DRAFT Recommended Practice for Measurements and ...

1/29/98 72 C95.3-1991 Revision — 2 nd Draft
10/98 Draft
(b) It is generally important to realize that potential EM interference to electronic
devices or systems often occurs at levels far below those that cause bodily
harm. This interference may be only an annoyance, for example the effects of
low-elevation radar operation on TV or consumer electronic devices in homes,
or it may be more serious, such as causing the possible reprogramming or
‘’upsets’’ of microprocessor-controlled medical devices, e.g., pacemakers, or
causing errors in digital computers controlling industrial processes. In any
case, such interference is undesirable, and care should be exercised when
operating systems, particularly in abnormal modes of operation that may be
useful for survey purposes. A clear assessment of the impact of potential
interference problems should always be made before beginning a survey. It is
also understood that surveys are to be made with responsible adherence to
the rules of the Federal Communications Commission and other bodies that
regulate against RF interference.
(5) Burns. (Associated with high-power fields.) One should take care to prevent RF
burns resulting from handling conducting objects exposed to these fields or RF
cables with exposed connectors [B105]. In addition, one should follow ordinary
precautions in the operation of RF heating systems and plastic sealers during
surveys, e.g., avoid handling test loads, sealing bars and superheated liquids.
(6) Abnormal Modes of Operation. One should be aware that electronic systems
have the potential for abnormal modes of operation in which spurious frequencies
and unintended leakage radiation are generated at significant power levels. The
operation of a system should not be attempted by the surveyor without qualified
personnel present to assess the normality of operation, in order to avoid such
situations.
(7) Fall Hazards. Personnel performing RF field surveys must always be aware of
the potential for falling from roof-top or tower antenna sites, elevated antenna
pedestals, etc. The use of safety lines and climbing harnesses is recommended.
5.2.2 Precautions During the Survey Process.
Serious precautions are clearly required when surveying a radiating system, such as a
high-power radar. Such precautions include the following:
(1) Based on known parameters of the system, the survey process should be
planned so as to limit exposure of all personnel to levels below the MPE specified
in the latest version of IEEE C95.1-1991 [1], or other applicable exposure guides
or standards. This limitation relates not only to power density, but also exposure
duration. If survey personnel are exposed to field strengths in excess of those
specified in the guides for continuous exposure, they should be accompanied by
other personnel who can ensure that the exposure duration does not exceed the
time recommended in the MPE for exposure to higher level fields (see 3.2.2). In
such situations, it may be desirable to conduct the survey with radiation-emitting
equipment operating at a reduced power level and use power scaling to compute
the corresponding field levels that would exist during full-power operation.
(2) The operation of movable or scanning antennas should be done with full
allowance for safety precautions. These precautions range from avoiding injury
from bodily collision with rotating or moving structures, to avoiding start-up
Copyright © 1998 IEEE. All rights reserved. This is an unapproved IEEE Standards Draft,
subject to change.