Why use a noise
dosimeter?
The 1954 noise dosimeter is designed to save you time and money
in the measurement of noise for computation of personal noise
dose. In industrial environments where noise levels vary constantly,
noise-dose measurements are the easiest method of determining
both the risk of hearing damage and compliance with the law. Computing
noise-dose in virtually every industrial environment would necessitate
tedious day-long measurements with a sound-level meter and timing
with a stop watch. This is necessary because noise dose is computed
by the formula:
where D is noise dose, C is the actual duration (in hours) at a
given steady noise level and T is the noise exposure limit (in hours)
from the table below:
| Sound
Level [dBA] |
90 |
95 |
100 |
105 |
110 |
115 |
Time
permitted [hours] |
8 |
4 |
2 |
1 |
0.5 |
0.25 |
Computing noise with a sound-level meter is generally impractical
and expensive. A noise dosimeter performs the measuring, timing,
and computing automatically. You need only read the computer answer
at the end of the measurement period.
Unsurpassed for noise-dose measurements
The primary function of the 1954 is automatic monitoring of sound
levels and computing personal noise dose based on current OSHA
noise limits and other established standards. Should the limits
change you can readjust the 1954 yourself, quickly and easily.
A screwdriver is all you will need to adjust the exchange rate,
criterion level, threshold level and maximum allowable level.
There is no expense or lost measurement time since the 1954 need
not be returned to the factory or a service center for adjustment.
Noise dose measurements are simple and automatic
At the start of the workday or other monitoring period, your noise-program
supervisor turns on the small wearable monitor by means of a concealed
on-off switch. operating controls are concealed to discourage
tampering. The monitor is then calibrated (about 10 seconds),
clipped in a pocket or waistband, and the tiny microphone is positioned
at the ear, on a collar, or wherever you desire. Noise levels
to which the wearer is exposed are then monitored continually
throughout the workday, and noise dose is computer automatically
without any effort or operating requirements on the part of the
employee or noise program supervisor.
Reading the noise dose is quick and easy
At the end of the measurement period the monitor is plugged into
the 1954 Indicator. You simply push a button to retrieve the computed
noise dose which is then displayed on a 4-digit electronic display.
The number is the actual percentage of the OSHA criterion limit.
A display of 085.0, for example, means the total noise dose is
85% of the OSHA maximum, a safe level. A reading of 145.0 indicates
that the noise dose exceeds OSHA limits by 45% and that some corrective
action is required
Since the OSHA maximum allowable noise level is 115 dBA, the 1954
is designed to indicate if 115 dBA was exceeded during the measurement.
This is shown by a lamp on the indicator that lights during readout
of the noise dose
Calibration takes less than 10 seconds
The 1954 Indicator features a built-in calibrator that lets you
check the complete instrument from the microphone to the display
at the push of a button. Unlike other dosimeters, the 1954 can
be continuously adjusted during the calibration period, with the
screwdriver provided. An opening in the monitor case provides
access to the calibration adjustment so that the case need not
be taken apart. The procedure is as simple as calibrating a sound-level
meter.
A complete calibration check takes less than 10 seconds and is
recommended at the beginning and end of each measurement period.
A separate calibrator is not required, as with other systems.
Work area noise-exposure measurements
You can use the 1954 to measure the noise dose of specific work
areas. These measurements are also completely automatic. The procedure
is simple. Just switch on the monitor, plug it into the indicator,
position the microphone on the microphone extension, and place
the 1954 on a table or set it up on a tripod in the area to be
measured. At any time during the measurement period, you can check
the computed noise-dose answer by pushing the "display"
button. This does not erase the memory and allows you to continue
the measurement for the full period.
Equivalent sound-level measurements
Noise survey measurements, usually made with a sound-level meter,
are another function of the 1954. Again you plug the monitor into
the indicator and position the microphone on the removable extension.
Sound-level measurements are made by pressing the "reset"
button. In a few seconds, you'll get a reading on the digital
display that you can convert to dBA by simply reading the conversion
chart printed on the monitor face.
Users concerned with community-noise measurements can select a
3-dB exchange rate monitor which allows "Leq"
measurements prescribed in many community noise ordinances.
User adjustable
Obsolescence due to changes in OSHA or other noise criteria is
not a factor when you buy the GenRad 1954. provision is made for
you, the user, to readjust the 1954 to meet most changes when
they occur. And all you need is a screwdriver. There is no service
charge to be concerned with, and no time lost in returning your
instrument to the factory or a service center.
The versatility of the 1954 precludes the need to buy a separate
sound-level meter and/or area noise monitor for many users. And
of community-noise measurements become a factor in the future,
and additional monitor is all you need for Leq measurements. |
;)
