on acoustic materials and devices, as well as advise on material finish selections.
• Review post-construction installations for compliance and performance objectives.
• Provide expert testimony and comprehensive technical support in legal proceedings.

Involving an acoustic consultant

Acoustic consultants have an important role in helping architects and designers create comfortable, functional, and aesthetically pleasing environments by controlling noise and enhancing sound quality.

An acoustician’s services can be called in at any stage of a project; however, early identification of potential noise sources and implementation of acoustical solutions can mitigate or prevent noise pollution in the final project in a more cost-effective manner than addressing these concerns late in a project’s design or during construction. Here are some of the proactive services an acoustic consultation can provide a new build or renovation project:

Project design review

An acoustic consultant can review site conditions, identify potential areas of concern whether from interior or exterior sources, use calibrated equipment to perform acoustic and vibration analyses, and provide an outline of acoustic goals and requirements for the project. This service can help architects and designers understand how the environment they are building in or around will affect their project, or how their project will impact the surrounding environment.

Key areas of consideration when developing an acoustic plan include:

• The volume of the space, measuring the room’s width and length, as well as its ceiling height. Larger volume spaces tend to result in longer reverberation times and can become “noisy.”

• The surface finish of design elements such as walls, flooring, window size, and coverings. Too many reflecting surfaces can result in noisy spaces where speech is difficult to understand.
• The types of furnishings such as cubicle walls, upholstered furniture, and table-top surfaces.
• The purpose of the space, whether a row of cubicles or a private conference room in a commercial setting; a classroom, music room, gymnasium, or cafeteria of an educational building; private sleeping of a dormitory or living quarters of multi-unit residences.
• The current problems, particularly when the project involves a renovation.
• The day-to-day noises associated with the space—occupants, mechanical systems, adjacent rooms, excessive reverberation, echoing, unintelligible public address (PA) system, exterior noise.
• The achievement of acoustical goals—an office space that allows for quiet conversations and focused work; a teacher being heard in a classroom; an audible PA system in a crowded gymnasium; clear speech in an auditorium; and so on. 

Site selection review

This service is especially helpful to a project if more than one site is under consideration. Each location can be reviewed for potential noise concerns, helping to determine the final site selection of the project. Several factors determine a building site’s final site selection, including:  1) how the building will be oriented to surroundings—i.e. facing away or setting back from a busy street; 2) environmental noise and vibration of outside proximity to airports, or construction, that might impact exterior areas or interior spaces; 3) environmental noise and vibration of underground sources, such as subways, railways, and highways; and 4) capability of sound and vibration isolation treatments to reduce airborne, structure-borne, and vibration transmission into interior spaces.

Design conception

The acoustic consultant works directly with architects and engineers to develop acoustic strategies suitable for how the building will be used—e.g. commercial office, school classroom, healthcare exam rooms, and so on. This service includes advising on building orientation, design layout, building materials selection, as well as addressing noise-specific concerns of room dimensions, overhead lighting, ductwork, mechanical systems, and windows. The acoustic consultant can interpret product data to ensure the performance is applicable and appropriate for the use of the product for the project goals.

Acoustic and vibration modeling

Using specialized software and computer modeling tools, acoustic consultants can analyze and visualize predicted acoustic and vibration conditions of a project. Detailed model simulations can predict interior and exterior sound propagation, assess reverberation levels, and help create ideal room layouts, including acoustic finishes and placement of acoustical products to optimize noise control. Vibration modeling helps determine whether vibrations will be felt within the building as well as predict vibrations as ground-borne or structure-borne noise. Vibration modeling can also identify potential issues for sensitive equipment, such as electron microscopes, MRI, or nano-fabrication equipment, particularly when there are vibration sources nearby.

Audio simulations (auralizations)

Auralizations can allow a project team to hear what the design of a space would sound like and understand how different options might sound for the future occupants. Auralizations help building owners, designers, and other decision-makers select design options, and potentially save the expense of post-construction modifications. Auralizations allow
listeners to experience the effectiveness of sound-absorbing finishes and room shaping, ensuring their spaces achieve the desired acoustics—such as clear and understandable speech, a quiet working environment, or ideal acoustical settings for musical performances.

Auralizations can also be used to hear other acoustic conditions such as the isolation or transmission of sound into spaces from exterior or interior sources. This type of auralization demonstrates how recommended isolation treatments will help achieve project acoustic goals.

Regulatory compliance

Local building codes, noise ordinances for acceptable noise levels, and LEED certification requirements all influence the design and the selection of building materials. An acoustic consultant can help ensure compliance in meeting requirements and obtaining necessary permits or approvals from regulatory authorities.

Construction

Acoustic consultants can perform quality inspections throughout the construction process, ensuring that acoustical products are installed properly and function as intended.
From jobsite inspections to quality assurance testing, acoustic consultants can provide guidance to contractors and subcontractors working on installation. If adjustments are necessary, it is much easier to do in progress rather than as
a do-over.

Acoustic commissioning

Peer review of existing, renovation or new construction projects can ensure the facility achieves the Owners Project Requirements (OPR), LEED Certification credits, WELL Sound Features, or other project objectives. The acoustic consultant can provide documentation showing the final design is consistent with the stated acoustic performance objectives.

Post-construction evaluation

Acoustic consultants can perform final acoustic tests and measurements to verify installations work appropriately, and all performance objectives have been met. For instances where acoustic panels were value-engineered out of the original design and the completed space is too loud, the acoustic consultant can help select acoustic products to provide noise control.

