ASTM F3278-20

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F3278 − 19a F3278 − 20
Standard Performance Specifications and Test Methods for
Hand-Held Metal Detectors Used in Safety and Security
This standard is issued under the fixed designation F3278; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This standard applies to all hand-held metal detectors (HHMDs) used to find metal contraband concealed or hidden on people
or other objects with accessible surfaces. This standard describes baseline performance requirements, which includes metal object
detection performance, safety (electrical, mechanical, fire), electromagnetic compatibility, environmental conditions and ranges,
and mechanical durability. The requirements for metal detection performance are unique and, therefore, test methods for these
parameters are provided, including the design of test objects. An agency or organization using this standard is encouraged to add
their unique operationally-based requirements to those requirements listed in this baseline performance specification.
1.2 This standard describes the use of spherical test objects, instead of actual threat objects or exemplars of threat objects, to test
the detection performance of hand-held metal detectors. Spherical test objects are used because the detectability of spherical test
objects is not orientation dependent, whereas this is not true for non-spherical test objects. This orientation-dependent detectability
of non-spherical test objects may allow a HHMD to be incorrectly attributed a higher performance capability than that HHMD is
capable of providing. To aid agencies wishing to add specific threat objects to their detection performance requirements, included
in Appendix X1 is the analysis of the probability of detection for different orientations of agency-specific threat objects.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
F3356 Practice for Conformity Assessment of Metal Detectors Used in Safety and Security
2.2 ISO Standards:
ISO 17025:2005 General Requirements for the Competence of Testing and Calibration Laboratories
ISO 10012:2003 Measurement Management Systems – Requirements for Measurement Processes and Measuring Equipment
ISO 14117:2012 Active Implantable Medical Devices – Electromagnetic Compatibility – EMC Test Protocols for Implantable
Cardiac Pacemakers, Implantable Cardioverter Defibrillators, and Cardiac Resynchronization Devices
This standard is under the jurisdiction of ASTM Committee F12 on Security Systems and Equipment and is the direct responsibility of Subcommittee F12.60 on
Controlled Access Security, Search, and Screening Equipment.
Current edition approved Aug. 1, 2019Dec. 1, 2020. Published September 2019December 2020. Originally approved in 2017. Last previous edition approved in 2019 as
F3278 – 19.F3278 – 19a. DOI: 10.1520/F3278-19A.10.1520/F3278-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F3278 − 20
ISO 14708-1:2000 Implants for Surgery – Active Implantable Medical Devices – Part 1: General Requirements for Safety,
Marking and for Information to be Provided by the Manufacturer
ISO 14708-2:2012 Implants for Surgery – Active Implantable Medical Devices – Part 2: Cardiac Pacemakers
ISO 14708-3:2017 Implants for Surgery – Active Implantable Medical Devices – Part 3: Implantable Neurostimulators
ISO 14708-4:2008 Implants for Surgery – Active Implantable Medical Devices – Part 4: Implantable Infusion Pumps
ISO 14708-5:2010 Implants for Surgery – Active Implantable Medical Devices – Part 5: Circulatory Support Devices
ISO 14708-6:2010 Implants for Surgery – Active Implantable Medical Devices – Part 6: Particular Requirements for Active
Implantable Medical Devices Intended to Treat Tachyarrhythmia (Including Implantable Defibrillators)
ISO 14708-7:2013 Implants for Surgery – Active Implantable Medical Devices – Part 7: Particular Requirements for Cochlear
Implant Systems
2.3 IEC Standards:
IEC 61010-1 Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use – Part 1: General
Requirements
IEC 61000-6-1 Electromagnetic Compatibility (EMC) Part 6: Generic Standards – Section 1: Immunity for Residential,
Commercial, and Light-industrial Environments
IEC 61000-4-2 Electromagnetic Compatibilty (EMC) Part 4: Testing and Measurement Techniques – Section 2: Electrostatic
Discharge Immunity Test
IEC 61000-4-3 Electromagnetic Compatibilty (EMC) Part 4: Testing and Measurement Techniques – Section 3: Radiated,
Radio-frequency, Electromagnetic Field Immunity Test
IEC 61000-4-8 Electromagnetic Compatibilty (EMC) Part 4: Testing and Measurement Techniques – Section 8: Power
Frequency Magnetic Field Immunity Test
IEC 60529 2001-2 Degrees of Protection Provided by Enclosures (IP Code)
IEC 60068-2-27:2008-2 Environmental Testing – Part 2-27: Tests – Test Ea and Guidance: Shock
IEC 60068-2-31:2008-05 Environmental Testing – Part 2:31: Tests – Test Ec: Rough Handling Shocks, Primarily for
Equipment-type Specimens
CISPR 22 Information Technology Equipment – Radio Disturbance Characteristics – Limits and Methods of Measurement,
Class B, Radiated Disturbance
2.4 IEEE Standards:
IEEE C95.1 IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3
kHz to 300 GHz
IEEE C95.6 IEEE Standard for Safety Levels with Respect to Human Exposure to Electromagnetic Fields, 0 kHz to 3 kHz
IEEE Std 181-2011 IEEE Standard for Transitions, Pulses, and Related Waveforms
2.5 Military Standards:
MIL-STD-810G Method 501.5 Test Method Standard for Environmental Engineering Considerations and Laboratory Tests,
Method 501.5, High Temperature
MIL-STD-810G Method 502.5 Test Method Standard for Environmental Engineering Considerations and Laboratory Tests,
Method 502.5 Low Temperature
MIL-STD-810G Method 507.5 Test Method Standard for Environmental Engineering Considerations and Laboratory Tests,
Method 507.5, Humidity
2.6 ANSI Standards:
ANSI S1.4-1983 Specification for Sound Level Meters
2.7 CIE Standards:
CIE Standard S 014-1/E:2006 Colorimetry – Part 1: CIE Standard Colorimetric Observers
3. Terminology
3.1 Definitions:
3.1.1 alarm—an indication (which may be audible, visual, or vibratory, or combinations thereof) that informs the operator of an
event, such as metal detection or a detector (HHMD) status change.
