Sound
Sound intensity is measured in decibels (dB); the unit A-weighted dB (dBA) is used to indicate how humans hear a sound. Zero dBA is considered the point at which a person begins to hear sound. A soft whisper at 3 feet equals around 30 dBA, whereas a chainsaw can reach 110 dBA or more at operating distance [Ron Chepesiuk, 2005].
Mark Stephenson, (2005) defines hazardous noise as sound that exceeds the time weighted average of 85 dBA, meaning the average noise exposure measured over a typical eight-hour work day. Other measures and definitions are used for other purposes. For example, “sound exposure level” accounts for variations in sound from moment to moment, while “equivalent sound level” determines the value of a steady sound with the same dBA sound energy as that contained in a time varying sound. [Ron Chepesiuk, 2005].
In terms of acoustics, noise was defined by Miriam C. Daum in 1988 as ‘extra’ sound of greater than usual volume. Often the extra sound is unwanted so activities are often described as being “noisy”. As a result noise can be defined as “unwanted sound” [Miriam C. Daum, 1988]. Daphne Gloag (1980) outlined that precisely what constitutes “annoyance” in response to noise was a problem. The US Environmental Protection Agency based its recommendations specifically on interference with speech and also on complaints; however Gloag felt that annoyance should be taken to include feelings of “bother,” interference with activities, and minor psychosomatic symptoms such as headaches, tiredness, and irritability. However annoyance is defined, there is great individual variation, and clearly it does not depend only on the physical feature of the noise; the nature of the source, the circumstances, and the characteristics and attitude of the individual are all important. Gloag (1980) outlined that preventable or unnecessary noises and those that are meaningful tend to be the most disturbing; while a helpful attitude by those concerned may reduce annoyance.
Sound Sound intensity is measured in decibels (dB); the unit A-weighted dB (dBA) is used to indicate how humans hear a sound. Zero dBA is considered the point at which a person begins to hear sound. A soft whisper at 3 feet equals around 30 dBA, whereas a chainsaw can reach 110 dBA or more at operating distance [Ron Chepesiuk, 2005]. Mark Stephenson, (2005) defines hazardous noise as sound that exceeds the time weighted average of 85 dBA, meaning the average noise exposure measured over a typical eight-hour work day. Other measures and definitions are used for other purposes. For example, “sound exposure level” accounts for variations in sound from moment to moment, while “equivalent sound level” determines the value of a steady sound with the same dBA sound energy as that contained in a time varying sound. [Ron Chepesiuk, 2005]. In terms of acoustics, noise was defined by Miriam C. Daum in 1988 as ‘extra’ sound of greater than usual volume. Often the extra sound is unwanted so activities are often described as being “noisy”. As a result noise can be defined as “unwanted sound” [Miriam C. Daum, 1988]. Daphne Gloag (1980) outlined that precisely what constitutes “annoyance” in response to noise was a problem. The US Environmental Protection Agency based its recommendations specifically on interference with speech and also on complaints; however Gloag felt that annoyance should be taken to include feelings of “bother,” interference with activities, and minor psychosomatic symptoms such as headaches, tiredness, and irritability. However annoyance is defined, there is great individual variation, and clearly it does not depend only on the physical feature of the noise; the nature of the source, the circumstances, and the characteristics and attitude of the individual are all important. Gloag (1980) outlined that preventable or unnecessary noises and those that are meaningful tend to be the most disturbing; while a helpful attitude by those concerned may reduce annoyance.
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