Voluntary acoustical guidelines and standards
The Optimized Acoustics design process can be used during the design and specification of learning facilities in Canada when no provincial or institutional requirements are applicable. In some cases, though, acoustical requirements may be provided by an independent, third-party, voluntary standard, guideline, or rating system that the building owner or design team has opted to adopt.
The American National Standard Institute’s (ANSI) standard S12.60, Acoustical Performance Criteria, Design Requirements and Guidelines for Schools, frequently is cited in building codes, standards, guidelines, certification programs, and rating systems throughout North America.
ANSI S12.60 requires:
- sound-absorbing finishes, such as acoustic ceilings, so RT inside classrooms is no more than 0.60 for smaller rooms and 0.70 seconds for larger spaces;
- full-height walls between classrooms that have an STC 50 rating; and
- mechanical system background noise to be below a maximum permissible level of 35 dBA.
Adopting ANSI acoustic standards was among the recommendations made in the Speech-language and Audiology Canada’s position paper calling for building code changes to improve classroom acoustics. Similarly, the Canadian Hard of Hearing Association’s Universal Design & Barrier-Free Access said this “standard provides excellent guidelines for acoustical performance and it should be followed in both adapting of classrooms to accommodate hard of hearing students and in new designs generally. The standard was motivated by research that shows that student performance generally is negatively influenced by noise and poor acoustics.”
Several voluntary, third-party building standards, guidelines, and certification programs championing sustainability and wellness also recognize people’s acoustic experiences contribute to their health and well-being. Many of these guidelines reference ANSI S12-60. Examples include:
- The Canada Green Building Council’s (CaGBC’s) Leadership in Energy and Environmental design (LEED) v4 for Interior Design and Construction requires classroom acoustics to have:
- maximum RT of 0.60 to 0.70 seconds and use of a high NRC ceiling panel;
- full-height STC 50 walls; and
- maximum background sound levels of 40 dBA, although 35 dBA is preferred.
2. Green Globes for New Construction (ANSI/Green Building Initiative [GBI] 01-2019, Green Globes Assessment Protocol for Commercial Buildings), has been used by the Canadian federal government for more than a decade. It requires:
- classrooms to have a RT of 0.60 seconds or less, and ceilings with an NRC 0.80 or higher;
- classrooms to have full-height walls with an STC 50; and
- maximum background sound levels of 35 dBA (according to ANSI S12.60).
3. the International WELL Building Institute’s WELL Building Standard v2 examines 10 concepts and 108 features. Its sound concept “aims to bolster occupant health and well-being through the identification and mitigation of acoustical comfort parameters that shape occupant experiences in the built environment.” The Sound Concept includes:
- S02 “Maximum Noise Levels” optimization feature—requiring background noise levels in speech rooms to not exceed 35 dBA, in focus rooms 40 dBA, and in activity rooms 45 dBA;
- S03 “Sound Barriers” optimization feature—requiring activity rooms be surrounded by STC 60 partitions, speech rooms STC 55 partitions, and focus rooms STC 45 partitions;
- SO4 “Reverberation Time” optimization feature—requiring areas for learning to have a RT less than 0.60 seconds for spaces up to 929 m2 (10,000 sf), 0.50 to 0.80 seconds for spaces between 929 (10,000) and 1858 m2 (20,000 sf), or 0.60 and 1 second for spaces larger than 1858 m2 (20,000 sf); and
- S05 “Sound Reducing Surfaces” optimization feature—requiring areas for learning, open workspaces, conference areas, and dining spaces have 100 per cent of the room’s ceiling area be NRC 0.90 or higher. Partial credit (one point) may be given for ceilings covering at least 75 per cent of the room with panels having an NRC 0.75.
Learning facilities and spaces include far more than schools, colleges, and universities, and the teachers and students within them are equally deserving of a positive acoustic experience. The recently renovated and re-opened Stanley A. Milner Library in Edmonton was designed to meet, or exceed, Alberta’s TDR acoustic performance requirements.
As the downtown branch of the Edmonton Public Library (EPL), the new Milner Library reinvented its former box-shaped structure into a flowing, angular, modern icon, and reimagined its interior as a brighter, quieter, more inviting, innovative, public space. The $84.5-million expansion and rejuvenation encompasses six floors and 21,368 m2 (230,000 sf). At its centre, a multi-storey atrium ascends within the building’s stacked floorplates, interspersed with exterior window views, and interconnected by light and openness.
