Optimizing acoustics with stone wool ceilings

by arslan_ahmed | January 25, 2023 9:00 am

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By Rebecca Silva

Grundfos, a global leader in water technology based in Bjerringbro, Denmark, has earned Leadership in Energy and Environmental Design (LEED) Platinum certification for its new Global Water Utility Headquarters—the highest available building certification through the U.S. Green Building Council (USGBC). Advanced stone wool ceilings for acoustical performance were key to the LEED Platinum certification.

The company demonstrates its commitment to sustainability at a global and local level, pioneering solutions to the world’s water and climate challenges, and to improving the quality of life for people. Its new regional headquarters opened in 2021, located in Brookshire, Texas, approximately 48 km (30 mi) from downtown Houston.

“Grundfos has manufacturing that already existed in Brookshire. We decided we wanted to be near this location for customer visits, the market for available technical skills, and proximity to educational institutions,” says Michael Franzen, senior regional manager for facilities and machining at Grundfos Global Water Utility Headquarters. The 4180 m² (45,000 sf) facility houses more than 100 employees working in sales, operations, engineering, human resources (HR), finance, and other support functions.

“From the beginning, we wanted the design to be a culmination of Danish architecture and Texas style. Sleek, modern, and simplistic,” says Franzen. “The initial design was developed by Grundfos architects, who then collaborated with the selected general contractor. The design was based on our needs, values, and sustainability initiatives.”

Based in Houston, Harvey Builders served as the project’s contractor, collaborating with architectural firm PGAL and acoustic engineer SLR Consulting. The project team recognized that advanced acoustic stone wool ceiling systems throughout the entire workspace were necessary to meet the project’s aesthetic, performance, and sustainability goals.

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 Key considerations: Acoustics

“Acoustics were a key consideration, because of the open concept and design,” says Franzen. “On the first floor, the conference and meeting rooms were an important focus. There are eight areas specifically designed as quite spaces and private areas for employees, two specifically designed collaboration lounges, as well as a courtyard with tables, lounge seating, and ping pong.”

He emphasized that acoustic optimization in open spaces “was a particular concern as we have hard surface floors on 85 percent of the first floor” with 4.8-m (16-ft) ceilings.

SLR Consulting’s project engineer, Nick Block, PE Acoustics, LEED AP, assisted PGAL with performance-based ceiling product selections. “Our involvement was to work with the project team to help secure the EQc9 Acoustic Performance credit under the LEED rating system,” Block explained. “Grundfos was very particular about their acoustic goals and have their own acoustic guidelines.
Our scope pertained to meeting LEED acoustic guidelines, namely reverberation time and mechanical noise.”

Intent on meeting the acoustics requirements in LEED, Block contacted an acoustic specialist in Chicago to learn more about the performance
of stone wool ceiling systems. “[They] assisted by providing us with the acoustical data we needed to analyze their product line to find the right fit for both our acoustical requirements and aesthetic requirements by Grundfos and PGAL,” says Block.

SLR shared that the acoustic requirements for the suspended ceilings included a high Noise Reduction Coefficient (NRC) of 0.90-0.95. NRC is the metric used to describe the sound absorbing capability of an architectural surface material or finish. Additional sound isolation beyond what a typical fiberglass ceiling panel could provide was also necessary due to potential noise generated that the HVAC system in the plenum above the ceiling generated.

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Using laboratory test data, the acoustic specialist confirmed that the stone wool ceiling panels would adequately attenuate the mechanical equipment noise in the plenum. To produce an optimal acoustic experience which complied with the LEED acoustic requirements—the final design combined sound-absorbing stone wool ceiling systems with an NRC of 0.95, sound-insulating full-height walls with the correct sound transmission class (STC) rating and appropriate background noise levels.

After the ceiling was installed, SLR tested the system to confirm it performed as per the specifications.

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“Sound-absorbing ceiling tiles were the primary method of reducing the reverberation time in occupied spaces to a level that met the LEED criteria,” says Block. “The ceiling tiles were also important for reducing mechanical noise from VAV [variable air volume] and other equipment in the plenum space.”

“We ended up with large open areas that do not feel or sound acoustically empty,” says Franzen.

Occupant comfort and well-being

Sustainability and acoustical performance objectives were top priorities for the company, as well as its partners, PGAL, SLR, the building team contractors, product manufacturers, and others. PGAL associate, Ryan Bass, American Institutes of Architects (AIA) says, “Platinum certification was Grundfos’ edict and a contract parameter. The acoustical performance was one of those many unnegotiable credits that had to be met.”

According to the World Green Building Council (WorldGBC), more than 90 percent of an organization’s operating costs are linked to employee efficiency. Therefore, workspaces design in the headquarters needed to facilitate the attraction and retention of talent, enhance employee comfort, heighten concentration, reduce stress, and enhance job satisfaction.

Surveys of office workers show their acoustic experience is one of the lowest ranking categories. Research shows people working in offices spend 62 percent of their time doing quiet work. The noise within their surrounding environments influences their accuracy, efficiency, productivity, and well-being.¹

As the amount of sound absorption is increased inside a room, the reverberation time and noise levels decrease. This improves speech intelligibility, privacy, and comfort so employees can perform at their best. Even small changes in the acoustic experience may have a significant impact and a positive effect on the bottom line.

