Noise can be defined as “unwanted sound”; audible acoustic energy that adversely affects the physiological and/or psychological well-being of people or which disturbs or impairs the convenience or peace of any person (affecting their quality of life). One can generalize by saying that sound becomes unwanted when it:
- Hinders speech communication;
- Impedes the thinking process or interferes with concentration (a receiver feels annoyance with the sound);
- Obstructs activities (work, leisure, and sleeping); and
- Presents a health risk.
However, it is important to remember that whether a given sound is “noise” depends on the listener or hearer. A person playing loud rock music in their living room hears only music, though his next-door neighbor hears nothing but noise. However, noise does not need to be loud to be considered “disturbing”. One can refer to a dripping tap in the quiet of the night or the irritating “thump-thump” of the music from a neighboring house at night when one would prefer to sleep.
Only considering the “intensity” of a sound (or noise) level (the sound pressure level), some people may become annoyed without hearing any noise (perceived impacts), whereas others may not even be reporting noise to be a concern, even when subjected to very high levels. How a receiver may perceive a noise impact, or determine the “severity” of a noise annoyance include:
- The sound pressure level (see also the image below) and the background sound levels (the ambient sound level / residual noise level) the receptor is used to;
- The manner in which the receptor can control the noise (helplessness);
- The time, unpredictability, frequency distribution, duration, and intensity of the noise (see typical sound levels associated with various activities or equipment);
- The physiological and health state of the receptor; and
- The attitude of the receptor about the noise source.
National and Provincial Regulations
As “noise” is perceived differently by different people, there are legislative guidelines that can be used in South Africa to assess whether a certain sound can be defined as noise. This includes:
- The National Noise Control Regulations (Government Notice Regulation (“GNR”) 154 as published in Government Gazette 13717, dated January 1992) – valid in Limpopo, Northern Cape, Eastern Cape (proposed regulations were published under GN181/PG824/20011210) and KwaZulu Natal – where a disturbing noise is the noise level where the zone sound level is exceeded, or, if a zone sound level has not been designated, the level that exceeds the ambient sound level with more than 7 dBA;
- Free State Noise Control Regulations (Provincial Notice 24/Provincial Gazette 35 of 24 April 1998) – where a disturbing noise is the noise level that exceeds the ambient sound level with more than 5 dBA;
- Gauteng Noise Control Regulations (General Notice 5479/Provincial Gazette 75 of 20 August 1999) – where a disturbing noise is the noise level that causes the ambient noise level to rise above the designated zone level, or, if no zone level has been designated, the typical rating level for ambient noise in districts as defined in Table 2 of SANS 10103:2008; and
- Western Cape Noise Control Regulations (Provincial Notice 200 of 20 June 2013) – where a disturbing noise is the noise that (a) exceeds the rating level with 7 dBA; (b) exceeds the residual noise level (the ambient sound level) where the residual noise level is higher than the rating level; (c) exceeds the residual noise level by 3 dBA where the residual noise level is lower than the rating level; or (d) exceeds the level specified in Annex B of SANS 10103 (in the case of a low-frequency noise).
Each of these regulations is relevant for proposed projects to be developed within the various provincial areas, with the key points discussed in separate posts. These regulations set the legislative background, allowing a qualitative means of defining a “disturbing noise”, with the process of defining a “disturbing noise” roughly by:
- The defining of the acceptable sound levels (or a zone sound level or rating level): There are two accepted procedures to define this, namely the measurement of ambient sound levels using a sound level meter (considering the developmental character), or obtaining a zone sound level as defined by SANS 10103:2008 (or as assigned by the Provincial, Metropolitan or local Municipality).
- The measurement of the noise level using an accepted protocol (or the calculation of the potential noise level if measurements are difficult) near the source of noise, or near a receptor complaining about a potentially annoying or disturbing noise;
- Using the correct noise control regulation to assess the change in either ambient sound level, or how an intruding noise influences the zone sound level.
Local Municipal Bylaws and Noise Policies
When the local municipality can comply with the relevant noise control regulations, they could have their own noise control officers (or similar), their own bylaws and/or noise policies. The approach is generally to define appropriate noise level standards for various land uses. The bylaws or noise policy may possibly use the following noise levels for a residential area:
- 55 dBA for the day-time period (06h00 – 22h00); and
- 45 dBA for the night-time period (22h00 – 06h00).
These noise “thresholds” may not be exceeded on a continuous basis for example in Gauteng province.
As an example: A person may be hooting in the road in front of your residence, and, while it may be very annoying and significantly higher than the “threshold”, the noise is not continuous and may not violate the law. However, your neighbor may select to play their music for a few hours (or operate a power generator) for a few hours, activities that does violate the bylaw or policy.
Way forward
These criteria are used during the investigation of a noise complaint as well as for a noise impact assessment. Any mistakes in any of these steps could result in a project proceeding but:
- Potentially disturbing noise is registered and expensive noise pollution control measures are required; or
- Noise levels were over-calculated with the project developer unnecessarily implementing expensive noise pollution control measures.
Should you have any questions you are welcome to contact EARES.