| Basic
Construction
Dosemeters
are small, lightweight
personal monitoring
instruments which are
used to measure Leq
exposure levels,
ie., noise dose.
They are
battery operated and
in simple terms
comprise a microphone
attached by a flexible
cable to a special
form of integrating
sound level meter.
The dosemeter
electronics are
enclosed in a small
case which is usually
worn in the top
pocket.
Alternatively,
this may be worn on a
waist belt.
Perhaps
the most obvious way
in which dosemeters
from different
manufacturers vary is
in the position of the
control switches and
the read-only display.
Some display
the measurement
directly as an Leq
level, whilst others
display the noise dose
as a percentage which
needs to be corrected
to an Leq
level using a nomogram
(chart) supplied with
the instrument.
This is not a
particularly difficult
task and would not be
a major reason for
selecting one type of
dosemeter in
preference to another.
More
sophisticated (and
expensive) dosemeters
are now available
which will essentially
act as personal sound
level meters,
electronically storing
sound data from the
sampling period.
The date can be
downloaded later,
enabling a time
history (amongst other
things) to be plotted
of exposure, including
noise levels from
discrete peaks.
Standards
The
current British
Standard covering
noise dosemeters is BS
6402:1994 Electro
acoustics
specification for
personal sound
exposure meters.
The standard
describes only one
instrument type which
is equivalent to type
2 as defined in BS EN
60651.
» Basic
Construction
» Principles
of Operation
» Dynamic
Range
» Calibration
» Use
of Dosemeter in the
Field
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