3.1.2 body simulant—a material engineered to simulate the average electrical conductivity and magnetic permeability of the
–6
human body. The average electrical conductivity is 0.8 S/m 6 0.2 S/m and the average magnetic permeability is 1.26×10 H ⁄m
–7
6 5×10 H/m.
Available from International Electrotechnical Commission (IEC), 3, rue de Varembé, 1st Floor, P.O. Box 131, CH-1211, Geneva 20, Switzerland, http://www.iec.ch.
Available from Institute of Electrical and Electronics Engineers, Inc. (IEEE), 445 Hoes Ln., Piscataway, NJ 08854-4141, http://www.ieee.org.
Available from U.S. Government Printing Office, Superintendent of Documents, 732 N. Capitol St., NW, Washington, DC 20401-0001, http://www.access.gpo.gov.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
F3278 − 20
3.1.2 detector—the hand-held metal detector (HHMD) that is held in one hand and is used for finding metal objects concealed on
a person or other object.
3.1.3 detector axis—an imaginary line passing through and perpendicular to the detector plane such that the magnetic field around
the detector axis has the maximum symmetry. The detector axis is labeled as the “z” axis. The location of the detector axis relative
to the HHMD shape and geometry is specified by the manufacturer. The detector axis is the reference for positioning in the
detection performance tests. See Fig. 1.
3.1.4 detector holder—a device used to hold the HHMD in place during testing. The detector holder is constructed of
non-ferromagnetic and non-electrically conductive materials.
3.1.5 detector plane—an imaginary plane (two-dimensional surface) that contains the plane, line, or point on the HHMD surface
that is closest to the object being scanned under typical HHMD use and is perpendicular to the detector axis. The detector plane
contains two orthogonal axes labeled as the “x” axis and as the “y” axis. See Fig. 1.
3.1.6 detection sensitivity setting—an adjustment that can be made to the HHMD that affects its ability to sense metal objects.
3.1.7 measurement coordinate system—a mutually orthogonal three-dimensional Cartesian coordinate system referenced to the
detector axis and the detector plane. The three axes are labeled “x,” “y,” and “z,” where the z axis is parallel to the detector axis
and the x axis and the y axis are in the detector plane. The orientation of the test objects is referenced to the measurement
coordinate system. See Fig. 2.
3.1.8 measurement plane—an imaginary two-dimensional surface over which the HHMDs are tested. There may be more than one
measurement plane. The measurement plane(s) is (are) referenced from the detector plane. See Fig. 2. There is a measurement
plane for each size class of the HHMD, as shown in Table 1.
3.1.9 size class—a classification method based on grouping exemplars of commonly encountered objects that may be either
commercially available or readily fabricated from available materials and that are related to customer applications and object sizes.
A HHMD may meet the requirements for one or all size classes, as defined below.
3.1.9.1 large—represents threat items such as handguns, and similarly sized objects, or larger, constructed of ferromagnetic or
nonferromagnetic metal, or both.
3.1.9.2 medium—represents threat items such as knives having blade lengths exceeding 7.5 cm, and similarly sized objects, up
to the size of a large object, constructed of ferromagnetic or nonferromagnetic metal, or both.
3.1.9.3 small—represents threat items such as, but not limited to, knives having blade lengths less than or equal to 7.5 cm,
handcuff keys, handgun rounds, and similarly sized objects, up to the size of a medium object, constructed of ferromagnetic or
nonferromagnetic metal, or both.