Expert witness services

Acoustic consultants can be called upon to present testimony and opinions allowing complex technical issues to be understood by laypeople. These instances may involve acoustical complaints with residential projects, corporate facilities, higher education facilities, industrial complexes, community noise and vibration conditions, and accident investigations. It is important to have an acoustic expert who can help clarify and determine the factors contributing to the litigation.

Product testing standards

Mounting concern regarding how sound impacts human health, cognitive abilities, and performance has led to increased regulation for accurate testing, which is essential for documenting the acoustical performance of building products, materials, and devices.

An acoustic consultant can supply documentation and valid data to confirm compliance of acoustical products, materials, and devices. This is accomplished through a variety of testing methods and services:

• Laboratory testing—where the test conditions are carefully controlled for comparison with other products.
• Field testing—where the acoustician can assess the design and installation of acoustic materials and products onsite to confirm whether project goals and performance levels are met.

• Data source—acousticians can provide valid data regarding the advantages of different acoustical products, test study results, and more to architects, facility owners, property managers, inspection and building authorities.
• LEED certification—the adoption of the LEED codes by healthcare and educational institutions and the creation of green construction codes for all types of buildings has pushed acoustical performance to the forefront of desired building traits. An acoustical consultant can provide reliable testing and data support to help client’s meet certification levels.

Acoustic tests

There are various ratings for quantifying the airborne insulation performance of products and assemblies. Two areas of focus are airborne sound transmission loss (TL) and impact sound transmission.

The key to improving airborne sound TL is to find the sound and determine the appropriate solution. The acoustic consultant can gauge how the building product or system will isolate noise from one area to an adjacent area, such as from two rooms inside a building or from the building exterior to the building interior.

Sound TL is a measurement of how much airborne sound is blocked by a building partition. The TL of a partition is measured by generating broad band noise in one room, then measuring the sound pressure levels (SPLs) in both that room and the adjacent room.

Sound Transmission Class (STC) is a single number rating used to evaluate the performance of many building elements in a laboratory. These elements include floor/ceiling assemblies, doors, walls, windows, curtain walls, skylights, louvers, roof systems, etc. This rating can also be used for exterior facades and facade elements.

Outdoor/Indoor Transmission Class (OITC) is a single number rating used to evaluate the noise isolation of exterior walls and facade elements exposed to transportation and other low frequency noise sources in a laboratory. This rating uses a reference sound spectrum to estimate the resulting sound reduction provided by the components by the interior occupants.

Impact Sound Transmission helps identify an acoustical product’s response to impact noise and how it is transferred from one room to the space below. Dealing with single or multi-family dwellings, where the presence of people in a room above can be detected daily through footsteps or objects being dropped, results in the necessity to verify the ability of an acoustical product to mitigate those sounds. A standard tapping machine creates a steady source of impact vibration on the floor surface while measuring the impact sound pressure levels (ISPLs) in the room directly below the partition.

Impact Insulation Class (IIC) is a single number rating used to evaluate the effectiveness of a floor/ceiling system at reducing both high-frequency and low-frequency impact sound transmission in a laboratory. This rating evaluates the performance of an entire floor/ceiling system.

High-frequency Impact Insulation Class (HIIC) is a single number rating used to evaluate the effectiveness of floor systems at reducing high-frequency impact sound transmission in a laboratory. Through years of data, it has become apparent floor toppings and underlayments have a much greater effect on the high-frequency IIC performance of a floor/ceiling system. The HIIC rating was developed to accurately evaluate the variances in flooring and underlayment performance that is not always apparent in IIC ratings.

Delta Impact Insulation Class (Delta IIC) is a single number rating used to evaluate the effectiveness of a floor topping at improving IIC performance. This test is run exclusively on a concrete slab and compares the IIC performance of the slab itself with the IIC performance of the slab with the added floor topping. The difference between the two IIC ratings is used to determine the Delta IIC, a representation of the improvement provided by addition of the floor topping to the system.

Conclusion

Ultimately, the real purpose of designing for good acoustics is to improve the lives of the people occupying a space. Unwanted sound (noise) allowed to enter from outside of a building can be distracting or even harmful to people inside. The use of tested acoustical products and the expertise of an acoustical consultant can help building owners avoid post-construction complaints from the people occupying the building. By taking a holistic approach to acoustical design as an integral part of architectural and interior design, a comprehensive, quieter, and more peaceful result can be achieved.

Notes

¹ Review “The Adverse Effects of Noise Pollution on Humans and Animal Health,” at https://helpsavenature.com/noise-pollution-effects.

² For more information, read “What Are the Harmful Effects of Noise Pollution?” by Bhishm Khanna at www.researchgate.net/post/What_are_the_harmful_effects_of_noise_pollution.

³ See Health Effects from Noise at https://en.wikipedia.org/wiki/Health_effects_from_noise.

Author

Jeff Fullerton has nearly 30 years of experience providing acoustical consulting guidance to clients on local, regional, national, and global projects. His past projects include mixed-use facilities, entertainment venues, corporate and commercial buildings, single and multi-family residences, higher education buildings, government facilities, transportation terminals, healthcare facilities, and industrial plants. Fullerton’s passion for his work derives from a blend of his mechanical engineering education and many years of technical production experience backstage within performing arts centers. His consulting provides timely and high-quality recommendations his clients value for the success of their projects. His involvement is frequently sought, contributing as a team player and collaborating with others to accomplish the common goals of the project.