Casella CEL CEL-281 - Manual (Page 28)

Results obtained by various researchers indicate that when the risk of
hearing damage is being considered, less emphasis need be placed on
the energy contained in higher noise levels.
When necessary, these findings can be incorporated quite simply into
the noise dose calculation by applying a different Exchange Rate, for
example in some of their requirements, the U.S.A. Occupational Health
and Safety Authority (OSHA) specify Q = 5.
Figure 2 illustrates the relationship between the exchange rate Q, hear-
ing damage risk, and the number of dB found to increase the risk.
In the CEL-281, results are calculated and stored for up to four different
exchange rates, Q = 3, 4, 5, and 6.
Figure 2: Relationship between Q and the risk of hearing loss
Change in
Noise Level
Risk of
increase
Hearing Loss
dB
found to
7
6
5
4
3
2
1
1 x Risk 2 x Risk
Q = 3
Q = 4
Q = 5
Q = 6
(Equal Energy)
910005
Q = Slope
Q ∝ 1
Risk
Page 20 - CEL-281 Operator's Handbook
Introduction_