Environmental Noise Issues

Commercial and public facility managers or owners occasionally encounter situations involving objectionable noise outside of their facilities. These may relate to noise produced by neighbors adversely impacting the facility; may be the subject of complaints by neighbors in response to operations or changes at the facility; or complaints may be received from neighbors new to the setting. 

Unlike loud noise that affects facility employees and is regulated by OSHA, noise levels experienced by neighbors from adjacent or proximate facilities are not often of concern regarding adverse effects on hearing. Rather, these more often relate to quality of life or nuisance concerns and entail complaints such as sleep disturbance, communications interference, or general enjoyment of life or property. Compounding the subjective nature of what may constitute a nuisance to an individual or small group (note a simple definition of noise as “unwanted sound”), meeting local noise standards may pose several challenges.  A noise ordinance may not exist, or an ill-conceived ordinance may be unclear as to what the requirements actually are, or be unrealistically stringent (possibly having never been called into contention).

Absent local ordinances, and sometimes with (not all local ordinances contain numerical noise limits), sound level criteria such as those in The Noise Guidelines published by the U.S. Department of Housing and Urban Development, and the 1974 EPA Noise Document can be very useful in helping to define acceptable community noise levels. Both of these documents express acceptable criteria in terms of a combined day-night average sound level (L_DN) value.  The L_DN is a 24-hr. average noise level that includes a 10-decibel penalty added to the values measured between 10 pm and 7 am. For example, the EPA document references a 24-hr. L_DN value of 55 dBA as an acceptable value outdoors in residential areas among the values sited. Local ordinances will sometimes use this approach, and may include multiple L_DN values for different zoning designations, or different noise levels for different periods of the day. Issues such as impulse noise may or may not be covered, and noise-producing activities such as use of leaf blowers or equipment operation may be limited to certain times of the day or week or prohibited.

While noise measurement is often the response to complaints, measurements can be beneficial for other reasons. These include:

• Background levels prior to facility construction.  These pre-construction measurements may be compared to post-construction noise levels in order to confirm that facility operations have not resulted in significant impact on local environmental noise levels.
• Background levels prior to development encroaching upon the facility, to sort out facility contributions prior to contributions from later arrivals (though the issue of who arrived first may carry little weight when property line noise levels exceed an ordinance value). 
• Background levels on hand in the event new ordinances or changes in existing ordinances are proposed, so that potential impact of a proposed ordinance change on the facility can be assessed.
• Identifying opportunities for cost-effective noise reduction.

If making environmental noise measurements, check beforehand to ensure measurements will address any and all existing ordinance criteria. Inclusion of octave band measurements, even if not required by the ordinance, will often prove beneficial (as a type of noise fingerprint or in event controls are contemplated). For an example of a model noise ordinance, visit this page on the Quest Technologies Web site.

You may e-mail jfinney@workplacegroup.net or phone 336-931-0300 if you have any questions about this topic.