Casella CEL CEL-393 - Manual (Page 70)

15. After the delayed start has been reached, the first L 10 index
(calculated for the period between 6.00 and 7.00 am) may be
obtained by pressing 4M (sequence for L
10 ).
16. Press M to obtain the second L 10 sample.
17. Press M again to obtain subsequent samples.
If the instrument is collected on the day after the measurements were
taken, only the first 18 answers from the L
10 memory will be required.
The calculation of the full L 10 18 hour index is achieved by adding them
together arithmetically and then dividing the sum by 18.
If necessary, the period L eq , L max , L 50 , and L 90 answers may also be
accessed by keying in the relevant codes (1M, 0M, 5M, and 6M respec-
tively).
All results may be hand written on pre-printed report sheets (SP0884),
or if the CEL-393B with built in interface is used, they can be printed
automatically using the CEL-238, CEL-338 and CEL-438 Digital Proces-
sor/Printer.
Switch the instrument off when all relevant answers have been obtained.
6.3 Event Mode
This mode is used for measuring peak air over-pressures that occur at
comparatively random intervals in sensitive locations, where possible
claims for noise nuisance may occur.
Requirement:
Monitor peak levels around a site where quarrying operations and
blasting take place.
Proceed as follows.
/66. 393 Handbook