(c) Sensory nerve response. A feeling of warmth will be experienced
when the heating effect occurs on the skin. This phenomenon is most commonly
associated with the frequency range 8,000 MHz to 26,000 MHz.
c. Recent information on research done by the Soviet Union and some Warsaw
Pact countries has indicated a need for further research in the bioeffects of microwave
a. The necessity for exposure controls has been long recognized by the military.
The military has had exposure standards in effect for a number of years.
b. With the enactment of Public Law 90-602, Radiation Control for Health and
Safety Act of 1968, effective 6 October 1971, a performance standard was imposed on
all microwave ovens used in homes, restaurants, food vending, etc.
c. It is important to recognize the difference between an exposure standard and
a performance standard. The performance standard is placed on the equipment,
restricting the hazard that can be experienced from a piece of equipment. The burden,
therefore, is on the manufacturer. The exposure standard, on the other hand, limits the
amount of exposure to a particular hazard an individual should experience, thereby
placing the responsibility on the individual or operator, but not the manufacturer.
3-7. EXPOSURE STANDARDS
a. Exposure standards apply to all microwave sources not covered by Public
Law 90-602. Past research indicated that a power density of 0.2 watts per square
centimeter (W/cm2) was required to produce sufficient damage. The instrumentation for
this research was questionable and it was decided that the power density used in the
research could have been as low as 0.1 W/cm2. The presence of assorted minute
quantities of radiation from incidental sources at various frequencies was taken into
consideration and a safety factor of 10 is settled upon. Thus, the 1958 Tri-Service
Committee established the limit of 0.01 W/cm2 average power density for either
continuous or intermittent exposures at all frequencies. However, this limit does not
consider the following factors:
(1) Time of exposure.
(2) Frequency of radiation.
(5) Sensitivity of organ.