How to Measure the Acoustics of a Building: The Essentials You Need to Know
Monday, 09 September 2024
In the construction field, acoustics is a crucial factor for ensuring the comfort of occupants. But how do you accurately measure the acoustic performance of a building? This article reveals the main methods for quantifying acoustics, helping you understand the key indices that guarantee effective sound insulation.
First, to assess the acoustic performance of buildings, two types of indices are mainly used: those derived from laboratory tests (IIC/STC) and those obtained in real-world conditions on-site (AIIC/ASTC). Laboratory results are often higher due to controlled conditions. However, at AcoustiTECH, we prioritize on-site indices to offer product assembly solutions that best reflect real-world usage conditions.
On-Site Index
Impact noises (AIIC), such as footsteps or furniture movement, can be a real nuisance. Here's how they are quantified on-site:
The AIIC (Apparent Impact Insulation Class) is an index that evaluates the insulation of impact noises in a floor/ceiling assembly directly on-site. This test offers a more accurate representation of real-world construction by integrating the specificities and weaknesses of structures. It provides greater precision by accounting for indirect sound losses due to the construction methods used.
Airborne noises (ASTC), such as voices or music, are measured on-site by:
The ASTC (Apparent Sound Transmission Class), an index that measures the ability of an assembly, such as a wall or floor, to attenuate airborne sound transmission in real-world construction conditions. Unlike laboratory tests, ASTC reflects acoustic performance while considering the specificities and particularities of construction methods on-site.
A New Index
The HIIC (High Impact Insulation Class) is a new acoustic index that evaluates the performance of impact noise insulation in medium and high frequencies, directly related to the perceived acoustic comfort of an individual in their environment. The HIIC, therefore, measures the ability of a floor/ceiling assembly to attenuate impact noises most likely to cause acoustic complaints, such as high-heeled shoes or furniture being moved.
Standards
As for current acoustic standards for a floor/ceiling assembly in multi-story residential buildings, the National Building Code (NBC) requires the following minimum requirements: an STC index of 50 or an ASTC index of 47, with no minimum requirements for IIC and AIIC indices. However, it is recommended to have a minimum IIC index of 55 for better acoustic comfort.
Beware of Published Values
It's essential to be cautious about published acoustic values. As mentioned earlier, laboratory results (IIC/STC) are often higher than those obtained on-site (AIIC/ASTC) due to optimal laboratory conditions. For a realistic evaluation, always compare values in conditions similar to your project.
Moreover, some floor or acoustic membrane manufacturers may exploit the complexity of acoustics to mislead by publishing high values without detailing the product assembly or omitting whether the tests were conducted in the lab or on-site. Therefore, it's crucial to compare published values for similar test conditions.
Understanding acoustic indices is essential for choosing the right solutions and product assemblies for your building. The indices mentioned above help you effectively measure sound insulation, whether for impact or airborne noises. At AcoustiTECH, we are here to assist you in selecting the best acoustic assembly solutions for your projects to ensure the right product at the right place.Don't hesitate to contact us to discuss further!
Vincent Moreau
Co-owner
Executive Vice-President Sales
Innovation & Strategic Development
Ambassador of Sustainability
AcoustiTECH