Pulsar 22 - Page 55

dosemeter User Manual
Page 55
L
EP,d
The L
EP,d
is the average of the measured L
eq
over an eight hour period. The L
EP,d
will be
lower than the L
eq
when the measurement duration is less than eight hours, equal to
the L
eq
for a measurement of eight hours, and higher than the L
eq
for measurements
over eight hours.
For example:
If a noise measurement was made for 4 hours and the L
Aeq
value was 90dB(A), the L
EP,d
value would be calculated to be 87dB(A) as the measurement duration is half the
Criterion Time of 8 hours and the exchange rate is 3dB.
L
EX,8h
Under the EU Physical Agents (Noise) Directive which was introduced in member states
of the EU in February 2006, the terminology for the Daily Personal Noise Level or L
EP,d
has been changed to be L
EX,8h
. The calculation is the same and the data is calculated
from the LAeq and Measurement Duration in the same way as for L
EP,d
.
TWA
The Time Weighted Average is the average of the measured L
AVG
over an eight hour
period. The TWA will be lower than the L
AVG
when the measurement duration is less
than eight hours, equal to the L
AVG
for a measurement of eight hours, and higher than
the L
AVG
for measurements over eight hours.
% Dose
A percentage of a fixed dose value based on the criterion level and criterion time. The
criterion level and time are set by local standards.
For example, some Regulations may mandate the use of 85dB for 8 hours as the limit
for a daily noise exposure. If the noise level was a constant 85dB for 8 hours, this
would generate a % Dose of 100%.
Estimated Dose
Estimates the % dose (described above) that would have been received by the wearer
if the average level measured had existed for the period defined by the criterion time.
For example, if for a 4 hour measurement the % Dose was 50%, the Estimated Dose
would be 100% for the 8 hours of the Criterion Time.
Exposure (Pa
2
s, Pa hr)
The noise exposure expressed in linear terms rather than using the logarithmic dB unit
or % dose. Expressed in Pascal squared hours (Pa hr) or Pascal squared seconds (Pa s).