Human Exposure Requirements for R&TTE and FCC Approval

Transcription

1 Human Exposure Requirements for R&TTE and FCC Approval Derek Y. W. LEUNG Founding and Committee Member of EMC Chapter- IEEE-HK Requirements of Non-Specific Short Range Device (SRD) for CE Marking Radio - Generic Standards EN , EN MHz to 1000 MHz, <500mW EN , EN khz to 25 MHz EN , EN GHz to 40 GHz Electromagnetic Compatibility (EMC) EN & EN Electrical safety EN60950: Safety of information technology equipment Human Exposure to EM Fields EN Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.2 Standards of Human Exposure Requirements in R&TTE Directive Requirement of EN50371 EN 50360:2002 :Product standard to demonstrate the compliance of mobile phones with the basic restrictions related to human exposure to electromagnetic fields (300 MHz - 3 GHz) EN 50364:2001: Limitation of human exposure to electromagnetic fields from devices operating in the frequency range 0 Hz to 10 GHz, used in Electronic Article Surveillance (EAS), Radio Frequency Identification (RFID) and similar applications EN 50371:2002: Generic standard to demonstrate the compliance of low power electronic and electrical apparatus with the basic restrictions related to human exposure to electromagnetic fields (10 MHz GHz) - General public EN 50385:2002: Product standard to demonstrate the compliance of radio base stations and fixed terminal stations for wireless telecommunication systems with the basic restrictions or the reference levels related to human exposure to radio frequency electromagnetic fields (110 MHz - 40 GHz) - General public Limit: If the average power emitted by apparatus operating in the frequency range 10MHz -300GHz is less than or equal to 20mW and the transmitting peak power is less than 20W then the apparatus is deemed to comply the basic restrictions without testing. Averaging time is 6 minutes in the frequency range of 10MHz to 10GHz. The average time (in minute) is 68/(f^1.05) in the frequency range of 10GHz to 300GHz, where f is in GHz. For pulses of duration less than 30 microseconds and frequencies between 300MHz and 10GHz, the average power should be less than 20 x prf mw (prf in Hz) Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.3 Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.4

2 Occupational and general public exposure limitations in ICNIRP Guidelines Basic Restrictions in ICNIRP Guidelines The occupationally exposed population consists of adults who are generally exposed under known conditions and are trained to be aware of potential risk and to take appropriate precautions. The general public comprises individuals of all ages and of varying health status, and may include particularly susceptible groups or individuals. Restrictions on the effects of exposure are based on established health effects and are termed basic restrictions. Depending on frequency, the physical quantities used to specify the basic restrictions on exposure to EMF are current density, SAR, and power density. Protection against adverse health effects requires that these basic restrictions are not exceeded. Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.5 Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.6 Basic Restrictions in ICNIRP Guidelines Reference Levels in ICNIRP Guidelines These levels are provided for practical exposure assessment purposes to determine whether the basic restrictions are likely to be exceeded. Some reference levels are derived from relevant basic restrictions using measurement and/or computational techniques. The derived quantities are electric field strength (E), magnetic field strength (H), magnetic flux density (B) and power density (S). Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.7 Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.8

3 Reference Level for Occupational Exposure in ICNIRP Guidelines Reference Level for General Exposure in ICNIRP Guidelines Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.9 Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.10 FCC RF Safety Publications OET BULLETIN 56: general information & FAQ s OET BULLETIN 65: guide for evaluating compliance with FCC RF exposure limits OET 65 SUPPLEMENTS: A: Radio and TV broadcast stations B: Amateur radio stations C: Mobile & portable devices Text available in : Units & Frequencies used for FCC Human Exposure Guidelines Frequency range: 300 khz to 100 GHz exposure limits depend on frequency Maximum Permissible Exposure (MPE) power density: mw/cm 2 field strength: V/m or A/m Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.11 Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.12

4 FCC Limits for Maximum Permissible Exposure (MPE) FCC RF Safety Guide FCC s guidelines establish separate MPE limits for "general population/uncontrolled exposure" and for "occupational/controlled exposure." The general population/uncontrolled limits set the maximum exposure to which most people may be subjected. People in this group include the general public not associated with the installation and maintenance of the transmitting equipment. Higher exposure limits are permitted under the "occupational/controlled exposure" category, but only for persons who are exposed as a consequence of their employment (e.g., wireless radio engineers, technicians). To qualify for the occupational/controlled exposure category, exposed persons must be made fully aware of the potential for exposure (e.g., through training), and they must be able to exercise control over their exposure. Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.13 (A) Limits for Occupational/Controlled Exposure Frequency Electric Magnetic Power Averaging Range Field Strength Field Strength Density Time (MHz) (V/m) (A/m) (mw/cm 2 ) (minutes) (100)* /f 4.89/f (900/f 2 )* f/ , (B) Limits for General Population/Uncontrolled Exposure Frequency Electric Magnetic Power Averaging Range Field Strength Field Strength Density Time (MHz) (V/m) (A/m) (mw/cm 2 ) (minutes) (100)* /f 2.19/f (180/f 2 )* f/ , f = frequency in MHz * = Plane-wave equivalent power density Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.14 Power Density (mw/cm 2 ) Figure 1. 1, Occupational/Controlled Exposure General Population/Uncontrolled Exposure ,000 30,000 Source: of the FCC rules FCC Limits for Maximum Permissible Exposure (MPE) Plane-wave Equivalent Power Density ,500 Frequency (MHz) 100, ,000 Maximum Permissible Exposure Requirement- (Section 47 CFR ) Three different categories : fixed installation, mobile and portable of transmitters are defined by the FCC in OET Bulletin 65. Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.15 Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.16

5 Fixed Installations Mobile Devices Fixed location means that the device, including its antenna, is physically secured at a permanent location and is not able to be easily moved to another location. Additionally, distance to humans from the antenna is maintained to at least 2 meters. A mobile device is defined as a transmitting device designed to be used in other than fixed locations and to be generally used in such a way that a separation distance of at least 20 centimeters is normally maintained between the transmitter's radiating structures and the body of the user or nearby persons. Transmitters designed to be used by consumers or workers that can be easily re-located, such as a wireless modem operating in a laptop computer, are considered mobile devices if they meet the 20 centimeter separation requirement. The FCC rules for evaluating mobile devices for RF compliance are found in section Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.17 Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.18 Portable Devices A portable device is defined as a transmitting device designed to be used so that the radiating structure(s) of the device is/are within 20 centimeters of the body of the user. Portable device requirements are found in Section of the FCC's Rules. Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.19 Date: 21 Jun 2008 By: Derek Y. W. LEUNG P.20