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Daylighting and Danish design

The bright white, acoustic stone wool ceiling panels in Grundfos Global Water Utility Headquarters reflect 85 percent of light from their surface. The diffused lighting manages glare on computer screens and monitors, contributing to a comfortable, productive working environment. It also supports energy efficiency by optimizing electric and natural light, and bringing daylight more deeply into the office interior.

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For precise, technical alignment and a crisp perimeter, the design called for a proprietary modular ceiling system where the layout integrated linear light fixtures.

“The lighting and reflectance values of all finish surfaces was another critical aspect of design with LEED lighting quality and daylight credits,” says Bass. “These were also non-negotiable credits to achieve, and the reflective quality of the smooth white panels was a critical component, especially to offset the darker non-reflective floor finishes.”

Franzen elaborated, “The lighting system in the building is all controlled with occupancy sensors. Our sustainability commitment was executed in the design by incorporating solar panels to provide a minimum of 20 percent of our electricity. We have solar hot water heating for our potable water. We have a 100,000-gal [37,854-L] rainwater harvesting system that provides graywater for use in the building and is the source of water for our HVAC system. We estimate this will reduce our municipal water usage by 87 percent. The HVAC system is designed using pumps and technology to reduce energy consumption and increase comfort.”

Along with supporting energy-efficient lighting, the white ceilings’ neat, clean appearance also highlights the desired, contemporary architectural style.

“Grundfos’ own Danish architect and engineers drove the design and aesthetic choices,” says Bass. He added that PGAL articulated the “strict aesthetic ideals through modern and simple details with all lines as well aligned as possible.”

Creating visual continuity and uniformity throughout the office’s open floor plan, PGAL chose large-format ceiling panels with a fully concealed edge design. The close-fitting edges of the panels minimize the visible grid in favor of
a monolithic feel.

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Earning LEED Platinum

“Our buildings are built according to the level of the LEED certification, regardless of whether we choose to obtain the certification itself,” says Lars Oest Jacobsen, lead project manager at Grundfos Group Facility.

Locally sourced and environmentally responsible building materials were verified for the building’s construction and interior build-out to earn LEED Platinum certification. Following LEED criteria, the headquarters will reduce carbon emissions, energy use, water consumption, and landfill waste.

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PGAL’s design team specified acoustic stone wool ceiling panels and metal ceiling suspension systems. Helping them make informed decisions about material ingredients, the ceiling system manufacturer also offered health product declarations (HPDs), and UL-certified environmental product declarations (EPDs).

These low-emitting products contribute to healthy indoor air quality. Stone wool products are available as UL Environment’s GREENGUARD Gold certified for low volatile organic compounds (VOCs) emitting materials in offices, as well as other spaces (i.e schools). This stringent certification is recognized by numerous green building and wellness programs, including LEED.

“The Indoor Air Quality [IAQ] and VOCs were another non-negotiable LEED credit to achieve that this ceiling product complimented,” says Bass. He also noted that the GREENGUARD certification also played a crucial role in meeting LEED materials and resources category credits.

Sourced from abundant basalt rock, stone wool naturally resists the growth of mold, mildew, and potentially harmful microorganisms, without the use of added antimicrobials, biocides, or fungicides. The stone wool ceiling panels include no fire-retardant chemicals and achieve Class A fire performance. Both the stone wool ceiling panels and its metal suspension systems are made with recycled content. At the end of their life on the building, the suspension systems are also 100 percent recyclable.

The stone wool ceiling panels on Grundfos’ new regional headquarters require minimal maintenance throughout their long lifecycle and are backed by a 30-year warranty.

“Ceiling resiliency, like all finishes, is a critical feature to ensure the best long-term investment,” says Bass.

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 Aligned values, shared vision

This construction, in addition to its manufacturing energy- and water-efficient pumping solutions, underscores Grundfos support for the United Nations’ Sustainable Development Goals (U.N. SDGs). Water affects 15 of the 17 U.N. SDGs. In particular, the company’s worldwide operations strive to make a difference in SDG 6, clean water and sanitation, and SDG 13, climate action.
This focus also allows Grundfos to help other companies be more sustainable and reach the SDGs together.

Like Grundfos, some of the product manufacturers involved in its new Texas-based regional headquarters share a commitment to the U.N. SDGs. In addition, at least one company joins Grundfos as a participant in the U.N. Global Compact, upholding 10 principles in the areas of human rights, labor, anti-corruption, and the environment.

Grundfos and its partners also join with companies worldwide in leading the zero-carbon transition by setting emissions reduction targets through the Science Based Targets initiative (SBTi). Science-based targets provide companies with a clearly defined path to reduce emissions in line with the Paris Agreement goals.

Notes

¹ Refer to the research paper, Disproving widespread myths about workplace design.
Visit https://www.researchgate.net/publication/248708306_Disproving_widespread_myths_about_workplace_design[10].

Author

Rebecca Silva is the district sales manager at Rockfon North America, based in Houston, Texas. She works closely with architects, specifiers, and distribution centers for their acoustic ceiling selections. She is passionate about the impact ceilings can have in traditional open spaces and workspaces, as well as educational and health care spaces. Silva can be reached at rebecca.silva@rockfon.com.

Source URL: https://www.constructionspecifier.com/optimizing-acoustics-with-stone-wool-ceilings/

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