Noise And New Developments: Sounding off on Ontario’s residential requirements

by Elaina Adams | March 1, 2012 2:49 pm

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By Ryan Bessey, P.Eng.
Basic acoustic requirements have long been part of the National Building Code of Canada (NBC), which is the model for the provincial codes, including the Ontario Building Code (OBC). The only demand is walls surrounding residential suites must be documented to meet a specific sound isolation performance. The limitation of this requirement is actual field sound isolation performance can vary greatly from the documented value due to various factors.

To address the sound isolation issue (along with other acoustic concerns) for Ontario, the Tarion Warranty Corp., which issues warranties on the province’s residential construction, has stepped in. It now compels developers to prove their new condominiums meet specific acoustic standards before being enrolled under the Ontario New Home Warranty Program. These new requirements are catching many developers off-guard in a booming condominium market.

In its recently revised Builder Bulletin 19R (July 1, 2010), Tarion has added ‘acoustics’ to the list of identified risk areas that must be considered before a condominium development can be enrolled in its new home warranty program. In other words, after the building’s design is complete, but before construction can proceed, a design certificate must be prepared by an acoustical engineer for review.

The simplest and most efficient method for certification is to have the acoustical engineer involved in the design of the project from the beginning. Otherwise, a detailed acoustic review must be conducted at the end of the design phase and if any issues are discovered, aspects of the building may require re-design. This can wreak havoc with schedules and project costs.

In the case of one Toronto condo tower, while the high-value penthouse suite offered a sweeping skyline view, analysis of the plans from an acoustic engineering perspective showed those living on the top floor might also have an unexpected additional feature—noise from the mechanical penthouse located directly overhead.

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It was clear to the acoustical engineers brought in to provide advice on this project that, as designed, the floor-ceiling assembly would not be enough to keep sound from the mechanical room above from reaching the unit below. Whether from the continuous noise of the building’s chillers or, even worse, when the diesel generator was operated as part of mandated monthly testing, the sound level would be such that the penthouse suite’s presumably well-heeled owners might make some legal noise of their own. This is one clear example of a design issue a good acoustical engineer could catch, preventing an expensive post-construction headache.

Importance of inspections
Having an acoustically certified design is not enough, as there is no guarantee the final construction will be built or perform exactly as designed. To address this concern, Tarion requires inspections and field testing take place to catch any acoustic deficiencies and verify performance before the building is handed over.

Since inspecting and testing every room of a large condominium is far from practical, acoustical engineers focus on a statistically representative sample of key risk areas. The number of inspections, along with the quantity and type of tests, is subject to Tarion’s approval, but also based on the expertise of the acoustical engineer.

Where the problems lie
In order to accommodate anticipated differences between design data and field performance, the onus is on the design team—which should include the acoustical engineer—to provide plans that hold up well during field testing. This approach may require designing suite walls, mechanical systems, and exterior façades to tighter tolerances than to which some developers are accustomed. As a result, achieving compliance is not always a straightforward matter.

Acoustic problems due to poor construction are increasingly common in condominium towers. Part of this is due to pressures on crews to reduce costs, possibly through cutting corners on materials and labour, or simply not understanding the nuances of acoustic construction techniques. These may show up when the unit’s occupants find they can hear their neighbours’ conversations, or are disturbed by HVAC, garbage chutes, parking garages, or elevator noise. Instead, a good acoustical engineer can identify these issues through site inspections or field testing.

As more urban infill units are built close to busy roadways, there is greater potential for exterior noise to intrude. Combine this with the floor-to-ceiling glazing popular in today’s condo market, and the potential for sound issues further increases. It is important the glazing’s acoustic performance be carefully specified to ensure both unit owners and condo developers will have restful nights.

With the increased prevalence of subwoofers in sound systems, and the growing popularity of wall-mounted wide-screen monitors with built-in rear-firing speakers, entertainment technology is playing a role in generating new types of potential noise complaints. As the guidance documents from Tarion suggest, buildings should be designed with respect to good acoustical engineering practices, addressing these new types of noise issues.

Overall, acoustics have come more to the forefront of Ontario builders’ consciousness with the inclusion of noise-related requirements in the home warranty program. Consequently, there is a lot more noise about noise, when it comes to high-rise condominium developments. How does a builder make it less likely acoustic considerations will force a costly retrofit, turning what could have been a profitable venture into a costly learning experience?

