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A free electronic newsletter covering news and other topics for those interested in RF safety issues.
LIVE, Web-Based RF Safety Training
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Overview The FCC adopted new regulations in 1997. They became fully effective on September 1, 2000. It is a two-tier standard with frequency-dependent exposure limits, referred to as Maximum Permissible Exposure (MPE) limits, which are time averaged. Time averaging—6 minutes for Occupation/Controlled exposure below 15 GHz—is specifically called out. Unlike other standards and regulations, the FCC does not allow time averaging for General Population/Uncontrolled exposure. The exception is if the environment is “controlled”, which means time averaging rarely applies for general population areas. Although spatial averaging is not specified, the FCC is on record as fully accepting and supporting spatial averaging. There is, however, no specific spatial-averaging method specified. There are currently no limits for induced currents or contact currents. The FCC’s position on the two tiers has steadily moved towards that of OSHA’s. In essence, an organization must be operating under an RF Safety Program in order to operate at levels up to the less restrictive Occupational/Controlled MPE limits. The official regulations document is a Report and Order. In addition, the FCC's Office of Engineering and Technology (OET) has issued Bulletin No. -65 Evaluating Compliance With FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields. This is a guidance document—not the regulations! However, OET Bulletin No. 65 has a great deal of practical information while the regulations can be difficult to follow. See Radio Frequency Safety in the OET section of the FCC web site. www.fcc.gov/oet/rfsafety/ There are three supplements to Bulletin No. 65:
History The FCC adopted the first frequency-dependant standard, ANSI C95.1-1982, in 1996. In April 1993 the FCC issued a Notice of Proposed Rule Making (Docket 93-62), indicating that it planned on adopting the new IEEE standard. After three filing extensions, more than 3,000 pages of comments, and a long delay caused by the EPA's planned development of a standard (which was later abandoned), the FCC finally issued its new regulations on August 5, 1996. The new regulations are actually a hybrid, drawing primarily on the 1986 NCRP Report 86 (paragraph “D”) for its field limits, but borrowing certain aspects of the 1991 IEEE standard (paragraph “C”). The FCC made much of the fact that this is the first standard in the United States that is publicly supported by all of the major Federal health agencies—EPA, OSHA, and NIOSH. The implementation date was delayed from January 1, 1997 to September 1, 1997 and was delayed again to October 15, 1997. Requirements were phased in for existing sites through September 1, 2000. The new regulations are now fully in affect. The FCC abandoned its long anticipated plans to adopt the popular IEEE C95.1-1991 standard due to severe criticism from the EPA. Although the EPA abandoned their plans to issue a new set of recommendations of their own; it made its position very clear. The area of the new IEEE standard that the EPA objected to the most was the relaxation of the limits from ANSI C95.1-1982's 5 mW/cm2 at frequencies above 1.5 GHz to the IEEE’s 10 mW/cm2 at frequencies above 3 GHz. The FCC did not want to appear to be opposing the federal government's leading health agency, even though most of the country had adopted the IEEE standard or one of its clones. The EPA does support the addition of limits for induced and contact currents, which the FCC intends to add in the future. Exposure Limits
Table 1 Maximum Permissible Exposure (MPE) Limits Time Averaged, Whole Body Occupational/Controlled Exposure
Table 2 Maximum Permissible Exposure (MPE) Limits Whole Body General Population/Uncontrolled Exposure
Occupational/Controlled Exposure The FCC has tried to define what constitutes an "Occupational/Controlled" exposure with limited success. In addition to the need for an RF Safety Program to be in place, two terms used in the FCC’s regulations help define the requirements to qualify for the less restrictive MPE limits for Occupational/Controlled Environments. The phrase “fully aware” refers to workers that: · Have received both written and verbal information regarding RF radiation. · Have received training that includes how to control or mitigate RF radiation exposure. The phrase “exercise control” refers to workers that: · Understand how to use administrative controls and engineering controls to reduce their exposure level. These controls include time averaging, RF personal monitors, and RF protective clothing. |
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