Sound advice on contract administration for acoustics

acoustics_26 - Pyatt Hall
Photo courtesy Larry Goldstein

By John O’Keefe, M.Sc., P.Eng., FIOA, and Kiyoshi Kuroiwa, B.A.Sc., P.Eng
A building is an assembly of various materials intertwined to construct something solid and enduring. However, even small adjustments in a building’s plan can lead to unforeseen problems, especially to acoustics and noise control performance.

Acoustics and ambient noise are common complaints, but relatively small changes can have big acoustical implications. For example, while moving a wall to a different location may seem like an easy revision in the building stage, this can cause a troublesome echo that has a snowball effect on the floor’s acoustics.

Governed by the laws of physics, acoustics is a science that either helps or hinders the ability to clearly hear sound. From too much ambient noise to too much echo, there are many things that can go wrong acoustically in a building under construction. The science of architectural and environmental acoustics has advanced, and they have been incorporated into the design of projects. These advancements have come a long way to influence the design process; however there are numerous ways to compromise the acoustic design.

Sometimes, noise control and acoustics can be restored after the building is finished, but usually at a steep price. The positioning of lights or the adjustment of door seals can easily be changed post-construction; however, noise control elements are often hidden. This means correcting the problem usually requires breaking down walls to locate the source. This can add time and complications, as well as put a strain on budgetary requirements for the owner or contractor.

Post-construction hassle can be avoided by having contract administration handled by someone with an acoustical background. Careful review of the contract requirements and onsite inspections at key points during the construction process help maintain the design’s acoustic integrity and ensure the ultimate acoustic goal is achieved. If possible, adding a section in the specifications stating a start-up meeting is required to outline expectations and review acoustical mock-ups, should be considered.

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What is contract administration?
Every construction project should include all specifications and details in its drawings and contract administration ensures all these details are followed. From an architectural standpoint, contract administration is not a new concept. However, contract administration for acoustical design has only recently become part of the mix.

In the past, acoustical engineers would only provide the design, while architects (in conjunction with the mechanical engineers and other team members) managed the contract administration. Whenever room acoustic questions would arise post-construction, acoustical engineers would be unable to provide immediate answers to the problem because they were not part of the construction modification process. Additionally, acoustical designs are increasingly more complicated and application-specific. As the complexity increases, most engineers and architects do not have the expertise to understand all the details to make the correct modifications to acoustical designs.

As a result, most acoustical firms are seeing the benefits of assigning a specialist to oversee contract administration. There is great value in having a single person oversee the design’s implementation. This individual is dedicated to ensuring design ideas are realized, and devoted to catching contract administration issues. This person should have a solid understanding of the design and its intended integration so he or she can make executive decisions on the spot to modify the plan, while still achieving the original acoustical goal. It should also be noted every project can be a learning opportunity because what did not work in one building still yields tremendous learnings for future projects.

No matter how thoughtful the original design, the reality of site conditions may not always be conducive to the plan and modifications required. Whether the design does not suit the conditions onsite, or the contractor requests modifications, the contract administrator takes the design intent and distills it to figure out how to make the changes work for the conditions. There are always two questions to answer: what should be done, and what can be done. The answers may differ greatly and help identify contractors will be amenable to doing when considering budgets and timelines.

Educating contractors
With any construction project, time is of the essence. When the deadline is approaching and there is plenty of work to be done, some contractors may be faced with the need to make executive decisions based on what they know to complete the project on time. Unfortunately, due to a lack of understanding about acoustics, a seemingly small and quick design change may have a big impact on the final acoustical outcome. For this reason, one of the most important roles of a contract administrator is education.First, it is important to note that on the jobsite there are various terms and treatments with which contractors might not be fully familiar—such as acoustic door seals or vibration isolation. The contract administrator can translate the terms and provide information on how these treatments can be used to create an acoustically sound building

acoustics_IMG_2707-shot with John and Kiyoshi
John O’Keefe and Kiyoshi Kuroiwa (this article’s authors) are next to a scale model used to design performance spaces, one of the many project types that can benefit from acoustical contract administration services. Photos courtesy Aercoustics Engineering Ltd

Second, there are a multitude of misconceptions about acoustics. The contract administrator can clear up confusion and ensure all parties are aware of how a design change will have an impact on acoustics. A common myth is glass fibre in walls absorb sound. However, glass fibre is not the agent that absorbs the sound. Rather, it is the enabler in the wall to help block out the sound, allowing the wall to have a better acoustical performance.

This is just one of many misconceptions that can lead acoustical plans astray. Having a contract administer available to answer contractor questions will ensure the right directions are relayed to the subcontracted tradespeople working on a project. By providing both expertise and education, the goal is to help contractors understand the importance of acoustics and how changes to the design may impede the acoustic goal. Compromised acoustics ultimately end up being costlier, so preventing issues before they happen is key.

