Safety Practices - hdbk10920206

DOE-HDBK-1092-98

10.8.3.3

SAFETY PRACTICES

An analysis of high-voltage circuits should be performed by a qualified person before work begins

unless all exposed energized parts are guarded as required for high-voltage work. The analysis must

include fault conditions where circuit current could rise above the nominal rated value as explained

here and shown graphically in Figure 10-1. Depending on the results of the analysis, any of the

following may apply:

1. If the analysis concludes that the current is above 5 mA or energy is above 10 J, then the work

is considered to be energized work and should be performed in accordance with Section 2,

"General Requirements" and/or Section 7, "Work In Excess of 600 Volts."

2. If the analysis concludes that the current is between 0.5 mA and 5 mA and between 0.25 and

10 J, then the worker may be exposed to a secondary hazard (e.g., startle reaction) that must

be mitigated.

3. If the analysis concludes that the current is below 0.5 mA and below 0.25 J, then the worker

exposure is minimal and no special precautions are required.

High-voltage supplies that use rated connectors and cables where there are no exposed energized

parts are not considered hazards. Connections shall not be made or broken with the power supply

energized unless they are designed and rated for this type of duty (e.g., load-break elbows). Inspect

cables and connectors for damage and do not use if they are damaged. Exposed high-voltage parts

must be guarded to avoid accidental contact.

10.8.4 RADIO-FREQUENCY/ MICROWAVE RADIATION AND FIELDS

The DOE complex conducts R&D programs that involve sources of radio-frequency/microwave

(RFMW) nonionizing electromagnetic radiation. Devices that may produce RFMW radiation

include telecommunications and radar equipment, industrial equipment such as radio-frequency

heaters, and scientific and medical equipment such as magnetic resonance imagers and klystron tubes.

The nationally recognized consensus standard for personnel exposure to radio-frequency radiation is

ANSI/IEEE C95.1(1991), "Electromagnetic Fields, Safety Levels with Respect to Human Exposure

to Radio Frequency."

10.8.4.1

HAZARDS

1. RF amplifiers frequently use high-voltage power sources. See Section 7.0, "Work in Excess

of 600 V", for high voltage requirements.

2. There may be x-ray hazards (when supply voltage exceeds 10 kV).

3. Currents may be induced in conductive objects or metal structures that are not part of the RF

structure.

4. RF currents can cause severe burns.

5. Falls from towers may result from RF burns from antennas.

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