Noise dose meter

Two basic instruments are used to assess the workplace for noise the soimd pressure level (SPL) meter, and the noise dose meter (NDM). The SPL meter in normal mode automatically adds the dB levels at various frequencies to give a total dB level. This is when it is in dBlin (dB hnear) setting. Many SPL meters have either a built-in or add-on octave band analyser . This allows you to measure the SPL at a range of frequencies, each at the centre of an octave band. Just as in music, going up one octave from a particular frequency means doubling the frequency. 

Noise monitoring is usually located in the HASP as part of the monitoring program. Noise monitoring should be performed in accordance with acceptable practices. Typically, noise levels are monitored in the field with either a Type I or Type II sound level meter (SLM). Noise dosimeter readings can also be obtained to determine the percent (%) noise dose. Noise levels and % doses measured are then compared to limits listed in OSHA standard 29 CFR 1910.95, Hearing Conservation [3]. 

Dose-Response Relationship The systematic relationship between the dose (or effective concentration) of a drug or xenobiotic and die magnitude (or intensity) of the response it elicits. Dosimeter (dose meter) An instrument which measures the accumulated energy to which one may be exposed, i.e., noise, radiation, etc. 

Noise. Technical differences exist between personal noise dosimeters and high accuracy sound level meters and these may alter the usual preference for personal monitors. But it is exposure to noise rather than general room noise that must be estimated for comparison with noise exposure criteria, the logarithmic expression and alternative means of summation (3 vs 5 db doubling) compHcate statistics. Exposure criteria for both dose and peak exposure must be evaluated, and space and time variabiUty of noise intensity can be immense. 

Besides being exposed to ambient noise, carwash workers studied also work with the noise emitted by the water pump and the vacuum cleaner. Therefore, an analysis was performed for this risk, which happened in a simplified way due to the short time data collection and also the inability to calculate the doses of each noise. Measurements were made on two cars that were washed one by each employee and not necessarily began their washing at the same instant. The equipment used was INSTREFTHERM decibel meter and measured the noise when the pump was turned on, when the vacuum was on and when both machines were turned off. 

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