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Suggested Citation:"8 All Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2017. Airport Passenger Screening Using Millimeter Wave Machines: Compliance with Guidelines. Washington, DC: The National Academies Press. doi: 10.17226/24936.
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8

All Conclusions and Recommendations

CHAPTER 3. RADIATION PROTECTION STANDARDS

Finding 3.1: Few studies have looked at millimeter waves at frequencies and/or intensities used for AIT.

Finding 3.2: In the United States, the main federal agency responsible for RF health and safety is the FCC, with the FDA responsible for medical devices and radiation-emitting products.

Finding 3.3: The RF exposure limits published by various organizations are similar to one another in terms of power density (W/m2) across the RF spectrum, and are based on the principle of protecting individuals against potentially adverse effects resulting from tissue heating. Limits on peak pulsed RF fields vary substantially.

Finding 3.4: Limits set on average power density fields are set as 10 W/m2. However averaging times used might differ.

Recommendation 3.1: The Transportation Security Administration should adopt source-based time averaging.

Suggested Citation:"8 All Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2017. Airport Passenger Screening Using Millimeter Wave Machines: Compliance with Guidelines. Washington, DC: The National Academies Press. doi: 10.17226/24936.
×

CHAPTER 4. REVIEW OF PREVIOUS STUDIES OF MILLIMETER WAVE AIT

Finding 4.1: The committee finds previous reports having recorded values between 3,000 and 250,000 times lower than the recommended exposure limit of 10 W/m2 from active AIT millimeter wave portals.

Finding 4.2: Previous reports applied various assumptions on how to measure and average the pulsed signal from an active AIT millimeter wave portal, which might explain some of the differences in their findings.

Recommendation 4.1: The Transportation Security Administration should ensure that any future analysis of active portals are evaluated in a consistent way and that the measurement methodology and the results are made available to the public in a clear and understandable way in relation to the applicable standards.

CHAPTER 5. PERSONAL IMPLANTS AND MEDICAL DEVICES

Finding 5.1: There seems to be no available documented evidence of any deviation or effect from normal operation of preemptive medical devices when being scanned with a millimeter wave AIT. However, there seem to be many cautionary warnings of potential deviations.

Finding 5.2: The frequency range for current millimeter wave portals is such that the power is mostly deposited in the outer surface or skin of the body; therefore, devices that are not deeply embedded, or only partially, embedded might be of greater concern.

Finding 5.3: The TSA gives travelers with implanted electronic devices, whether life sustaining or therapeutic, a choice between hand screening and millimeter wave AIT. Travelers may weigh the advice of their physicians and the device manufacturers against the absence of evidence of any deviation or effect from normal operation of preemptive medical devices when being scanned with a millimeter wave AIT.

Finding 5.4: Travelers with implanted medical electronic devices may wish to carry with them a proper medical identification card or a TSA notification card describing their device and to keep up to date with the latest physician and manufacturer recommendations as well as guidelines from the TSA.

Suggested Citation:"8 All Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2017. Airport Passenger Screening Using Millimeter Wave Machines: Compliance with Guidelines. Washington, DC: The National Academies Press. doi: 10.17226/24936.
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CHAPTER 6. COMMITTEE-LED MEASUREMENTS

Finding 6.1: The committee-led measurements at airports indicate that even an “out of position” person will receive an average pulsed power density during a scan that is 270,000 times below the applicable standard exposure limit of 10 W/m2 and most likely will receive even less standing correctly in the center of the portal.

Finding 6.2: The committee-led measurements at airports indicate that even at the entry position of the portal, the power density is several million times below the acceptable limit, even for a continuous signal.

Finding 6.3: The committee finds that during normal operation of the ProVision ATD and ProVision 2 systems there is no risk to a person being screened to receive the applicable standard exposure limit of 10 W/m2; instead, the exposure is hundreds of thousands times less.

CHAPTER 7. SYSTEM DESIGN AND EXPOSURE RISK

Finding 7.1: The installation procedure leaves the ProVision system in a normal operating condition in which both the RF and mechanical systems are operating as designed.

Finding 7.2: ProVision self-diagnostics will detect failures that occur during operation of a sweep, requiring the operator to either allow the system to self re-calibrate or take the system offline.

Finding 7.3: Maintenance of the ProVision systems returns the system to its nominal operating condition.

Finding 7.4: Practically all potential malfunctions of the ProVision system are caught during the cycle of scanning just one individual.

Finding 7.5: Maximum power output of the ProVision transceiver is 0.032 W, and signal losses from the transceiver to the antennae are significant (in the range of 25 dB to 40 dB) and will not be decreased by system use or damage to the passive elements (cables and switches).

Finding 7.6: It appears that no FMEA following established procedures was conducted while the active ProVision millimeter wave AIT portals were designed and manufactured.

Suggested Citation:"8 All Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2017. Airport Passenger Screening Using Millimeter Wave Machines: Compliance with Guidelines. Washington, DC: The National Academies Press. doi: 10.17226/24936.
×

Recommendation 7.1: The Transportation Security Administration should require Failure Mode and Effects Analysis following established procedures to be done on any complex systems it plans to put into operation.

Finding 7.7: The mechanical subsystem of the ProVision does not affect the dose delivered during failure scenarios involving the scanner arms stopping or the antenna switch failing.

Finding 7.8: The ProVision signal path can at best remain stable; any changes in the path can only cause further signal power loss, there is no way to alter the design inadvertently to produce an unintentional increase in the signal power.

Finding 7.9: The ProVision signal power cannot be higher than during normal operation due to the system transceiver operating at full saturation.

Finding 7.10: It is not possible for the scanned subject in the ProVision to be exposed to a power level exceeding the recommended maximum exposure limit of 10 W/m2.

Suggested Citation:"8 All Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2017. Airport Passenger Screening Using Millimeter Wave Machines: Compliance with Guidelines. Washington, DC: The National Academies Press. doi: 10.17226/24936.
×
Page 133
Suggested Citation:"8 All Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2017. Airport Passenger Screening Using Millimeter Wave Machines: Compliance with Guidelines. Washington, DC: The National Academies Press. doi: 10.17226/24936.
×
Page 134
Suggested Citation:"8 All Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2017. Airport Passenger Screening Using Millimeter Wave Machines: Compliance with Guidelines. Washington, DC: The National Academies Press. doi: 10.17226/24936.
×
Page 135
Suggested Citation:"8 All Conclusions and Recommendations." National Academies of Sciences, Engineering, and Medicine. 2017. Airport Passenger Screening Using Millimeter Wave Machines: Compliance with Guidelines. Washington, DC: The National Academies Press. doi: 10.17226/24936.
×
Page 136
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The Transportation Security Administration requested a study by the National Research Council (NRC) to establish the Committee on Airport Passenger Screening: Millimeter Wave Machines to evaluate two models of active millimeter wave scanners: the L3 ProVision 1 and L3 ProVision 2.

Airport Passenger Screening Using Millimeter Wave Machines provides findings and recommendations on compliance with applicable health and safety guidelines and appropriateness of system design and procedures for preventing over exposure. This study addresses the issue of whether millimeter wave machines used at airports comply with existing guidelines and whether it would be possible for anything to go wrong with the machines so that, by mistake, it exposes a person to more than 10 W/m2.

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