Today’s residential noise levels demand new standards of construction to reduce noise. With the recent construction booms of condominiums, privacy between units is a significant issue. People would like their apartments to be quiet and free from noise intrusions, just like in a family home, but the reality is very different for condos. Noise transmission is the number one social problem in condos, largely due to building code standards that are barely minimal for an environment where people live in close proximity to each other. Unfortunately, builders put money into the appearance of a building but little into noise isolation. The words “luxury” or “high quality” are very often used to describe condominiums that only meet minimum noise code standards. The quality of the materials going into the buildings is highly limited regarding noise isolation resources.
The words “luxury” or “high quality” are very often used to describe condominiums that only meet minimum noise code standards.
Here at Acoustic Sonic Inc. we receive many calls each week asking for help with this issue and we love to assist in these situations, but many times there is little that can be done at this stage without significant cost and intrusion. Sound isolation issues are most effectively addressed before construction, during the design phase.
Outdoor noise such as traffic noise, night clubs, or construction noise are frequent. Additionally, interior noise sources such as those due to turbulent water flow traveling along the piping through rigid connections to walls and ceilings as well as vibrations caused by mechanical sources like elevators and mechanical rooms are very often felt as well. Even gyms close to apartments producing high level music and impact noise from heavy weights are a common issue.
Many cities and states have adopted standards for STC (Sound Transmission Class) and IIC (Impact Insulation Class) in multifamily households. Typical requirements include a minimum sound transmission loss for walls and floors between units. Cities and counties adopt a basic code and then make modifications to suit their needs. For example, an STC 50 and IIC 50 is the code required rating for some cities, with a minimum field test tested FSTC 45 and FIIC 45 are allowed. However, this does not necessarily mean that it yields acoustical privacy between units or that it represents a level of quality that guarantees owner satisfaction. In apartments with high prices, where the noise problem is too perceivable, other reasonable expectations of the buyer should be used as the basis for construction decisions.
The table below shows classification established by the U.S Department of Housing and Urban Development in the Guide to Airborne, Impact, and Structure Borne Noise Control in Multifamily Dwellings. Descriptive definitions of three grades of acoustic environments are given in order to ascribe criteria suitable to the wide range of urban developments.
| Transmitting Room | Receiving Room | Luxury Grade I STC | Average Grade II STC | Minimum Grade III STC | Luxury Grade I IIC | Average Grade II IIC | Minimum Grade III IIC |
| Bedroom | Bedroom | 55 | 52 | 48 | 55 | 52 | 48 |
| Living Room | Bedroom | 57 | 54 | 50 | 60 | 57 | 53 |
| Kitchen | Bedroom | 58 | 55 | 52 | 65 | 62 | 58 |
| Family Room | Bedroom | 60 | 56 | 52 | 65 | 62 | 58 |
| Corridor | Bedroom | 55 | 52 | 48 | 65 | 62 | 48 |
| Bedroom | Living Room | 57 | 54 | 50 | 55 | 52 | 48 |
| Living Room | Living Room | 55 | 52 | 48 | 55 | 52 | 48 |
| Kitchen | Living Room | 55 | 52 | 48 | 60 | 57 | 53 |
| Family Room | Living Room | 58 | 54 | 52 | 62 | 60 | 56 |
| Corridor | Living Room | 55 | 52 | 48 | 60 | 57 | 53 |
| Bedroom | Kitchen | 58 | 55 | 52 | 52 | 50 | 46 |
| Living Room | Kitchen | 55 | 52 | 48 | 55 | 52 | 48 |
| Kitchen | Kitchen | 52 | 50 | 46 | 55 | 52 | 48 |
| Bathroom | Kitchen | 55 | 52 | 48 | 55 | 52 | 48 |
| Family Room | Kitchen | 55 | 52 | 48 | 60 | 58 | 54 |
| Corridor | Kitchen | 50 | 48 | 46 | 55 | 52 | 48 |
| Bedroom | Family Room | 60 | 56 | 52 | 50 | 48 | 46 |
| Living Room | Family Room | 58 | 54 | 52 | 52 | 50 | 48 |
| Kitchen | Family Room | 55 | 52 | 48 | 55 | 52 | 50 |
| Bathroom | Bathroom | 52 | 50 | 48 | 52 | 50 | 48 |
| Corridor | Corridor | 50 | 48 | 46 | 50 | 48 | 46 |
People often ask us what is considered normal interior apartment noise. There are many ways to measure sound levels, but the most commonly used is dBA, which is based on intensity and on how the human ear responds to it. As an example, the acceptable noise level for bedrooms is 25-30 dBA while for living rooms 35 dBA is acceptable.
It’s important to understand that humans detect varying frequencies differently because our ears are less sensitive to low frequencies than they are to high frequencies. However, sometimes we have measured an “acceptable” 30 dBA in an apartment, yet the people there are still troubled by high structural noises or low frequencies that remain clearly perceived.
In future blogs we will talk about noise complaints and the solutions that we have attained for them over the course of our time as a business for over 20 years.
Edited by Alex Hikmat