Casella CEL CEL-35X dBadge - Manual (Page 37)

Casella CEL-35X dBadge Users Handbook – Page 37
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.
Peak
The maximum level in dB reached by the sound pressure at any
instant during a measurement period. With the dBadge, Peak is
measured with either C, Z or A weighting. It is the true peak level of