FIG. 1 Diagram of Hand-held Metal Detector Showing the Detector Plane (Labeled and Represented by a Rectangle) and the Detector
Axis (Labeled z)
F3278 − 20
FIG. 2 A Diagram of the Measurement Coordinate System Showing the Measurement Coordinate System Axes, One Measurement
Plane, and the Detector Plane. The x axis Points Along the User’s Arm
TABLE 1 Distance Between Measurement Plane and Detector
Plane for the Different HHMD Size Classes
Size Class Distance Between Measurement
Plane and Detector Plane (cm)
Large 8.0 – 0/+ 0.2
Medium 4.0 – 0/+ 0.2
Small 2.0 – 0/+ 0.2
Very Small 0.5 – 0/+ 0.2
3.1.9.4 very small—represents threat items such as t razor blades, hypodermic needles and similarly sized objects, up to the size
of a small object, constructed of ferromagnetic or nonferromagnetic metals, or both.
3.1.10 test object—an item that is used to test the HHMD detection performance. Test objects accurately simulate the
electromagnetic properties of an actual threat or contraband item, such as a weapon or an item that can be used to defeat security
devices. The test objects are described in Section 6.
3.1.11 test object axis—the imaginary line passing through the center of the test object that is referenced to and has a one-to-one
correspondence with the axes of the measurement coordinate system.
3.1.12 x-axis scan range—the segment of line along the x axis of the measurement coordinate system that is centered on the
detector axis and that extends equally on either side of the detector axis.
4. Requirements for Acceptance
NOTE 1—The HHMD shall meet or exceed the requirements and specifications stated in this section. However, it is only to that HHMD unit under test
and at the time of test that a pass/fail assignment can be made with confidence.
NOTE 2—To have confidence that the HHMD unit under test will pass/fail at times other than the time of the initial test or that other units of the same
model will pass/fail requires model evaluation based on a product conformity assessment program, such as that described in Specification F3356 for
F3278 − 20
TABLE 2 X-axis Scan Range for the Different HHMD Size Classes
X-axis Scan Range
Size Class
lower limit (cm) upper limit (cm)
Large –7.5 ± 0.1 7.5 ± 0.1
Medium –6.0 ± 0.1 6.0 ± 0.1
Small –5.7 ± 0.1 5.7 ± 0.1
Very small –5.4 ± 0.1 5.4 ± 0.1
Conformity Assessment of Metal Detectors Used in Safety and Securuity.
NOTE 3—Recommended test report forms are given in Appendix X5.
4.1 General Test Conditions and Requirements:
4.1.1 Testing and Calibration Laboratories—Laboratories performing testing and calibration of the HHMD or its components, or
both, shall meet the requirements of ISO 17025, as amended.
4.1.2 Measurement Equipment and Processes—All measurement equipment and processes shall be certified to ISO 10012, as
amended.
4.2 Safety Specifications and Requirements:
4.2.1 Electrical—The HHMD shall comply with IEC 61010-1, Section 6, “Protection Against Electrical Shock,” as amended.
4.2.2 Mechanical—The HHMD shall meet the requirements of IEC 61010-1 Section 7, “Protection Against Mechanical Hazards,”
as amended.
4.2.3 Thermal—The HHMD shall meet the requirements of IEC 61010-1 Section 10, “Equipment Temperature Limits and
Resistance to Heat,” as amended.
4.2.1 Magnetic Field Exposure—The magnitude of the electromagnetic field generated by the HHMD shall be less than the
8, 9
exposure limits specified for general public exposure in the ICNIRP guidelines (see Appendix X4). These measurements shall
be made at points on grid lines that are (1) tangential to the current-carrying coil of the HHMD and (2) parallel to the surfaces
of an outward projection from the smallest imaginary rectangular prism enclosing that part of the HHMD encasing the
current-carrying coils. The separation, s , between points on these grid lines shall be 5 mm 6 1 mm and between any parallel
grid
tangential lines shall be 5 mm 6 1 mm. The separation between the outward-projected surface and the smallest imaginary
rectangular prism shall be 5 mm 6 1 mm. A three-axis magnetic field probe with a –3 dB analog bandwidth of 0.1f ≤ f ≤ 10f ,
c c c
where f is the nominal center frequency of the generated magnetic field, shall be used for measuring the magnetic field, and the
c
size of its active elements shall be within a volume no larger than 2s × 2s × 2s . If the HHMD has not been demonstrated
grid grid grid
to meet this requirement, the manufacturer shall provide a warning with the HHMD instructions that states “This device has not
been demonstrated as being safe or unsafe for use on people with active implanted or body-worn medical devices, or both.”
4.3 Power Requirement:
4.3.1 Battery Life—The HHMD shall meet the detection performance specification given in 4.4 after operating for at least 10 h
as tested in accordance with 5.55.4 and while using a battery of the type and model recommended by the manufacturer.
4.4 Detection Performance Specifications—The ability of the HHMD to sense the presence of a test object will vary with the
material and geometry of the test object and the distance between the test object and the HHMD. In this performance specification,
the test objects are spherical to avoid the possibility of incorrectly attributing a higher performance capability to a HHMD than
that HHMD is capable of providing. The test objects are grouped according to their size class and the HHMDs are tested for their
ability to detect test objects from within these different size classes. The detection performance specifications shall be tested using
the detection sensitivity setting, if applicable, that is specified by the manufacturer to be appropriate for each test object size class.
