If the threshold is set to -10 and the criterion (100% level) is 85dB, the any sound below 75dB will not be added to the percentage dose figure. This would normally be set to 0, -5 or -10 and means the level below the 100% point where sound is counted towards the total %Dose. There is another element to % Dose, which is the cut-off point at which the dose is accumulated. Relationship between %Dose and Time with an Leq of 85dBA Noise Exposure Limits (Criterion Level = 85dB) The following tables show the relationship between the exchange rate, the criterion level and the noise exposure limits The effect of different Exchange Rate and Criterion Noise Exposure Limits (Criterion Level = 80dB) This means that the percentage level will change more slowly in respect of a changing sound exposure level. In some countries, the exchange rate is changed to 4,5 or sometimes even 6. ![]() This number is called the exchange rate.ĭoubling the exposure time doubles the Dose, and halving the exposure time halves the Dose given the same sound level. ![]() Similarly, if the sound level decreases by 3dB, the Dose will halve for the same exposure time. The tables below give examples of how DOSE is related to exposure time and Lex (Lep’d) (assuming 100% Dose = 85dBA for 8 hours.) Effect of changing SPL Lp (dBA)Įffect of changing Exposure Time Lp (dBA)Įffect of changing SPL and Exposure Time Lp (dBA)Įach time the sound level increases by 3dB, the Dose doubles given the same exposure time. Learn more about Dose - Noise at Work Training Course ![]() 100% Dose = 90dBA for 8 hours may also be specified. In other countries, Dose may be specified with a different criterion i.e. It is best described with the following statement:ġ00% Dose (or 100 points) = 85dBA for 8 hours. Noise – What is Dose and how is it calculated? In acoustics, what is noise Dose, how is it calculated and what is it used for?ĭose is a measure of noise exposure and is directly related to Lex, in the UK Dose is also described as the HSE ‘Points’ system.
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