Supporting the EPL’s and the library’s design goals, Teeple Architects selected four types of acoustic stone wool ceiling panels to contribute to the welcoming, comfortable, energy-efficient space, and to create a positive acoustic experience in a variety of different spaces.
The revitalized Milner Library’s design optimizes acoustics, categorizing each functional space or zone by its acoustic goals and utilizing an acoustic ceiling panel with the appropriate amount of sound absorption. Where high noise levels are expected or critical listening is required, the highest NRC of 0.90+ was specified. Where quiet concentration is needed or where a bit more excitement is desired, ceiling panels with NRC 0.80 are installed. In areas where less acoustic control is required, such as private rooms or circulation paths, lower performing panels of NRC 0.70 were used.
Finding a quiet space and avoiding noise was mentioned by 87 per cent of EPL’s customers in a 2012 survey. Staff interviews confirmed a concern regarding the noise level in the library. Computer areas and places where teens congregated were called out as being noisy. Many said they valued designated quiet places to read, study, work, or write.
Responding to this feedback, the new Milner Library features enclosed collaborative spaces for group work, children’s programming, and more lively activities. Computer and workstations are distributed more widely throughout the building. Quiet zones are designated for reading and other tasks requiring concentration.
Helping manage noise and optimize acoustics to match each area’s function, the four types of acoustic stone wool ceiling panels provide the necessary range of sound absorption throughout the project with NRCs of 0.75 to 0.95.
The majority of Milner Library’s acoustic ceiling systems feature a mid-range NRC of 0.85 on five of the six floors. These include the staff’s offices and amenities room, the server room and computer labs, the conference and meeting spaces, the main floor’s Shelley Milner Children’s Library, and the second floor’s enclosed reading room.
The reading room has been called “an island of serenity” within the Milner Library and Edmonton’s downtown core. It is equipped with comfortable seating and work tables, a community gallery wall, and views on the east and north side onto Churchill Square. Here, in the reading room and in many of the library’s enclosed offices, sound-absorbing ceiling panels combine with full-height walls and moderate to high background sound levels optimizing acoustics to provide privacy and focused concentration.
Speech intelligibility and privacy are especially important in The Robert Tegler Trust Outreach Service at the Milner Library. Based on EPL’s community-led service model and the belief that great libraries welcome everyone, the outreach service staff works with EPL’s most vulnerable customers to help and empower them through literacy, education, connections, and social support.
More than 3200 black panels with an NRC of 0.85 were selected for the first and second floors. These deliver the best sound absorption for the high-tech, high-energy atmosphere of the 3-D printing area, the black box studio and adjacent studio spaces, and above laptop bars. The most acoustically critical areas in the third floor required the high NRC of 0.95 provided by an additional 881 m2 (9488 sf) of black panels.
Ceiling panels with an NRC of 0.75 provide good sound absorption appropriately scaled for other areas’ functionality. These are installed on the first and second floors of library in its open common areas, above small group work areas, adjacent to the main circulation paths, and in other spaces where social conversations are expected.
In total, more than 6596 m2 (71,000 sf) of acoustic stone wool ceiling panels were installed throughout the new Milner Library.
Regardless of available standards, design professionals can ensure optimal acoustics in learning facilities by using the right combination of highly absorptive ceiling panels, robust walls and floor slabs, and the right level of designed background sound level. Remember to follow the three-step approach for best results:
- Acoustic ceilings are used to absorb noise and reverberation inside the room.
- Full-height walls and floor slabs block outside noise from coming into the space from above, below, or next door.
- Background sound is neither too quiet nor loud. Keep it low for speech and music rooms, and intentionally louder for focus and activity spaces.
Gary Madaras, PhD, is an acoustics specialist at Rockfon. He helps designers and specifiers learn the Optimized Acoustics design approach and apply it correctly to their projects. He is a member of the Acoustical Society of America (ASA), the Canadian Acoustical Association (CAA), and the Institute of Noise Control Engineering (INCE). Madaras can be reached at email@example.com.