ICNIRP “Guidelines for Limiting Exposure to Time-varying Electric, Magnetic, and Electromagnetic Fields (up to 300 GHz),” International Commission on
Non-Ionizing Radiation Protection (ICNIRP), Health Physics, April 1998, Volume 74, No. 4, pp. 494–522.
ICNIRP “Guideline for Limiting Exposure to Time-Varying Electric, Magnetic, and Electromagnetic Fields (1 Hz – 100 GHz), Health Physics, Vol 99 (6), pp. 818–836,
2010.
F3278 − 20
All the tests of 4.45.2, 4.5.35.3, and 4.5.45.4 requirements shall be performed within an 8 h 6 0.5 h period without adjusting the
detector sensitivity setting between tests. The detector sensitivity setting shall not be readjusted during testing, or after changing
the battery. The test objects are given in Section 6.
4.4.1 Detection Sensitivity—The HHMD shall exhibit an average probability of detection, p ≥ 0.95 with an average
d,sens,
confidence level of 0.95 for the test objects in each size class, when each object in the size class is positioned in the appropriate
measurement plane (see Table 1) and moving over the appropriate x-axis scan range (see Table 2) at a speed of 0.5 m ⁄s 6 0.05 m ⁄s
and tested in accordance with 5.2.2. This requirement is met when p ≥ p as computed per 5.2.2.
LB d,sens
4.4.2 Detection Speed—The HHMD shall exhibit an average probability of detection, p ≥ 0.95 with an average confidence
d,sp-sens,
level of 0.95 for the test objects in each size class, when each object in the size class is positioned in the appropriate measurement
plane (see Table 1) and moving over the appropriate x-axis scan range (see Table 2) for each required orientation (see Table 2)
of the test object axes with respect to the measurement coordinate system at a speed of 0.05 m/s 6 0.01 m/s, 0.2 m/s 6 0.01 m/s,
0.5 m/s 6 0.01 m/s, and 1.0 m/s 6 0.01 m/s as tested in accordance with 5.2.2 under the following conditions: (1) the delay
between subsequent tests of a given test object shall be no more than 5 s 6 0.5 s; and (2) the detector sensitivity setting shall not
be readjusted between tests of a given test object or between tests of the test objects of a given size class. This requirement is met
when p ≥ p as computed per 5.2.3.
LB,sp d,sp-sens
4.5 Interference Specifications and Requirements:
4.5.1 Electromagnetic Emission:
4.5.1.1 Radiated Disturbance—The HHMD, when adjusted to meet the requirements of 4.4, shall meet the requirements of CISPR
22, Class B, radiated disturbance.
4.5.2 Electromagnetic Susceptibility/Immunity—The HHMD shall be tested in accordance with the requirements listed in Table 1
of IEC 61000-6-1, as amended, according to the following procedures:
4.5.2.1 Contact Discharge—The HHMD, after being adjusted to meet the requirements of 4.4, shall be tested in accordance with
IEC 61000-4-2, as amended, for Level 2, contact discharge, and ten trials; and shall subsequently meet the requirements of 4.4
without further adjustment and using the limited set of test objects listed in Section 6.
4.5.2.2 Radiated RF Electromagnetic Field Immunity—The HHMD, when adjusted to meet the requirements of 4.4, shall not
produce an alarm when tested in the absence of a test object and in accordance with IEC 61000-4-3, as amended, for Level 2.
4.5.2.3 60 Hz and 50 Hz Radiated Magnetic Field—The HHMD, when adjusted to meet the requirements of 4.4, shall not produce
an alarm when tested in the absence of a test object and in accordance with IEC 61000-4-8, as amended, for testing at 60 Hz and
50 Hz, Level 2, and continuous exposure for 30 min 6 5 min.
4.5.3 Body Interference—The HHMD, without adjusting the detection sensitivity settings used for the tests given in 4.4, shall
exhibit a probability of false alarm, p ≤ 0.05 with a confidence level of 0.95 when operating near the body or body simulant,
fa,b,
as tested in accordance with 5.3. This requirement is met when p ≤ p as computed per 5.3.2 and meets, without adjustment
UB fa,b
of the detector sensitivity, the requirements given in 4.4.
4.5.1 Metal Interference—The HHMD, without adjusting the detection sensitivity settings used for the tests given in 4.4, shall
exhibit a probability of false alarm, p ≤ 0.05 with a confidence level of 0.95 when operating near a large metal plate, as tested
fa,m,
in accordance with 5.45.3. This requirement is met when p ≤ p as computed per 5.4.25.3.2.
UB fa,m
4.6 Environmental Ranges and Conditions—The HHMD or all of its components and their interconnections shall meet all of the
requirements listed in this section. The HHMD shall exhibit no observable changes in the detection performance specification
given in 4.4.2 for the x-axis scan position of 0 cm and using the limited set of test objects listed in Section 6 and the electrical
safety specification given in 4.2.1. The requirements given in this section shall be applied appropriately for either indoor or
indoor/outdoor HHMD models. The tests for the requirements listed in this section shall be performed on the same unit.
