Condominium managers and property managers often receive complaints from condo residents about noise. Managers must investigate and try to address the complaints. Mechanical noise issues can arise in any building, but mitigating them in modern wood structures can be more challenging.
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Complaints about noise caused by people in the building are covered by other articles. Here I will deal with complaints about mechanical equipment noise.
Identifying the noise source
Property managers are responsible for investigating noise complaints and attempting to resolve them. Before any noise issue can be mitigated, its source must first be identified. The troubleshooting process is straightforward:
This approach will identify the offending equipment that needs to be modified to reduce the noise. Resolving the issue typically requires the involvement of equipment maintenance personnel, and in some cases, the guidance of an acoustical consultant can be invaluable.
In most situations, the noise path from the equipment to the complainant’s apartment is structural — the vibration travels through the building’s framework, sometimes over considerable distances. The root cause is often improper installation of the equipment. To mitigate the problem, the offending equipment must be reinstalled with proper vibration isolation measures in place.
How much mechanical noise is acceptable?
Noise is a constant part of the environment; complete silence simply does not exist. Property managers often ask what level of noise within a dwelling can be considered “normal.”
The question of rating interior noise is complicated due to many interrelated factors.
Human factors.
Sensitivity to noise is highly subjective. Some individuals are disturbed by sounds that others perceive as minor or may not even notice.
Physical factors.
Sound is a complicated physical phenomenon. Sound has many characteristics that influence its annoyance levels to people. Some of the physical factors are:
What is the maximum noise level acceptable in a residential apartment?
The answer to this question is not as easy as it seems. As far as I know, no legislated requirements state Ontario's maximum permissible noise levels in dwellings.
Municipalities set the maximum permissible noise limits, usually addressing exterior noise levels. In Ontario, the MOE document NPC-300 guides the municipalities.
Toronto noise bylaw regulates outdoor noises. However, I have heard of Toronto noise bylaw officers using it for mechanical noises indoors. This is nonsensical, classifying noise levels at 50 dBA as acceptable.
Industry organizations provide guidelines for maximum noise levels. The most common in North America is ASHRAE. ASHRAE defines several criteria for rating noise levels. Consultants often use the ASHRAE recommendations to rate the acceptability of interior noise. The test must be done in accordance with ANSI/ASA Standard S12.72. However, this approach has a limitation:
World Health Organization (WHO) has noise guidelines based on ISO standards that are more stringent than ASHRAE.
This leaves much discretion to consultants on how to select and apply these guidelines.
The intrusiveness of noise.
Some consultants also use subjective descriptions of “intrusiveness” to assess noise annoyance. This definition probably originated in a textbook on acoustics.
Intrusiveness: The intrusiveness of noise mainly depends on its relative amplitude compared to the background noise at the receptor location. It is commonly considered that if the overall sound level is 1-3 dBA above the background, it is assessed subjectively as “insignificant”; 3-5 dBA above the background is assessed as being subjectively “noticeable”; if the overall sound level is 5-10 dBA above the background, it is assessed subjectively as “significant.” It is also commonly accepted that a 10 dB increase in noise levels is subjectively equivalent to a doubling of sound levels for individuals. For an extraneous noise to be inaudible, it must be at least 10 dB lower than the background noise.
Summary – dealing with mechanical noise complaints.
With sufficient effort, it is usually possible to identify the source of a mechanical noise problem. However, mitigation can be costly. Property managers are often reluctant to address low-level noise and instead seek guidance on what constitutes an “acceptable” noise level. Acoustical consultants can provide recommendations, but because the issue is complex and clear standards are often lacking, those recommendations are sometimes open to challenge or dispute.
For readers interested in more in-depth treatment of noise-related issues in buildings, visit this British document.
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