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1. UNDERSTANDING SAR AND EMF EXPOSURE REQUIREMENTS FOR EQUIPMENT CERTIFICATIONSession 2: Requirements for ComplianceOctober 20, 2011
2. Presentation Outline – Session 2 SAR Assessment Standards
SAR Assessment Procedures
Phantom Head
Test Positions
Liquids Used
The Robotic System
Measurement Method
Measurement Reports
SAR Reporting
Q&A’s
3. SAR ASSESSMENT STANDARDS
4. IEEE ICES TC95/SC1
9. Worldwide Harmonization of RF standards One RF safety standard
IEEE C95.1/ICNIRP guidelines
Harmonized on major issues and limits
One mobile phone SAR measurement standard
IEC 62209-1&2/IEEE 1528
Totally harmonized SAR assessment methods
10. SAR ASSESSMENT PROCEDURES
11. Assessment Basics A SAR measurement system comprises:
a phantom human head and a body model.
specially developed liquids,
a robot fitted with a measurement probe,
and a mobile phone powered up to its maximum certified power level.
12. The Phantom Head The phantom head is based upon the dimensions of a large adult male head.
Studies show that that a larger head produces a higher SAR.
Phantom has compressed thin ears to simulate users with small ears.
In addition – right and left model heads are used to ensure that the different exposure areas caused by the asymmetric location of the antenna are being measured.
13. The Phantom Head
14. Handset Reference Lines
15. Touch Position
16. Tilt Position
17. The Flat Phantom For body-worn devices and products used in close proximity to the body IEC 62209-2 specifies a flat phantom to be used.
18. The Liquid The liquid correlates with the dielectric properties of human head tissue.
Calculated taking into account the properties of human brain tissue and outer tissue layers of the head (e.g., skin and skull)
Studies suggest it provides conservative overestimate of the values.
Different ‘recipes’ are used for tests on different frequencies.
19. Liquid Stimulant Materials Sucrose (>98% pure)
Sodium Chloride (>99% pure)
De-ionized water
Hydroxyethyl Cellulose (HEC)
Bactericide
Diethylene Glycol Butyl Ether (DGBE)
Triton X-100
Emulsufiers
Mineral Oil
20. Sample “Recipe”
21. The Robotic System Consists of a mechanical arm and a special probe
Begins by establishing a reference point in the phantom and then scanning throughout phantom while phone is operating at its maximum certified power level.
22. The Robotic System
23. Measurement Process
24. Measurement Process The scan determines the electric field strength within the head – resulting in a three dimension map indicating the maximum SAR value recorded during the test.
25. System Validation As SAR measurement is a complicated procedure system validation is very important:
Performance Checking (daily)
System Validation (annual)
Calibration (annual)
Inter-laboratory Comparison
26. Measurement Test Reports General introduction
Identification of the test laboratory and device including hardware and software revision numbers, serial number, e.g., IMEI
Measurement system
Measurement system description
Calibration data for relevant components
Description of interpolation/extrapolation scheme used
Liquids used and characteristics and results of system check
Device and test details
Description of the positions and orientations tested
Available and tested antenna(s) and accessories incl. batteries
Tested operating modes, power levels and frequency bands
Report summary
Tabulated SAR values over the testing positions, bands, modes and configurations
Reference to exposure limits and a statement of compliance
27. Example: Two-way Radio Compliance Tested using occupational limit due to professional use
50-50 Tx-Rx Duty Cycle (divide by 2)
Max Power, Intended Use
Approved Accessories (antennas, batteries, audio & body-worn)Note: Some radios evaluated to general public limits depending on product and the intended market.
28. SAR REPORTING
29. Background SAR reporting commenced in 2001.
Little real interest from consumers based on web-site stats, enquiries to help-lines or evident at retail level.
However recent political developments in a number of countries and the introduction of IEC 62209-2 meant that it was time to review and updated reporting format and key elements.
30. Phase II Elements (A) The inclusion of one additional information/guidance note in the ‘health and safety section/important product information section’ of the user manual.
31. This information will be included in the first few pages of the manual along with other product safety information.
It includes both SAR and body-worn compliance information and includes a SAR-Tick pictogram to visually reinforce the message.
The overall format addresses a number of issues:
Greater visibility of SAR information in the manual
Consistency between manufacturers in its placement
Affirmative statement and information on compliance
Provides a link to full SAR text elsewhere in manual and to SAR-Tick.com website for consumers wanting more information
SAR-Tick artwork is available freely for MMF members. Non-members will need to approach the MMF for licensing terms.
Phase II Elements
32. (B) The development of SAR-Tick website to provide comprehensive information source on SAR issues.
WWW.SAR-TICK.COM will be a comprehensive resource on all aspects of SAR and will be available in many languages.
Consumer groups will also be approached to help educate consumers on SAR issues and to promote awareness of SAR-Tick.com website.
Phase II Elements
34. (C) Modification of the existing SAR information text. Phase II Elements
35. The inclusion of the new SAR table contains important elements:
Both head and Body-worn SAR values are included.
Values are displayed more prominently in the text.
The measurement conditions under which the max. SAR was recorded are specifically mentioned.
This approach addresses key issues raised in the past (prominence) ensures compliance with latest IEC commitments, and ensures that misleading comparisons of SAR by ‘ranking’ phones SAR cannot be undertaken.
The text retains information for consumers on practical measures to reduce exposure if they are concerned.
Phase II Elements
36. Conclusion Scientifically, one RF safety standard now exists
Along with harmonized mobile phone SAR measurement standard
IEC 62209 Parts 1 & 2 should be used to show compliance with ICNIRP limits
SAR limits have been designed to ensure protection for all members of the community
SAR testing methodology is complex but conservative
Risk communication is also an important element for public confidence.