4.6.1 Temperature Stability and Range:
4.6.1.1 Indoor—The HHMD shall operate over the ambient temperature range of at least 00 °C to 46°C.46 °C. The HHMD shall
be tested in accordance with MIL-STD-810G Method 501.5, as amended, Procedure II, Steps 1 through 6, relative humidity 6 %
F3278 − 20
6 3 %, at 46°C46 °C 6 3°C.3 °C. The HHMD then shall be cooled to 0°C0 °C 6 3°C3 °C within 4 h 6 0.5 h and tested in
accordance with MIL-STD-810G Method 502.5, as amended, Procedure II, Steps 1 through 7.
4.6.1.2 Indoor/Outdoor—The HHMD shall operate over the ambient temperature range of at least –21°C–21 °C to 65°C.65 °C.
The HHMD shall be tested in accordance with MIL-STD-810G Method 501.5, as amended, Procedure II, Steps 1 through 6,
relative humidity 6 % 6 3 % at 65°C65 °C 6 3°C.3 °C. The HHMD then shall be cooled to –21°C–21 °C 6 3°C3 °C within 4
h 6 0.5 h and tested in accordance with MIL-STD-810G Method 502.5, as amended Procedure II, Steps 1 through 7.
4.6.2 Relative Humidity Stability and Range—The HHMD shall be tested in accordance with the requirements of MIL-STD-810
G Method 507.5, as amended, Procedure I, ten cycles of Cycle B1, as amended.
4.6.2 Ingress Protection:
4.6.2.1 Indoor—The HHMD shall meet or exceed the requirements for compliance with IEC 60529, as amended, classification
IP54.
4.7 Mechanical Specifications and Requirements—The HHMD or all of its components and their interconnections shall meet the
requirements of the following standards. The requirements of 4.2 and 4.4 shall not be affected by the tests described in this section.
All tests listed in this section shall be performed on the same unit. The HHMD shall exhibit no observable changes in the detection
performance specification given in 4.4.24.4.1 for the x-axis scan position of 0 cm and using the limited set of test objects listed
in Section 6 and the electrical safety specification given in 4.2.1.
4.7.1 Shock—The HHMD shall be tested in accordance with the requirements of IEC 60068-2-27:2008, as amended, using 100
6 5 half-sine shock pulses applied to the HHMD along the six directions (1, 0, 0), (0, 1, 0), (0, 0, 1), (–1, 0, 0), (0, –1, 0), and
(0, 0, –1) of the measurement coordinate system and with each shock pulse having a nominal peak acceleration of 40.0 g (392 m/s )
and a nominal pulse duration of 6 ms.
4.7.1 Free Fall—The detector shall be tested in accordance with the requirements of IEC 60068-2-31, Procedure 1, as amended,
for each direction of the detector axes, a fall height of 1 m, and for two drops for each direction of the orthogonal axes depicted
in Fig. 2.
4.8 Alarm Requirements—At least one alarm type, vibratory, audible, or visual, shall be provided and any alarm provided shall
meet the applicable requirement given in this section.
2 2
4.8.1 Vibratory Alarm—The vibratory alarm shall produce an acceleration in the range of 0.2 m/s to 1.0 m/s over a frequency
range of 10 Hz to 300 Hz as measured in accordance with 5.6.1.
4.8.1 Audible Alarm—The audible alarms (other than an earphone), if provided, shall produce an alarm-state sound pressure level
of 75 dB 6 5 dB (where 0 dB = 20 μPa root-mean-square in air) at 0.8 m 6 0.08 m from the HHMD as measured in
SPL SPL
accordance with 5.6.25.5.1. The audible alarm shall be either a frequency-proportional audible alarm or, optionally, a two-state
audible alarm: active (alarm state) and inactive (nonalarm state).
4.8.2.1 Frequency Range—The frequency range of the audible alarm shall be ≥100 Hz and ≤4 kHz as tested in accordance with
5.6.3.
4.8.3 Visual Alarm—The visible alarm, if provided, shall produce an alarm-state light level ≥10 lx when tested in accordance with
5.6.4. The visual alarms shall be a two-state visual alarm: active (illuminating) and inactive (nonilluminating).
4.8.4 Alarm Delays—The maximum delay between activation of all alarms (visual, audible, and vibratory) shall be 200 ms and
the maximum difference in duration among all alarms shall be 200 ms, as tested in accordance with 5.7.
5. Performance Testing Procedures
5.1 General Test Conditions:
5.1.1 Test Location—The distance between any metal object other than a test object (see Section 6) and the closest part of the
HHMD shall be greater than 1.0 m.
F3278 − 20
5.1.2 Environment—At the time of the tests, the ambient temperature shall be in the range specified in 4.6 for the appropriate
application (indoor or indoor/outdoor); the relative humidity shall be noncondensing.
