ETS-Lindgren HI-3603 VLF Survey Meter - Manual (Page 37)

HI-3603 VDT/VLF Survey Meter
© ETS-Lindgren, August, 2005
Revision E, Part #H-600042 37
are generally healthier, and possible exposure to potentially
hazardous physical agents is usually under much better control.
For example, employers can inform workers of situations which
should be avoided; this is not the case for the general population
as a whole. Regardless of these considerations, it is informative
to examine some of the recommended exposure guides that
apply to different organizations and/or countries.
The following table summarizes the electromagnetic field
exposure standards found in the literature that either directly
apply to the frequency range appropriate to VDT emissions or
pertain to a frequency range close to that of interest. As can be
seen, the primary difficulty in applying many RF exposure
standards to VDT emission levels is that the applicable
frequency range of the standards does not extend down low
enough. From the literature searched, only one reference was
found that offered a quantitative emission limit as a guideline
specific to VDT's (Telecom, 1984). This Occupational Health
Policy Guideline for screen based equipment was developed by
Telecom Australia for internal use until such time as there is a
national standard for VDT's in Australia. The guide specifies that
the levels of radiation emitted from cathode-ray VDT's in the
frequency range of 50 Hz to 0.3 MHz shall be as low as possible,
and should not, at any time, exceed an electric field strength of
50 V/m, measured 30 cm from the terminal.
The reader of this manual is cautioned that a number of RF
exposure standards are presently under development or revision
and that Table 1 should be used more as an orientation to
existing standards.