Introduction to RF Radiation Safety / 10 / 10.6 / 10.6.4

10.6.4 Considering The Nature Of The Work

Risk depends on the complete exposure scenario and work activity, not on a single field strength reading.

The assessment should consider:

• source operating states, duty cycle, beam direction, and simultaneous sources;
• task duration and frequency in relation to the applicable averaging time;
• whole-body or localized exposure and the person's position and posture;
• proximity to the source and the spatial non-uniformity of the field;
• direct exposure, contact-current, spark, shock, burn, and other secondary hazards;
• environmental heat, physical exertion, clothing, and other thermal stressors;
• the exposure category and any pregnancy, medical-device, or metallic-implant arrangements;
• the effectiveness, reliability, and possible failure of existing controls; and
• reasonably foreseeable errors, access, abnormal conditions, and workplace changes.

For example, a maintenance location may be safe when the relevant transmitters are de-energized, isolated, and verified, but unacceptable when a transmitter remains active or another operator's source is overlooked. The assessment must therefore describe the source states and controls on which its conclusion depends.

10.6.5 Likelihood And Consequence

Many organizations use a qualitative risk matrix to prioritize actions after the technical exposure assessment has established the potential exposure and compliance status. The matrix should address the likelihood that the assessed scenario will occur and the consequence if it does.

Likelihood may depend on factors such as:

• accessibility of the source or affected area;
• frequency and duration of the task;
• whether the source is energized during the task;
• effectiveness, reliability, and verification of existing controls; and
• reasonably foreseeable failures, deviations, or human error.

Potential consequence may depend on:

• the magnitude and duration of any exposure above the applicable limits;
• whether exposure is whole-body or localized;
• the potential for contact-current shocks, sparks, or RF burns;
• other thermal stressors or conditions that may impair thermoregulation; and
• the number of people who could be affected and any resulting secondary injury.

Considering likelihood and consequence helps prioritize corrective action, but it does not permit exposure above the applicable limits.