5.1.3 Preparations—New or fully-charged batteries of the type listed in the operator’s manual shall be installed at the beginning
of the tests and as instructed in any test method. Any setup or calibration adjustments specified in the operator’s manual shall be
performed if required. In any stand-by feature is available on the HHMD, this feature shall be disabled.
5.2 Detection Performance Tests—The detection performance test methods described in this section are based on the use of a
computer-controlled three-axis positioning system to control the motion and displacement of the test object relative to the HHMD.
Other means of controlling this motion and displacement are acceptable if the positioning and speed values are within the
tolerances specified in these test methods. If the HHMD can be adjusted to provide an alarm for more than one size class, the
detection performance test shall be performed for each size class. The detection performance shall be evaluated by the test methods
described in this section. The distinction in testing between the different size classes is the difference in the test separation distance
between the measurement plane and the detector plane.
5.2.1 Measurement System—The measurement system shall contain the components necessary to perform the tests described
herein. A diagram of the measurement system showing the electrical and mechanical connections between its components shall be
provided.
5.2.2 Detection Sensitivity Test:
5.2.2.1 Initial Procedures:
(1) Turn on the measurement system and verify proper operation of the measurement system.
(2) Ensure that the HHMD is securely fixed to the detector holder and that the detector holder is fixed in position and secured
to the measurement system.
(3) Attach the test object to the positioning component of the measurement system.
(4) Turn on the HHMD and ensure that its output is functioning properly by noting a change in the alarm output as a metal
object is brought near the HHMD.
(5) Ensure that the test object does not hit the detector holder or any other objects while in motion.
(6) There is a minimum number of repeats of a given measurement that must be performed to meet the performance
requirements for a given confidence interval. This minimum number of measurements, N , is given by:
T
z p
c 0
N 5 ceil (1)
H J
T
12 p
where p is equal to the probability of detection specified in 4.4.2; z is the critical point of a standard normal distribution and
0 c
is fixed for a given confidence interval; and ceil{x} is a function that returns the smallest integer value that is greater than x.
The value of N includes the number of test objects of a given test object class, and the number of scans performed. For
T
example, when p = 0.95 and the confidence level = 0.95, N = 52. Values of N are provided for convenience in Appendix
0 T T
X3.
(7) Determine the number, n of y-axis scans to perform at each x-axis position for a given test object and given the number,
s,k,
n , of practicable x-axis positions, and the total number of required scans, N . The values of n is computed using:
x T s,k
N
T
n 5 max , 10 , (2)
H J
s,k
n
x
where the function max{x,y} returns the maximum value of x and y.
5.2.2.2 Performing the Measurement:
(1) Prepare the measurement system to perform an x-y scan in the specified measurement plane at the specified speed. The
center for the y-axis scans shall be the detector axis and the y-axis scans shall each be no less than 40 cm 6 1 cm long.
(2) Set the x-axis position to the specified lower x-axis scan range limit.
(3) Scan the y axis and record any alarm as the y-axis scan is being performed.
(4) Repeat Step (3) n times to perform a total of n scans for the current x-axis scan position.
s,k s,k
(5) Compute the probability of alarm, p , where x is the x-axis scan position and i is the x-axis scan index, and obj
d,sens,obj x i k
k, i
represents the test object of the given test object size class with index k, using:
n
s,k
p 5 A (3)
d,sens,k,i ( Pos2sens,k,i,j
n
j51
s,k
F3278 − 20
where the index abbreviations: k = obj , and i = x are used and A is an integer value representing the occurrence of
k i Pos-sens,k,i,j
the alarm (0 for the nonalarm state and 1 for the alarm state) for each x-axis scan position.
(6) Increment the x-axis position by 0.5 cm 6 0.1 cm.
(7) Repeat Steps (3) through (6) until the x-axis position is at the specified upper x-axis scan range limit and record the number
of alarms at each x and N is the number of x-axis positions scanned.
i x
(8) Repeat Step (7) for each of the remaining K–1 – 1 test objects of a given size class, where K is the number of test objects
in the size class.
(9) Upon completion of Step (8), compute the average probability of detection, p using:
d,sens,
K N
x
p 5 p . (4)
d,sens (( d,sens,k,i
KN
k51i51
x
(10) Compute and record the average lower bound, p , of p using:
LB d,sens
K N
x
Σ Σ ~p 2 l !
Œ
d,sens,k,i k,i
k51i51
p 5 p 2 , (5)
LB d,sens
KN
x
where
z
c
p ~1 2 p !1
k,i k,i
z 4n
c k,i
p 10.5 2 z
!
k,i c
n n
k,i k,i
l 5 , (6)
k,i 2
z
c
n
k,i
where for these tests n = n as computed in 5.2.2.1. For a 95 % confidence interval, z = 1.645 and for a 99 % confidence
k,i s,k c
interval, z = 2.576.
c
(11) Set p = P , and report this value.
d LB
5.2.3 Detection Speed Test:
5.2.3.1 Initial Procedures:
(1) Turn on the measurement system and verify proper operation of the measurement system.
