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FCC Radiofrequency Exposure Rules—47 CFR §§ 1.1307, 1.1310, 2.1091, and 2.1093

Preview: Learn more about the FCC RF Exposure Rules governing evaluation, limits, mitigation, and mobile and portable devices in the United States.

The United States Federal Communications Commission (FCC) regulates human exposure to radiofrequency (RF) energy through legally enforceable rules in Title 47 of the Code of Federal Regulations. Four sections are central to the framework: § 1.1307 establishes RF environmental-evaluation, exemption, mitigation, and shared-site responsibilities; § 1.1310 states the exposure limits; § 2.1091 addresses mobile devices; and § 2.1093 addresses portable devices.

These rules must be distinguished from FCC OET Bulletin 65 and Knowledge Database publications. The regulations are binding requirements. OET Bulletin 65 is explanatory engineering guidance, and FCC KDB publications provide current staff procedures for many equipment-authorization assessments. Guidance helps a party demonstrate compliance but does not replace the current text of the rules, Commission orders, or applicable service and authorization requirements.

Section 1.1307—Evaluation and Mitigation

Section 1.1307 requires an applicant or authorization holder to determine whether an RF source qualifies for an exemption from routine evaluation, to perform an evaluation confirming compliance with § 1.1310, or to prepare an Environmental Assessment where the source would cause exposure above the limits. An exemption removes the obligation to perform a routine environmental evaluation; it is not permission to exceed the exposure limits.

The section provides screening criteria for individual and multiple sources and requires cumulative contributions to be considered where appropriate. If simple exemption criteria are not met, compliance may still be demonstrated by measurement, computation, source-specific procedures, or mitigation. The method and assumptions must represent the maximum time-averaged power, antenna or radiating structure, separation distance, simultaneous operation, and accessible exposure conditions.

For fixed sources, § 1.1307 organizes locations into exposure categories and prescribes mitigation where the general-population or occupational limits can be exceeded. Measures include RF safety plans, signs, positive access control, training, supervision, time management, power reduction, and lockout/tagout where necessary. The required controls become more stringent as potential exposure increases.

At multi-transmitter sites, responsibility can be shared among licensees whose sources make a material contribution to an accessible area that exceeds the applicable limit. Licensees must exchange technical information needed for joint compliance, while site owners and managers are expected to facilitate reasonable compliance measures. A defensible site assessment therefore considers the total RF environment rather than only one operator's equipment.

Section 1.1310—Exposure Limits

Section 1.1310 contains the FCC limits for occupational or controlled exposure and for general-population or uncontrolled exposure. The limits vary with frequency and include maximum permissible exposure quantities for external fields as well as specific absorption rate and other provisions relevant to localized exposure and higher-frequency operation.

The occupational or controlled category applies when exposure is related to employment, the person has been made fully aware of the potential exposure, and the person can exercise control over it. The general-population or uncontrolled category applies to the public and to situations in which exposed people may not know about the source or cannot control the exposure. Employment alone is not sufficient to justify use of the occupational limits.

Spatial and temporal averaging are integral to the limits. Source duty cycle, scanning, power control, traffic variation, and intermittent operation may be relevant, but averaging cannot be used casually to excuse uncontrolled entry into a high-field area. The exposure scenario, averaging period, access arrangements, and mitigation must satisfy the specific rule provisions.

Sections 2.1091 and 2.1093—Mobile and Portable Devices

Section 2.1091 applies to mobile devices, which are generally used with at least 20 centimeters separation between the radiating structure and the body of the user or nearby persons. Examples include certain vehicle-mounted transmitters and fixed wireless equipment. Evaluation is normally based on maximum permissible exposure unless the applicable authorization procedure requires a more refined assessment.

Section 2.1093 applies to portable devices used with the radiating structure within 20 centimeters of the body. Phones, body-worn transmitters, tablets, and similar equipment may fall within this category. Compliance commonly requires specific absorption rate below 6 GHz or power-density or absorbed-power-density procedures at higher frequencies, subject to current FCC rules and KDB guidance.

The 20-centimeter distinction is a regulatory classification rule, not a universal boundary between safe and unsafe exposure and not a definition of the electromagnetic near field. The actual assessment method depends on the device design, frequency, antenna position, intended use, and applicable equipment-authorization procedure.

Exemptions and Routine Evaluation

The FCC rules provide power- and distance-based criteria for determining whether a source is exempt from routine RF exposure evaluation. Separate provisions address multiple sources. A source that does not qualify for an exemption is not necessarily noncompliant; it requires an evaluation showing that the applicable exposure limits are met.

Current exemption formulas and thresholds should be taken directly from the current eCFR and applicable FCC procedures. They have changed over time, and older summaries may omit source-based time averaging, multiple-source treatment, or revised higher-frequency requirements. Project records should identify the rule edition and guidance used for the decision.

OET Bulletin 65 and Current FCC Guidance

FCC OET Bulletin 65 remains a useful introduction to facility calculations, measurements, multiple-source assessment, and the distinction between controlled and uncontrolled exposure. Its principal edition dates from 1997, however, and it predates later rule revisions and many modern technologies. It should be used with the current rules, Commission orders, service-specific material, and FCC KDB publications.

This distinction is especially important for equipment authorization. OET Bulletin 65 Supplement C has been discontinued, and contemporary mobile and portable-device evaluations rely on current FCC KDB procedures. Active arrays, beamforming, millimeter-wave devices, simultaneous transmitters, and unusual near-field configurations can require newer methods.

Practical Application

For a fixed facility, an FCC assessment identifies relevant RF sources, determines exemptions or performs evaluation, compares cumulative exposure with § 1.1310, and maps areas requiring controls under § 1.1307. The resulting RF safety plan should allocate responsibilities, identify category boundaries, control access, specify signs and work procedures, and require reassessment after material modifications.

For a wireless product, the assessment must classify the device and intended use correctly, then apply current authorization and test procedures. Antenna separation, simultaneous transmission, accessories, power control, and software-enforced limits may all be relevant. Compliance documentation must support marketed configurations.

Together, the four sections form a regulatory chain: § 1.1310 defines the exposure limits; § 1.1307 determines when evaluation and mitigation are required; and §§ 2.1091 and 2.1093 apply the framework to mobile and portable devices. Practitioners should verify current rules and guidance rather than rely solely on an older summary or prior authorization.