Acoustic ceilings providing comfortability throughout indoor settings

by brittney_cutler_2 | May 24, 2022 3:00 pm

Photos by Tom Arban Photography Inc./courtesy Rockfon

By Diana Hart

Specification professionals are expected to evaluate products’ performance, durability, and longevity. Increasingly, product ingredients’ chemistry and composition have been added to this list. Product transparency, material disclosure, and acoustic optimization are recognized and rewarded by the Canada Green Building Council’s (CaGBC) Leadership in Energy and Environmental Design (LEED) version-4 rating systems, the International WELL Building Institute (IWBI) WELL Building Standard, and other sustainability standards.

Material disclosure and transparency

Whether or not a building team pursues LEED or WELL certification for a project, there is an increased emphasis on choosing products that support indoor environmental and air quality and contribute to healthy and comfortable interior spaces. Often, this requires working with manufacturers to gather the necessary documentation to evaluate products’ claims and composition.

For acoustic ceiling products, examples of relevant documentation include the following.

Environmental product declarations (EPDs)

An EPD is a disclosure tool that details a product’s sustainable qualities and environmental impact over its lifespan. EPDs can be developed after a product life cycle assessment (LCA) is conducted and are based on applicable product category rules (PCRs).

Exemplifying product transparency and accessibility, look to ceiling product manufacturers who offer third-party, industry-wide, cradle-to-grave EPDs on-demand by digital download. Complementing product specific EPDs, industry average EPDs also are available from industry associations. Both manufacturer-supplied product specific EPDs and association-supplied industry average EPDs may be third-party verified. For example, the Ceilings & Interior Systems Construction Association (CISCA) offers EPDs on aluminum and steel ceiling materials that are Underwriters Laboratories (UL) certified.

Health product declarations (HPDs)

HPDs are publicly available and published through the Health Product Declaration Collaborative’s Open Standard[2] version-2.2. This voluntary, standard format uses basic inventory methodology for reporting product-level thresholds and compositional chemistry down to 1000 parts per million (ppm). It can be searched by CSC/CSI MasterFormat division and section, such as 09 51 00 Acoustical Ceilings, and refined by manufacturer, product name, and other filters.

International Living Future Institute (ILFI) Declare Label

The Declare Label 2.0 by ILFI supports the Living Building Challenge by providing a transparent materials database that project teams can select from to meet the Red List requirements. ILFI asserts, “The Living Building Challenge (LBC) Red List[3] represents the ‘worst in class’ materials, chemicals, and elements known to pose serious risks to human health and the greater ecosystem that are prevalent in the building products industry.”

Acoustic stone wool ceiling panels were installed in the academic and collaboration areas on the lower nine levels of Ryerson University’s Daphne Cockwell Health Sciences Complex, a 28-storey mixed-use tower in Toronto, designed by Perkins&Will.

GreenGuard Gold certification for low-emitting products

Acoustic ceiling products that have earned GreenGuard and GreenGuard Gold certification are listed in the SPOT by UL database. According to UL, “The GreenGuard Certification Mark communicates that representative samples of a product have undergone rigorous scientific testing to meet some of the world’s most stringent chemical emissions requirements.”

GreenGuard[5] certified products are recognized, referenced, or preferred by more than 450 federal purchasers, retailers, green building rating tools, and building codes around the world.

Helping specification professionals simplify the volumes of product data and certifications, mindful Materials (mM) provides a common platform where manufacturers clearly communicate product transparency and optimization information.

Manufacturers that have clearly established supplier code of conduct and have adopted the International Chamber of Commerce (ICC) Business Charter for Sustainable Development ensure the component and material ingredient suppliers meet their standards. Manufacturers that carefully manage their supply chains also will be aware of their products’ material ingredients including their recycled content.

Acoustic ceiling panels made from stone wool consist of a blend of naturally occurring, volcanic basalt rock and recycled content. The stone is a plentiful, natural resource and high-tech production processes allow for environmentally responsible, efficient product manufacturing. On average, ceiling products with a stone wool core contain up to 43 per cent recycled content. A metal ceiling system can be specified with up to 100 per cent recycled material content and is 100 per cent recyclable at the end of its useful life on a building. Stone wool may also be recycled.

Companies that publicly and regularly share sustainability reports also demonstrate their commitment to transparency and continued improvement.

The Royal Alberta Museum in downtown Edmonton, designed by DIALOG, features selected galleries with black stone wool ceiling panels that offer optimal sound absorption with a noise reduction coefficient (NRC) of 1.05.

Healthy indoor air quality for all

“Healthy indoor air is recognized as a basic right,” states the World Health Organization (WHO)[7] guidelines for indoor air quality. “Knowledge of indoor air quality, its health significance and the factors that cause poor quality are key to enabling action by relevant stakeholders—including building owners, developers, users, and occupants—to maintain clean indoor air.”

