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Note: All IEEE standards are copyrighted and must be purchased directly from IEEE. The links lead only to cover pages.

 

IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz
 
IEEE Recommended Practice for Radio Frequency Safety Programs, 3 kHz to 300 GHz
 
To purchase IEEE standards documents, contact IEEE.

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IEEE Standards

There are two major Institute of Electrical and Electronics Engineers (IEEE) standards relating to RF radiation.

The IEEE standards both have dual designations as American National Standards Institute (ANSI) standards, i.e. ANSI C95.1–2005. The exposure standard has limits for electric fields and magnetic fields that are whole-body and time averaged. It has relaxed limits for an appendage and exposure limits for induced and contact currents.

History

The first ANSI standard that covered RF radiation exposure was issued in 1966. It was four pages in length and recommended that exposure be limited to field levels no higher than 10 mW/cm². Exposure limits were expressed as Radio Frequency Protection Guides (RFPG). Under ANSI rules, committees must meet every five years to reevaluate a standard and either reaffirm or change it as required based on the latest available information. The original standard was updated once in the 1970s, but without substantial change. The first major change came in the 1982 version. ANSI C95.1–1982 became the first Specific Absorption Rate (SAR)-based human exposure standard in the world. All the major standards in the world today are similar and have the characteristic frequency-dependent exposure limits. There are some important differences, but the exposure limits for electric and magnetic fields are all based on the same concepts of body heating and electrostimulation (shocks and burns).

Five years after this major update, the now much-larger group again began the process of reviewing the standard. Amid an atmosphere of dissention and concern over liability issues, the sponsorship of the standard was switched from ANSI to IEEE. IEEE is a larger, stronger organization that is international in scope. Thus the next update of the standard, which incorporated several major changes, was IEEE C95.1–1991. A year later, it was ratified by ANSI. The latest version represents only modest changes and clarifications from that landmark standard.

Exposure Limits

The IEEE standard has exposure limits for electric fields and magnetic fields that are whole-body and time averaged. Limits are expressed in terms of Maximum Permissible Exposure (MPE). MPE limits for the magnetic (H) field are relaxed below 100 MHz since the exposure limits at lower frequencies are based on electrostimulation rather than body heating, and both induced and contact currents are related to the strength of the electric field. There are also limits for induced currents and contact currents.

Electric Field Limits

The IEEE’s MPE limits for the two environments are shown in the tables below. Limits are spatially averaged over the whole body. The are time averaged over 6 minutes. The averaging time for uncontrolled environments is 30 minutes. The averaging times decrease at frequencies above 3 GHz due to concern over eye damage.

MPE Limits for Controlled Environments
Frequency (MHz) Power Density (W/m²)
0.1–1.0 9,000
1.0–30 9,000/f²
30–300 10
300–3,000 f/30
3,000–300,000 100

 

MPE Limits for Uncontrolled Environments
Frequency (MHz) Power Density (W/m²)
0.1–1.34 1,000
1.34–30 1,800/f²
30–400 2.0
400–2,000 f/200
2,000–100,000 10
100,000–300,000 Increases from 10 to 100