Working with you not against you
During one of the first site visits, the contract administrator should sit down with the contractors and heads of trades, including drywall, mechanical, and masonry. The meeting should walk everyone through the design and identify where acoustics can be impacted. This includes discussing what can be seen in the design, and what is not as obvious—aspects like conduits in walls are not always visible on the drawings.

While most contractors understand conduits need to be run in the wall, they do not take into account the acoustical reasoning of how to run an electrical conduit so it does not affect the wall’s acoustical separation. The separation is solid when there are two one-sided walls; but this acoustical separation will be lost as soon as a conduit is placed across two studs. To make a good acoustic wall, the design should have one wall move but not the other. This is because once a pipe is placed in between and screwed tight, both walls will move together and the acoustic benefit is lost. If the construction crew is aware of this beforehand, or if a contract administrator catches it during construction, potential problems can be avoided. Once the walls are covered, they will need to be opened up to uncover any issues, leading to the potential that elements will need to be rebuilt.

This consideration is particularly important in condominiums. According to the Ontario Building Code (OBC), they have to satisfy a sound transmission class (STC) rating of 50. By implementing contract administration throughout the project, a contractor can ensure the minimum requirement is met and nothing needs to be redone once the building is occupied.

Most contractors take pride in their work and strive to ensure buildings are solid. Acousticians want portions of the building to be flexible, and this needs to be communicated to an entire project team. However, this should not be perceived as a battle between the various parties involved in a construction project. It needs to be a collaborative effort whereby working together, both parties may find a better way to implement the design and reach the acoustical goal.

From paper to reality
In order to have an acoustically sound building, it is imperative the various treatments be outlined in the contract. Contract administrators can only administer what is in the contract. By having a detailed plan including the acoustical treatments, it will help make certain the intended vision is realized.

For example, when referring to vibration isolation, the contract administrator will not only watch to ensure a contractor uses 25- or 51-mm (1- or 2-in.) springs, they also need to ensure the load on the spring is adequate to ensure it works properly. A spring with a 45.5-kg (100-lb) rated load, being loaded with only 13.6 kg (30 lb), would not be appropriate. However, a spring loaded at its rated load would provide the maximum benefit.

acoustics_Transformer
This transformer has been installed with a thin neoprene pad instead of the required spring vibration isolators, allowing vibration to pass into the structure, and enabling it to be heard in other parts of the building.

Architects, contractors, tradespeople, and building owners should consider the following three tips regarding contract administration.

1. Write it down: If an acoustically sound building is the goal, everything needs to be outlined in the contract. It is difficult to administer a project and make recommendations if it is not included in the initial scope or budget. Suggesting additional work to facilitate good acoustics will require an increased budget, and possibly delay a project.

2. Trust and understand the acoustical consultant: Everyone involved in a project has an area of expertise. Avoid misconceptions of what acoustics involves, and take advantage of any tutorials offered to learn the basics in order to ensure the entire vision is achieved.

3. It is a two-way relationship: With so many people responsible for completing a construction project, pressing timelines, and limited budget, it is imperative to know where to give and where to take. The design team, contractor, and contract administrator must work together to understand all points of view to find a solution to any issues.

Conclusion
Ultimately, acousticians strive to have someone walk into a building and have no idea an acoustician has been there. Success is having acoustics completely integrated into the design of the building so its effects can be enjoyed but not seen. This cannot be accomplished by acousticians alone. It requires significant collaboration between the architects, contractors, engineers, designers, and contract administrators, as well as building owners, to yield a finished product satisfactory to everyone involved.

 

John O'Keefe HeadshotJohn O’Keefe, M.Sc., P.Eng., FIOA, principal with Toronto’s Aercoustics Engineering Limited, is regarded as one of Canada’s foremost architectural acousticians. He is responsible for the acoustic design of many performing arts centres, such as Vancouver’s Orpheum and Queen Elizabeth Theatre, the Esplanade Arts and Heritage Centre in Medicine Hat, Alberta, and Toronto’s Princess of Wales Theatre. O’Keefe can be contacted by e-mail at johno@aercoustics.com.

 

Kiyoshi Kuroiwa HeadshotKiyoshi Kuroiwa, B.A.Sc., P.Eng, created and leads Aercoustics’ contract administration department. He is responsible for the acoustic design and contract administration of architectural projects such as the Aga Khan Museum and Ismaili Centre in Toronto, Simon Fraser University School for the Contemporary Arts in Vancouver, and Mount Allison University Purdy Crawford Teaching Centre in Sackville, New Brunswick. Kuroiwa has applied his experience playing piano and percussion in orchestras to the acoustical design of projects. He can be reached at kiyoshik@aercoustics.com.

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2 comments on “Sound advice on contract administration for acoustics”

  1. Good article. It’s hard to find this kind of commentary.

    I have a question however.
    -What if the acoustics for a room are not acceptable.
    a)how do you prove this?
    b)is this a deficiency?

    thx for your insight!

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