Indoor air quality is more commonly referred to by its abbreviation, IAQ. In LEED version-4, the relevant category is called Indoor Environmental Quality and abbreviated as EQ. Regardless of the name, key factors affecting IAQ and EQ can involve pesticides and biocides, carbon monoxide, carbon dioxide, radon, solvents, volatile organic compounds (VOCs), allergens, moulds, asbestos, and other particulate matter. Using low-emitting building products and materials, and acoustic treatments in interior spaces contribute to healthy IAQ and EQ, current green standards, building codes, and regulation.

With poor IAQ, high levels of contaminants, chemicals, carbon dioxide, and other pollutants can lead to bad odours and irritation that cause people to lose concentration. Exposure can result in itchy eyes, nose, throat, and skin; headaches; dizziness; fatigue; shortness of breath; hypersensitivity and allergies; sinus congestion; coughing and sneezing; and nausea. Long-term or excessive exposure is linked to respiratory and heart diseases, and cancer.[8]

IAQ is stated or implied in most Canadian building codes as design and operation criteria. For guidance, building codes and health and safety legislation in Canada usually refer to a version of the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) Standard 62.1 Ventilation for Acceptable Indoor Air Quality[9].

Protecting the most vulnerable

Designed by DIALOG, Enbridge Centre’s Class AA office building in Edmonton, Alberta, uses acoustic stone wool and metal ceiling systems to enhance the space’s modern appearance and support Leadership in Energy and Environmental Design (LEED) attributes.

The average person spends approximately 90 per cent of their time indoors, where the concentrations of some pollutants can be two to five times higher than outdoors. People who are often the most susceptible to poor IAQ[11] tend to spend even more time inside, including those with compromised health and chronic illnesses, the elderly, and children.

Children need to breathe in more air than adults and, as a result, are absorbing more chemicals that can be harmful to their growing bodies, development, and ability to learn. Since most children spend most of their time inside schools and daycare facilities, these projects deserve extra attention when designing and specifying for air quality.

IAQ in Canadian school systems “is inadequate and the consequences include significant health effects to the children, teachers, and staff who occupy the school buildings,” according to Management of Indoor Air Quality in Canadian Schools. This 1998 research paper by Karen Beaulieu, a master of environmental design graduate student at the University of Calgary[12], surveyed 293 Canadian school systems representing every province and territory, and conducted follow-up interviews with selected personnel.

While nearly every Canadian school has made improvements and investments in their buildings’ IAQ during the 25 years since Beaulieu’s research, her paper continues to provide insight and value. Among these, the paper highlighted building products and materials can be important sources of IAQ contaminants. Ceiling tiles are specifically listed among these potential sources.

Addressing the role that all building products and materials play in IAQ, Beaulieu recommended:

“When designing a new building and when undertaking renovations, designers should discuss their indoor air quality concerns with manufacturers and suppliers and select the lowest-emitting materials and processes available.”

She continues by noting a careful selection of materials will minimize the potential for contamination through the processes of:

∞ emission of chemicals from the materials.

∞ release of particles from the materials.

∞ growth of microbial contaminants on materials that sustain moisture.

∞ emission of chemicals from materials that have absorbed the chemicals from surrounding air.

∞ maintenance and refinishing requirements of materials requiring additional chemicals.

Beaulieu’s IAQ recommendations remain consistent with many of those shared in the WHO’s IAQ guidelines, in the 2003 Indoor Air Quality – Tools for Schools Action Kit for Canadian Schools by the Minister of Health, and with current (2021) IAQ[13] information offered on the Canadian Centre of Occupational Health and Safety (CCOHS)[14] website.

Joy Ottereyes Rainbow Memorial School in Wemindji, Quebec, was designed by Figurr Architects Collective for the Cree School Board. Sound-absorbing stone wool panels and a metal perimeter trim create suspended ceiling systems in grid and cloud forms, to help optimize acoustics for learning.

All three sources noted the benefit of selecting low-emitting building products for new and renovation projects. These resources also emphasized concern for managing moisture and preventing the growth of mould and the propagation of other microbial contaminants.

More on mould and microbes

Under warm, moist conditions, mould can grow out of sight on construction materials and on interior finishes. Mould thrives when a spore lands on a surface where organic food (such as fibres, starches, and cellulose) and moisture are present, and temperatures are 5 to 38 C (40 to 100 F). Mould can grow rapidly in as little as 24 hours.

If stains and mould become visible on the room-side surface of ceiling panels, it is an indication that microbial contaminants may be extensive, affecting the air quality and becoming a concern for the occupants’ health, and eventually, buildings’ structural integrity and long-term value.

