FCC Proposes Changes in Procedures For Determining Human Exposure to RF
June 30, 2003
In a Notice of Proposed Rule Making, the FCC is proposing changes in the current rules and procedures for evaluating compliance with RF exposure guidelines. However, the commission is not considering any changes to the RF exposure guidelines themselves.
A News Release FCC Proposes Changes in the Commission's Rules and Procedures Regarding Human Exposure to Radiofrequency Electromagnetic Energy said, "The Commission's current rules and procedures were adopted and implemented in 1996 and 1997. Since that time, it has become apparent that some aspects of these rules and procedures may need to be revised or modified, based on our experience and on the evolution of services and equipment, and to clarify the responsibilities of Commission licensees and grantees, to better ensure compliance with the Commission's exposure limits in the most practical, reasonable and efficient manner."
Some of the proposals in the NPRM include new rules for routine evaluation of certain unlicensed devices authorized under Section 15.247 of the FCC rules. This section covers frequency hopping and digital spread spectrum devices. Procedures for evaluating RF exposure from modular transmitters used in devices such as laptop computers and for multiple transmitters in a given RF device would also be codified. Devices with a maximum peak output power greater than 100 milliwatts designed for use within 20 cm of the body would require routine evaluation of Specific Absorption Rate (SAR) of RF from the device.
There are specific rules for laptop computers. The FCC is proposing that any transmitter designed to be used in the keyboard section of a laptop be excluded from an RF exposure analysis if it operates at less than 10 mW peak radiated power. Devices more than 20 cm from the user's body (such as screen mounted antennas) would be allowed up to 200 mW without requiring evaluation of RF exposure. The proposed limit for PDAs is 25 mW, unless they are designed to be used in contact with the head or worn against the body, in which case a 2 mW threshold would apply.
Current FCC rules exclude transmitters in some services from routine RF exposure analysis based on power and exclude radiators in other services based on distance. The proposed rules would be more consistent across services and consider both power levels and separation distances. Broadcast services, with the exception of low power FM broadcast stations, would not be affected by these changes.
New rules would require routine evaluation of transmitters that operate within 3 meters of publicly accessible areas, with an exception for certain very low power devices operating with 1.5 W ERP or less mounted in such a way that persons are not normally closer than 20 cm from any part of the radiating structure.
FCC rules Section 1.1310 says occupational/controlled exposure limits apply "in situations in which persons are exposed as a consequence of their employment provided those persons are fully aware of the potential for exposure and can exercise control over their exposure." The NPRM proposes adding a note defining "fully aware" as meaning "that an exposed individual has received written and verbal information concerning the potential for RF exposure and has received training regarding appropriate work practices relating to controlling or mitigating his or her exposure." The NPRM also states that transient individuals simply need to be made aware of their exposure and says this could be achieved "by means of written and/or verbal information, including, for instance, appropriate signage." The words "exercise control" would be specified as meaning "an exposed individual is able to reduce or avoid exposure by administrative or engineering work practices, such as use of personal protective equipment or time averaging of exposure."
The FCC NPRM noted that some licensees assumed that if they met guidelines for public exposure, they did not have to be concerned with occupational exposure. Language would be added to the Section 1.1310 stating, "Licensees and applicants are generally responsible for compliance with both the occupational/controlled exposure limits and the general population/uncontrolled exposure limits in Table 1 as they apply to transmitters under their jurisdiction. Licensees and applicants should be aware that the occupational/controlled exposure limits apply especially in situations were workers may have access to areas in very close proximity to antennas where access to the general public may be restricted."
The NPRM requested comment on use of spatial averaging of RF fields when determining exposure. When is it appropriate?
Refer to the Notice of Proposed Rule Making ET Docket No. 03-137 for more information. The NPRM was released June 26, 2003 and the deadline for comments was set at 90 days after publication in the Federal Register. Reply comments are due 30 days after the comment deadline.