(2) Ensure that the HHMD is securely fixed to the detector holder and that the detector holder is fixed in position and secured
relative to the positioning component of the measurement system.
(3) Turn on the HHMD and ensure that its output is functioning properly by noting a change in the alarm output as a metal
object is brought near the HHMD.
(4) Ensure that the test object does not hit the detector holder or any other objects while in motion.
(5) Use the value of N computed in Eq 1.
T
(6) Determine the number, n of y-axis scans to perform at each x-axis position for a given test object and given the number,
s,k,
n , of practicable x-axis positions, the number, and the total number of required scans, N . The value of n is computed using:
x T s,k
N
T
n 5 max , 10 , (7)
H J
s,k
n
x
where the function max{x,y} returns the maximum value of x and y.
5.2.3.2 Performing the Measurement:
(1) Prepare the measurement system to perform an x-y scan in the specified measurement plane at the specified speed. The
center for the y-axis scans shall be the detector axis and the scans shall each be no less than 40 cm 6 1 cm long.
(2) Set the x-axis position to the specified lower x-axis scan range limit.
(3) Scan the y axis and record any alarm as the y-axis scan is being performed.
(4) Repeat Step (3) n times to perform a total of n scans for the current x-axis scan position.
s,k s,k
(5) Compute the probability of alarm, p , where x is the x-axis scan position and i is the x-axis scan index, obj
d,sens,obj x s i k
k, i, m
represents the test object of the given test object size class with index k, and s represents the different speeds with index m, using:
m
n
s
p 5 A (8)
d,sens,k,i,m ( Pos2sens,k,i,m,j
n
j51
s
where the index abbreviations: k = obj ,i = x , and m = s are used and A is an integer value representing the oc-
k i m Pos-sens,k,i,m,j
currence of the alarm (0 for the nonalarm state and 1 for the alarm state) for each x-axis scan position.
(6) Increment the x-axis position by 0.5 cm 6 0.1 cm.
(7) Repeat Steps (3) through (6) until the x-axis position is at the specified upper x-axis scan range limit and record the number
of alarms at each x , and N is the number of x-axis positions scanned.
i x
F3278 − 20
(8) Repeat Step (7) for each of the remaining K-1 – 1 test objects of a given size class, where K is the number of test objects
in a given size class.
(9) Repeat Step (8) for each of the M test speeds.
(10) Upon completion of Step i, compute the average probability of detection, p using:
d,sp-sens,
K N M
1 x
p 5 Σ Σ Σ p . (9)
d,sp2sens d,sens,k,i,m
KN M
k51i51m51
x
(11) Compute the average lower bound, p of
LB,sp,
p using:
d,sp-sens
K N M
x
Σ Σ Σ ~p 2 l !
Œ
d,sens,k,i,m k,i,m
k51i51m51
p 5 p 2 , (10)
LB,sp d,sp2sen
KN M
x
where:
z
c
p ~1 2 p !1
2 k,i,m k,i,m
z 4n
c k,i,m
p 10.5 2 z
!
k,i,m c
n n
k,i,m k,i,m
l 5 , (11)
k,i,m 2
z
c
n
k,i,m
where for these tests n = k as computed in 5.2.2.1. For a 95 % confidence interval, z = 1.645 and for a 99 % confidence
k,i,m s,k c
interval z = 2.576.
c
(12) Record and report p .
LB,sp
5.3 Body Interference Test—This test may be performed using a body simulant test object or a clean torso. A clean torso is defined
here as the torso of a person that is free of any metal objects.
5.3.1 Initial Procedures:
(1) The body simulant test object, if used, shall be constructed of a material exhibiting an electrical conductivity of 0.8 S/m
–6 –7
6 0.2 S/m and magnetic permeability of 1.26×10 H ⁄m 6 5×10 H/m and be a rectangular prism with a thickness (direction
parallel to z axis) of 3 cm 6 0.5 cm, a length (direction parallel to x axis) of 20 cm 6 0.5 cm, and a width (direction parallel to
y axis) of 10 cm 6 0.5 cm.
(2) Use the value of N computed in Eq 1.
T
(3) Turn on the measurement system and verify proper operation of the measurement system. Ensure that the HHMD is
securely held by a clean hand, which is a hand free of any metal, from the tips of the fingers of that hand to the elbow of the same
arm as the hand being used. Turn on the HHMD and ensure that its output is functioning properly by noting a change in the alarm
output as a metal object is brought near the HHMD.
5.3.2 Performing the Measurement:
(1) Sweep the HHMD over the body simulant test object or clean torso at a velocity of approximately 1 m/s while maintaining
an approximate separate of 5 mm between the HHMD and the body simulant or clean torso and record any alarms.
