Casella CEL CEL-450 User Manual
Page 8
The broadband screen in Figure 1 shows one principal and four
subordinate parameters, where the principal parameter is a level as
identified below.
The following frequency weightings may be shown:
A-, C- and Z- (Linear) weighted.
The following time weightings and other identities may be shown.
S
Slow.
F
Fast.
I
Impulse.
pk
Peak.
mx
Maximum.
mn
Minimum.
eq
Equivalent continuous level.
AV
Average level.
Tm3
Taktmaximal 3 sek.
Tm5
Taktmaximal 5 sek.
EP,v
L
eq
based noise dose normalised to a user
specified period of hours and minutes.
When the period is specified as 8 hours, this
measurement unit will be shown as EP,d.
TWAv
Time Weighted Average is the normalised time
averaged sound pressure level with the selected
frequency and time weighting that represents
the total average of a persons workplace noise
exposure averaged over a user specified period
of hours and minutes.
This unit of measurement is specified in the
USA: OSHA standard 1910-95 published in 1983.
When the period is specified as 8 hours, this
measurement unit will be shown as TWA.
N
Percentile sound level.
AE
Sound exposure level.
HML
Calculated as L
Ceq
- L
Aeq
Introduction
Page 8 - CEL-450/490 Operators Handbook