Casella CEL-352 dBadge Manuale delle Istruzioni Scaricare il pdf (Pagina 34)

Casella CEL-35X dBadge Users Handbook – Page 34

LAVG

This is a parameter used in OSHA measurements. It is the

average sound level over the measurement period (equivalent to

Leq). Normally the term is used when the exchange rate Q is some

value other than 3, such as for measurements used for the OSHA

Hearing Conservation Amendment with Q=5. A Threshold value is

used during the calculation of LAVG, where any levels below the

threshold are not included. For example, assume the threshold

level is set to 80dB and the exchange rate is 5dB (Q = 5). If a one

hour measurement was taken in an environment where the noise

levels vary between 50 and 70dB, the sound level would never

exceed the Threshold so the instrument would record no value for

the LAVG. However, if the sound level exceeds the 80dB

Threshold for only a few seconds, only these seconds will

contribute to the LAVG, giving a level of around 40dB, which is

much lower than the actual ambient sound levels in the measured

environment.

LCpeak

The peak C-weighted sound level.

LEP,d

This is the daily personal noise exposure defined by ISO 1999. It is

the LAeq normalised to an 8 hour Criterion Time, i.e. a standard

day. Assuming the noise level for the rest of the 8 hour reference

period is “quiet”, the LEP,d will be: lower than the Leq when the

measurement duration is less than 8 hours, equal to the Leq for a

measurement of 8 hours, higher than the Leq for measurements

longer than 8 hours. For example, if a noise measurement was

made for 4 hours and the LAeq value was 90dB(A), the LEP,d

value would be calculated to be 87dB(A) as the measurement

duration is half the 8 hour Criterion Time and the exchange rate is

3 dB.

LCeq

The C-weighted equivalent level is the level that would contain the

same amount of noise energy as in the actual noise, effectively

giving an average level over the measurement period. Following

the ISO procedures, doubling the energy results in a 3dB change

in the Leq. This is denoted by exchange rate Q=3.

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Casella CEL-352 dBadge Manuale delle Istruzioni Pagina 34