730/730-IS Dosimeter Manual
B-2
Calibration
Adjustment of the system so that the measured sound level agrees with a reference sound source.
Calibration Check
A check for variations between the measured level and a reference level—no adjustment is made to the system.
Criterion Duration
The time required for a continually applied sound of the selected criterion level to produce a dose of 100%.
Criterion Duration is 8 hours by the standard for dosimeters.
Example: If the Criterion Level = 90 dB and the Criterion Duration is 8 hours, then a sound level of 90 dB for 8 hours
will produce a 100% Dose. See also
Criterion Level
The level of a sound, expressed in dB, which will produce a dose of 100% if continually applied for the criterion
time. The current OSHA criterion level is 90 dB.
Criterion Sound Exposure
Criterion Sound Exposure is the product of the Criterion Duration and the mean square sound pressure associated
with the Criterion Sound Level adjusted for the Exchange Rate. It is expressed in Pascal-squared seconds (Pa
2
s) and
Pascal-squared hours (Pa
2
h) when the exchange rate is 3 dB and “q” is the Exchange Rate Factor. Standard: ANSI
S1.25 See also
Daily Personal Noise Exposure (L
EP,d
)
The level, expressed in dB, of a constant sound over a specified normalization time period (T
n
= 8 hours) that
contains the same energy as the actual (unsteady) sound measured over a stated measurement period (T
2
– T
1
).
The measurement period is generally shorter, so the actual noise exposure is spread out, or normalized, over the
normalization time period. On the dosimeters, the normalization period is the Criterion Duration, and the
measurement period is the run time. For example, a measured L
eq
of 86 dB at a run time of 4 hours will produce an
L
EP,d
or L
EX
,8h of 83 dB at a normalization time of 8 hours.
OR
Example Application: The Criterion Duration is 8 hours, the specific period is 4 hours, and the average level during
the 4 hours is 86 dB. Then the L
EP,d
= 83 dB.
L
eq
= frequency weighted (A, C, or Z), equivalent-continuous sound pressure level in dB
T
n
= normalization period or Criterion Duration (8 hours)
T
2
– T
1
= measurement period or Run Time