As part of mould prevention and interior moisture control, one must be aware of managing relative humidity and condensation. For example, some schools may turn off their HVAC systems during the summer months, thereby increasing the potential for the growth of mould and mildew. CCOHS[16] notes, “Relative humidity levels above 70 per cent may lead to the development of condensation on surfaces and within the interior of equipment and building structures. Left alone, these areas may develop mould and fungi.”

Following controlled humidity and temperature protocols outlined in ASTM International’s D3273-21, Standard Test Method for Resistance to Grown of Mold on the Surface of Interior Coatings in an Environmental Chamber, the surface of ceiling panels and other finishes can be tested to evaluate their resistance to microbial growth. In compliance with this qualitative testing standard, a material test sample is suspended in an environmental chamber above the organism species in soil. The three-tested organism species are aureobasidium pullulans, aspergillus brasiliensis, and penicillium citrinum.[17]

The sample material’s surface is examined under a microscope before the test begins and at the 28-day incubation period. The level of fungal defacement on the test sample is rated on a scale of zero to 10, where 10 indicates no visual defacement. For greater confidence in specifying mould-resistant surfaces, check with acoustic ceiling product manufacturers to review whether their products have been tested to ASTM D3273-21.

Specialty and controlled environments, such as clean rooms and medical establishments, require an even greater level of assurance. The internationally recognized Norme Française (NF) S 90-351:2013-04, Établissements de santé – Zones à environnement maîtrisé – Exigences relatives à la maîtrise de la contamination aéroportée, currently is considered the most stringent test standard within the industry concerning the control of airborne contamination. There is no equivalent for NF S 90-351:2013 in Canada or the U.S[18].

NF S 90-351:2013 requires material test samples meeting this standard are exposed to aspergillus brasiliensis, candida albicans, and methicillin-resistant straphlococcus aureus (MRSA). Stone wool ceiling panels have achieved an M1 classification, fulfilling the requirements of Zone 4, the standard’s highest risk category.

Ceilings composed of organic fibres and water-based materials need to add a biocide, fungicide, or antimicrobial to help protect against the mould and mildew. With the added chemicals, these materials may become a potential pollutant source contributing to poor IAQ. Other disadvantages of using antimicrobials can include increased resistance to antibiotics, a false sense of security, and increased costs.

Supporting health and wellness, acoustic stone wool ceiling panels with a noise reduction coefficient (NRC) of 0.90 were installed throughout Humber College’s Humber Interactive Space (HIVES). The space designed by Montgomery Sisam Architects is located on the college’s north campus. Photo by Shai Gil/courtesy Montgomery Sisam Architects Inc.

Stone wool and metal are inherently mould-resistant materials, and easy to clean without harsh chemicals. They are not organic and, therefore, they do not provide sustenance to mould, mildew, bacteria, fungi, and other micro-organisms. The stone wool is also hydrophobic and repels water, moisture, and humidity.

Beyond mould mitigation, ceiling panels that resist moisture and humidity do not sag, warp, rot, or fall out as a result of water absorption. Hydrophobic materials like stone wool support good IAQ by alleviating concerns associated with supplemental natural ventilation from operable window systems, or when HVAC systems are turned off when the building is unoccupied. This moisture-resistant attribute can also assist during buildings’ construction schedules by allowing ceilings to be installed prior to the envelope being completely sealed or the HVAC made operational.

Achieving higher IAQ objectives with lower emitting ceiling products

Products verified and certified for low VOC emissions not only support IAQ and EQ objectives, but also material ingredient reporting and transparency criteria by CaGBC’s LEED version-4.1 and IWBI WELL version-2. The documented advantages of low-emitting products also are recognized by Building Research Establishment Environmental Assessment Method (BREEAM) Canada, Collaborative for High Performance Schools (CHPS) Criteria, Center for Active Design (CfAD) Fitwel global healthy building certification, and other programs promoting sustainability and wellness goals.

Supporting these goals, acoustic ceiling materials with natural resistance to mould and low VOC emission levels are readily available in North America. Metal ceiling systems have no reportable emissions from VOCs. A wide range of acoustic stone wool ceiling products have earned UL Environment GreenGuard Gold certification for low emissions and are available with ILFI Declare Label 2.0 supporting the Living Building Challenge (LBC).

The LBC 4.0 standard’s Imperative 10 requires all interior building products that have the potential to emit VOCs to demonstrate their compliance. Further, Imperative 13 requires manufacturers to disclose the ingredients in their products to ensure they are free of Red List chemicals. Included on the LBC Red List are VOCs in wet-applied products, monomeric and polymeric flame retardants, and antimicrobials marketed with a health claim.

