TSI Quest EDGE EG-4P, Руководство пользователя

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B-4 The Edge Personal Noise Dosimeter Model EG-4P User Manual
Lavg (Average
Level) Lavg is the average sound level measured over the run time. This becomes a bit
confusing when thresholds are used. Any sound below the threshold is not
included in this average. Remember that sound is measured in the logarithmic
scale of decibels therefore the average cannot be computed by simply .adding the
levels and dividing by the number of samples. When averaging decibels, short
durations of high levels can significantly contribute to the average level. Example:
Assume the threshold is set to 80 dB and the Exchange Rate is 5 dB (the settings
of OSHA’s Hearing Conservation Amendment). Consider taking a one-hour noise
measurement in an office where the
A -weighted sound level was typically between
50 dB and 70 dB. If the sound level never exceeded the 80 dB threshold during the
one hour period, then the Lavg would not indicate any reading at all. If 80 dB was
exceeded for only a few seconds due to a telephone ringing near the instrument,
then only those seconds will contribute to the Lavg resulting in a level perhaps
around 40 dB (notably lower than the actual levels in the environment).
L
EP,D
Daily personal noise exposure level.
Leq (Equivalent
Level)
The true equivalent sound level measured over the run time. The term Leq is
functionally the same as Lavg except that it is only used when the Exchange Rate
is set to 3 dB and the threshold is set to none.
Logging (Also called Data Logging.) Certain measurements, such as average level (Lavg)
and maximum level (max), can be recorded by the dosimeter at regular intervals.
For example: A dosimeter is set to log Lavg and max at one minute logging
intervals. If the dosimeter runs for one hour, then it would log 60 Lavg results and
60 max levels. You would be able to see the average and maximum levels for
each minute of the one hour run time.
Maximum Level
(L
MAX
)
The highest sampled sound level during the instrument’s run time allowing for the
unit’s Response Time setting (Fast or Slow).
Measurement
Range
The decibel range within which the unit’s measurements are valid.
Minimum Level
(Lmin)
The lowest sampled sound level during the instrument’s run time allowing for the
unit’s Response Time setting (Fast or Slow).
Noise Floor
In a “Perfectly Quiet” room, the Noise Floor is the lowest reading that can be
reached. To minimize additive noise errors, measurements should always be at
least 5 dB above the Noise Floor to be valid. The Noise Floor can cause
inaccurate measurements at low measurement levels.
Peak Level Peak is the highest instantaneous sound level that the microphone detects. Unlike
the Max Level, the peak is detected independently
of the unit’s Response Time
setting (Fast or Slow). Example: The peak circuitry is very sensitive. Test this by
simply blowing across the microphone. You will notice that the peak reading may
be 120 dB or greater. When taking a long-term noise sample (such as a typical
8-hour workday sample for OSHA compliance), the peak level is often very high.
Because brushing the microphone over a shirt collar or accidentally bumping it can
cause such a high reading, you must be careful of placing too much emphasis on
the reading.
PEL (Permissible
Exposure Level)
The A -weighted sound level at which exposure for a Criterion Time, typically eight
hours, accumulates a 100% noise dose.
Projected Time The variable amount of time used to make a projected dose calculation from an
actual dose measurement.