There’s nothing more annoying than trying to get things done in a noisy environment. Whether you work in healthcare, education, government or the corporate sector, preventing noise bleed from room to room is an important factor for the quality of your workplace.

Regardless of industry, the question of acoustics comes up in every project we work on and knowing what you need can have a big impact in the design and development of your project as well as the happiness and efficiency of your employees when the final space is delivered.

Like all things DIRTT, acoustics should be talked about early. If you have specific code requirements, we’ll work with your team to meet those specifications. But for non-regulated environments, how do you know what you need? What should be in the walls and what shouldn’t be? What about the ceiling and sound transfer through the plenum?

Let’s unpack a few definitions and construction terms to help you determine what your building needs.

Construction for Privacy(DIRTT constructions includes at least a single layer of recycled denim batt insulation in wall assemblies, shown in this exam patient room mockup in DIRTT’s Calgary HQ)

To understand acoustics in construction we need to define two things, Sound Transmission Class (STC) and speech privacy.

Sound Transmission Class (STC) is a value indicating the sound transmission loss through a building partition or element. STC is based on laboratory testing of sound passing through walls and other structures; the higher the STC value, the more sound a building partition or wall will block.

Speech privacy, on the other hand, is a function of two factors; the background noise level in the receiving space (i.e. people talking, sound from a TV, etc.) and the acoustic separation between spaces expressed as STC. The combination of these two create the level of speech privacy within a space.

Here are common STC values in construction:


Sometimes it’s OK for some sound to bleed from room to room. However, if you’re working somewhere with specific code requirements, such as a hospital, it may be necessary to ensure the speech cannot be understood in other rooms in line with regulating bodies like HHS, HIPAA and FGI that provide specific guidelines

A minimum of 35 CAC (Ceiling Attenuation Class) or higher is suggested for most commercial applications. For most healthcare applications, 40 CAC is the minimum. Your architect or an acoustical engineer will help with defining those specific requirements,

Acoustical Management

(Evergreen Hospital selected DIRTT for this in-patient floor after careful consideration of acoustical performance. After extensive field-testing by an acoustical engineer, they determined the DIRTT partitions exceeded performance and provided better sound isolation compared to conventionally constructed walls.)

If increased speech privacy and STC are required within a space, conventional construction and DIRTT prefab construction take the same approach.

At Accelerate Built Environments, we take a holistic approach to acoustical management. It’s the walls, yes. But it’s also the ceiling, the floors, doors, gaskets and all the areas where materials connect with one another. Your walls can be incredibly sound-proof, but if we don’t address sound transfer where those walls connect to the ceiling or the rest of the building, we’ve missed the point. So, we look at everything as a whole and make sure it adds up.

When it comes to sound attenuation, solid walls increase in STC with increased mass and air spaces, where possible. We always provide at least a single layer of recycled cotton-denim batt insulation but can make additional enhancements.

We address Ceiling Attenuation Class (CAC) ratings for acoustic tile and drywall assemblies. The ceiling tiles must have a CAC rating that corresponds to the STC of the wall.

But we’re not done yet, we’ll also look at the mechanical, electrical and plumbing (MEP) equipment layouts above the ceiling to help determine if added insulation or barriers will be required. We’ll work with the architect and engineer to help determine if insulated acoustical boots are required so that the design and location of these items can be addressed during the design phase. Whether designing conventional or pre-fab spaces, architects will take into account that sound not only passes through walls, but through ceilings as well.

Privacy with Glass

(For this private equity firm, we used DIRTT’s “Evil Twin” double-pane laminated glass to provide a high level of acoustic performance between a loud break room and employees’ open office workspace directly adjacent.)

If you’re incorporating glass partitions into the design of your environment, added care should be taken to ensure appropriate levels of acoustic performance. Glass walls can also be designed to meet increased STC ratings. While our baseline of 10mm clear tempered glass provides a good sound barrier, we can also use laminated glass and even double paned walls to further dial-up acoustic performance

Here’s a quick look at how glass typically performs acoustically.

Performance STC of glass:

  • 6mm tempered glass – 30 STC
  • 10 mm tempered glass – 31 STC
  • 10mm laminated glass – 33 STC
  • 6mm laminated PVB glass (COM) – 35 STC
  • 10mm laminated PVB glass (COM) – 38 STC
  • Double pane 10mm laminated glass – 42 STC

*Please note that the above are all approximate STC values.

While there are unique considerations dependent upon working with glass, we’ve perfected the practice to account for industry types and individual preferences.

When building with STC or acoustical management in mind, Accelerate Built Environment accounts for walls, ceilings, glass partitions and doors to help you meet standards and create an acoustically-conscious work environment.

And there you have it! You’ve been introduced to the world of acoustics in construction. While we’ve scratched the service of sound’s influence in prefab interior construction, there are additional considerations that may shape your decision-making when it comes to building your next project.

Luckily, our experts are all trained in educating customers, architects, designers and construction managers on your options when designing a prefab project. To learn more about how Accelerate can help provide an ideal workplace with your next project, contact us and we’ll put you in touch with one of our friendly experts.