The Declare Label database is freely available to design and specification professions. Products can be searched by ILFI program, alignment with LEED and other programs’ criteria, manufacturer, location, CSC/CSI MasterFormat division, and declaration status. Nearly 100 ceiling product types are listed under ‘09 50 00 Ceilings,’ with each having one of three types of declaration status:

∞ Declared—This indicates 100 per cent disclosure but contains one or more Red List chemicals that are not covered by an existing exception.

∞ LBC Red List Approved—This indicates a minimum of 99 per cent disclosure but relies on one or more exceptions to demonstrate compliance.

∞ LBC Red List Free—This provides the highest assurance, indicating 100 per cent disclosure and that the product does not contain any chemical on the LBC Red List[20].

One must be aware, there also are two tiers of GreenGuard certification, with Gold being the more stringent. According to UL Environment:

∞ “Products that have achieved GreenGuard certification are scientifically proven to meet some of the world’s most rigorous, third-party chemical emissions standards, helping to reduce indoor air pollution and the risk of chemical exposure, while aiding in the creation of healthier indoor environments.”

∞ For next-level verification, products that earn the GreenGuard Gold certification standard also meet “health-based criteria for additional chemicals and also requires lower total VOC emissions levels to help ensure products are acceptable for use in environments like schools and health care facilities.”

Specifiers should carefully review the GreenGuard Gold certification to ensure it complies with the project application. Remember, the larger the room, the greater its volume, which means there is more air to disperse chemical emissions. For example, the same emission levels will have a greater concentration and potentially greater effect in a small, enclosed office versus a large, spacious lecture hall.

To support health care and wellness, a range of stone wool products are Underwriters Laboratories (UL) GreenGuard Gold certified for low emissions, and naturally resist moisture, mould, and mildew without added fungicides.Photos by Tom Arban Photography Inc./courtesy Rockfon

Beyond IAQ with optimized acoustics

A room’s size, shape, function, and material selection not only affect occupants’ health, well-being, and productivity through its air quality, but also through its acoustic experience.

“Noise is one of the most common occupational health hazards,” according to the CCOHS[22]. “Permanent hearing loss is the main health concern. Annoyance, stress, and interference with speech communication are the main concerns in noisy offices, schools, and computer rooms.”

Effects of poor acoustics and IAQ in schools, offices, and other commercial interiors also include:

∞ increased absenteeism

∞ decreased job satisfaction and lower morale

∞ increased costs for substitute and replacement workers

∞ decreased accuracy and increased costs due to errors

∞ increased costs for building repairs, remediation, and insurance

∞ damaged relationships between building owners and occupants, supply chain and funding sources, and government and community leaders

“The best method of noise reduction is to use engineering modifications to the noise source itself, or to the workplace environment,” advised the CCOHS. Selecting and specifying acoustic ceiling panels with a high noise reduction coefficient (NRC), typically an NRC 0.90 or higher, can provide the necessary sound absorption to create a good interior acoustic experience.

Acoustic stone wool ceiling panels were specified by Montgomery Sisam Architects and the Architecture Council for Durham College’s Centre for Collaborative Education in Oshawa, Ontario. The panels provide high sound absorption, support indoor air quality, and maximize light reflectance.

LEED version-4.1 offers acoustic credits in three categories and WELL version-2 includes sound as one of its 10 concepts with eight corresponding features. Using a three-step approach to optimize acoustics supports these programs’ criteria and projects’ larger wellness initiatives.

∞ Firstly, selecting the appropriate NRC rating for ceiling panels, absorbing sound and controlling reverberation and noise.

∞ Secondly, selecting the appropriate sound transmission class rating for wall and floor-to-ceiling assemblies, preventing noise transfer between rooms using full-height walls.

∞ Thirdly, selecting the proper background sound levels, masking annoying or distracting noise.

In addition to acoustic comfort and IAQ, acoustic ceiling systems contribute to indoor environmental quality through improved lighting and energy efficiency. Specifying a bright white ceiling panel with a smooth surface for high light reflectance more efficiently utilizes electrically powered lighting and maximizes natural light. The diffused, reflected light reduces glare on screens and monitors, which lowers the likelihood of eye strain, headaches, and impaired concentration, further supporting occupants’ health and well-being.

With a clear connection between people’s health, specifying products related to IAQ and EQ becomes a critical consideration. Ceiling system manufacturers can support project requirements with product transparency, material disclosure, and with product solutions that offer natural resistance to mould and moisture, low VOC emissions, acoustic optimization, and high light reflectance. Thoughtful material production, selection, and specification will deliver the most advantageous outcome at the intersection of health, comfort, and sustainability.


[24]Diana Hart, CSI, IIDA, serves as manager of architectural sales and business development for Rockfon North America, part of the ROCKWOOL Group. Working with architects, designers, and specifiers, she helps in selecting advanced acoustic ceilings and wall solutions to create beautiful, comfortable spaces. She can be reached at

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