Casella CEL CEL-281 - Manual (Page 26)

At levels below the First Action Level (1.0 Pa
2
h - equivalent to 85 dB(A)
for 8 hours) "reasonably practicable" noise reductions should be made.
Between the First and Second Action Levels (3.2 Pa
2
h - 90 dB(A) for 8
hours) noise assessments must be made, records kept, details given to
employees, and hearing protection issued to those who ask for it. Above
the Second and also at or above the Peak Action Level (200 Pa - 140 dB
for any period), hearing protection measures must be enforced by the
employer.
2.2.2 Criterion Level
Many European sound exposure standards specify 90 dB(A) for eight
hours as the Criterion Level used to define 100% Noise Dose.
However, other noise dose legislation may require a different criterion
level for the value of a 100 % noise dose, for example some U.S.A.
Department of Defense (DOD) Standards specify 84 dB, i.e. an expo-
sure of 84 dB for eight hours is equivalent to 100% noise dose.
In the CEL-281, results can be calculated and displayed for up to six dif-
ferent criterion levels: 70 dB, 75 dB, 80 dB, 84 dB, 85 dB, and 90 dB.
The instrument will accept the selection only of valid criterion levels, i.e.
levels that are equal to or greater than the Threshold Levels selected.
Refer to Table 1 for valid pairs of levels, and to Section 2.2.3 for an expla-
nation of Threshold Level.
Pa h
2
L
EP,d
dB(A)
E
D %Dose
900045
A
80 82 84 86 88 90 92 94 96 98 100 102 104 106
0.3 0.4 0.5 0.6 0.8 1.0 2.0 3.0 4.0 5.0 6.0 8.0 10 20 30 40 50 60 80 100
10 20 30 40 50 60 80 100 200 300 400 600 800 1000 2000 3000 4000
1st Action
Level 1.0
2nd Action
Level 3.2
Peak Action Level 200 Pa
Triggers Overload Indication
Figure 1: Relationship between E A , D, and L EP,d for a normalised
eight hour working day with 90 dB equivalent to 100% dose
Page 18 - CEL-281 Operator's Handbook
Introduction_