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Bring acoustic considerations in early
Acoustical engineers sometimes find themselves called into a project late in the design phase, perhaps asked to review and sign off on plans after the detail work has been done. In such cases, they may discover issues such as a racquetball court or weight room designed without adequate measures to protect the adjacent units from vibration and noise. At this point, reworking the plans to deal with the issues, or design of sound isolation measures may be onerous indeed.

Acoustical engineers provide their best value when brought into the design process early, well before detailed work is done. They can point out issues that may require costly design solutions down the road, which can often be eliminated through careful space planning. The result can be a low-cost change made to the plans to help the building meet acoustic requirements. The engineers can also point out potential trouble spots such as inadequate space between walls that may allow certain noises to be transmitted from one unit to another.

Revisions made in the early design phases can eliminate the need for more costly changes later or even more expensive alterations to completed construction, including post-sale retrofits.

How design and materials affect acoustics
It may be impossible for builders to stay current on all the factors affecting a project’s performance—they must be able to depend on specialized professionals such as acoustical engineers for advice. However, they should also be educated about some of the more common factors influencing acoustics.

These factors might include simple steps such as using caulking to seal the gap that often occurs where a wall’s gypsum wallboard meets the floor. These gaps can allow sound to leak from one unit to another. Or, it could be installing electrical outlets opposite each other creates a pathway for sound to travel easily between units.

Another factor might be the correct installation of noise control materials. For example, a design might specify resilient channels to decouple walls from supporting studs for increased sound-isolation performance. However, this author’s experience shows work crews will sometimes put their drywall screws in too far, directly connecting the drywall to the stud. The result serves as a conductor for noise between units.

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As another example, sometimes deficient walls are discovered where the builder simply forgot or neglected to put insulation in the wall cavity. These examples demonstrate crews must be reminded of the importance of proper installation techniques, as these types of mistakes easily result in decreased sound isolation performance, failed field tests, or, in the worst cases, annoyed residents.

Check to see reality matches the plans
Just as project owners keep watch over the construction process to ensure the trades and subs are following the plans and carrying out good practices, they need to be certain noise-management issues are met. As part of the Tarion field review process, acoustical engineers are required to make random inspections of the work in process, carrying out tests of completed sections of the work.

Beyond this, project owners need to keep themselves informed about acoustic issues in their buildings so they too can ensure there are no short-cuts being taken that will impair acoustic performance.

Acoustical engineers can provide good advice during the construction phase. This could be particularly useful if builders find the construction cannot proceed according to plan; for example, it may turn out there is no room to install recommended noise controls. The acoustical engineer could then make recommendations on alternative solutions that will fill and still provide the required degree of acoustical performance. For example, it may be possible to use a shorter silencer in combination with lined ductwork if the required silencer will not fit in the mechanical room.

The science of acoustics as applied to construction is constantly changing, in part because new construction materials are always being introduced, and these may have acoustic implications. Some proprietary formulations of wallboard can deliver better sound isolation performance due to increased mass and damping than traditional products. However, many condominium developers can seek out lower-cost ways to achieve similar results. For instance, it is possible to increase wall mass by doubling up drywall layers. Additional sound-damping can be added by specifying relatively inexpensive visco-elastic glues.

The National Research Council Institute for Research in Construction (NRC-IRC) tests construction materials and methods, and publicizes its findings in its Construction Technology Updates (CTUs). (The CTUs are available online at www.nrc-cnrc.gc.ca/eng/ibp/irc/ctus/ctus-index.html[5]). From CTU 1 that discussed “Control of Sound Transmission through Gypsum Board Walls” in 1997, to CTU 27 on the “Effect of Electrical Outlet Boxes on Sound Isolation of Gypsum Board Walls” in 1999, to the more recent CTU 66 on the effect of flanking transmission in “Airborne Sound Insulation in Multi-family Buildings” in 2008, the NRC resources have a history of providing  concise summaries of valuable research that acoustical consultants all over the world review and that every builder needs to know.

Conclusion
For all condominium developers, building a trusting relationship with a professional firm that offers qualified acoustic and vibration services is the first step to meet with the new requirements of Tarion Bulletin 19R. Having an acoustical engineer involved with the condominium design can result in a smoother-running project, lower costs, and more satisfied owners. The key is to get an acoustical engineer involved in the project as early as possible.

Ryan Bessey, P.Eng., is an acoustical, noise, and vibration engineer with Golder Associates Ltd., based in the company’s Toronto office. He has 10 years of experience helping builders manage acoustic issues. Bessey can be reached via e-mail at ryan_bessey@golder.com.

Source URL: https://www.constructioncanada.net/noise-and-new-developments-sounding-off-on-ontarios-residential-requirements/

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