Casella-cel CEL-281 Manual do Utilizador descarregar pdf (Página 26)

At levels below the First Action Level (1.0 Pa 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

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

EP,d

dB(A)

%Dose

900045

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 , D, and L for a normalised

eight hour working day with 90 dB equivalent to 100% dose

Introduction_

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Casella-cel CEL-281 Manual do Utilizador Página 26