Brüel & Kjær 2240 Guide De L'utilisateur page 15

The four sound level parameters are:
• L : The 'A' frequency-weighted and 'F' time-weighted sound pressure level. This parameter
AF
is always displayed when the instrument is switched on, even if you have not started a meas-
urement. It is an instantaneous value, which is mainly used to determine the approximate
sound levels in order to select the appropriate sound level range to measure.
Fig.2.1
L parameter displayed
AF
• L : The equivalent continuous, 'A' frequency-weighted sound pressure level. L
Aeq
ear average of all the varying sound pressure levels detected during a measurement. For a
number of international and national standards, it is the key parameter in determining annoy-
ance from environmental noise and assessing the risk of hearing deficiencies induced by expo-
sure to high sound levels at the work place. Note: L
Fig.2.2
L parameter displayed
Aeq
• L : The maximum 'A' frequency-weighted and 'F' time-weighted sound pressure level
AFmax
detected during a measurement. It is the maximum value of L
ment. It is often used in comparison with another parameter (for example: L
single noise event does not exceed a limit.
Fig.2.3
L parameter
AFmax
displayed
• L : The maximum 'C' frequency-weighted, peak sound pressure level detected during a
Cpeak
measurement. L
sound pressures of short durations at work places. Remember that peak levels can be very high
is used to assess risks of hearing deficiencies induced by very high
Cpeak
is not time-weighted.
Aeq
detected during a measure-
AF
Aeq
PART 1
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English
is a lin-
Aeq
) to ensure a