(2) Repeat Step (1) N – 1 times to yield a total of N scans and compute the average alarm occurrence using:
T T
N
T
p 5 A , (12)
fa,b ( Pos2b,j
N
j51
T
where A is an integer value representing the occurrence of the alarm (0 for the nonalarm state and 1 for the alarm state),
Pos-b,j
j is the scan repeat index, and p is the probability of false alarm for the body interface test.
fa,b
(3) Compute the upper bound, p , of p using:
UB fa,b
z
c
p ~1 2 p !1
2 fa,b fa,b
z 4N
c T
p 10.5 1z
!
fa,b c
N N
T T
p 5 (13)
UB 2
z
c
N
T
and record and report this value.
5.3 Metal Interference Test:
5.3.1 Initial Procedures:
F3278 − 20
(1) The metal test panel shall be cold-finished sheet carbon steel UNS G10150 to G10200, 1 m 6 0.1 m by 1 m 6 0.1 m by
0.75 mm 6 0.13 mm thick. The panel shall be mounted or supported in a manner that keeps the panel flat.
(2) Use the value of N computed in Eq 1.
T
5.3.2 Performing the Measurement:
(1) Position the HHMD with its detector plane parallel to and 0.5 m 6 0.05 m from the plane of the test panel and with the
detector axis centered with respect to the center of the test panel. Parallel is 0° 6 1°. Turn on the HHMD and without changing
the HHMD performance settings note and perform a y-axis scan across the detector axis using the same parameters as in 5.2.2.
Record any alarms. Repeat this y-axis scan N – 1 times to yield a total of N scans and compute the average alarm occurrence
T T
using:
N
T
p 5 A , (12)
fa,m Pos2m,j
(
N
T j51
where A is an integer value representing the occurrence of the alarm (0 for the nonalarm state and 1 for the alarm state),
Pos-m,j
j is the scan repeat index, and p is the probability of false alarm for the metal interference test.
fa,m
(2) Compute the upper bound, p , of p using:
UB fa,m
z
c
p 1 2 p 1
~ !
fa,m fa,m
z 4N
c T
p 10.5 1z
!
fa,m c
N N
T T
p 5 . (13)
UB 2
z
c
N
T
F3278 − 20
5.4 Battery Life Test:
5.4.1 Initial Procedures:
(1) Install in the HHMD new or fully charged batteries of the type specified by the manufacturer.
(2) Ensure that the alarm detector and positioning system are connected to the computer controller.
(3) Turn on the measurement system and verify proper operation of the measurement system.
(4) Ensure that the HHMD is securely fixed to the detector holder and that the detector holder is fixed in position and secured
relative to the positioning component of the measurement system.
(5) Attach the test object with the proper orientation to the positioning system.
(6) Turn on the HHMD and ensure that its output is functioning properly by noting a change in the alarm output as a metal
object is brought near the HHMD.
(7) Ensure that the test object does not hit the detector holder or any other objects while in motion.
5.4.2 Performing the Measurement:
(1) Prepare the measurement system to perform a series of y scans of a large size test object in the measurement plane for a
large size test object at a speed of about 0.5 m/s. The center for the y-axis scans shall be the detector axis and the scans shall each
be approximately 40 cm long. The duration of this series of scans shall be 10 h 6 0.1 h. The delay between scans shall be 30 s
6 2 s.
(2) After completion of Step (1), perform ten y scans of a small size test object in the measurement plane for a small size test
object at a speed of about 0.5 m/s. The center for the y-axis scans shall be the detector axis and the scans shall each be
approximately 40 cm long. The delay between scans shall be less than 2 s. Compute the alarm rate, r , using:
alarm
N
alarms
r 5 , (14)
alarm
where N is the number of alarms that were observed in step b.
alarms
(3) If r ≥ p , then record and report this as passing the battery life requirement, otherwise record and report as not
alarm d,sens
passing the battery life requirement.
5.5 Alarm Tests:
5.6.1 Vibratory Alarm Test:
(1) Place vibration detector in contact with that part of the HHMD closest to the component that produces the vibratory alarm.
(2) Measure the vibration of the vibratory alarm in all three orthogonal Cartesian directions with the HHMD power applied
and the alarm in the nonalarm state and compute the vibration magnitude, v , as the vector norm (L2 norm) of these
na
measurements.
(3) Cause the HHMD to produce an alarm, and again measure and record the vector norm of the vibration magnitude, v .
na+a
(4) Compute the different between two vibration magnitudes, using:
v 5 v 2 v , (17)
a na1a na
where v is the vibration magnitude produce by the alarm.
a
(5) Repeat this measurement five times and calculate the average value of v .
a
(6) Record and report the average value.
5.5.1 Audible Alarm Test:
(1) Perform the test in an anechoic chamber. Position the sound pressure meter 0.80 m 6 0.02 m from the HHMD.
(2) Measure the sound pressure level, P , with the HHMD power applied and the alarm in the nonalarm state.
na
(3) Cause the HHMD to produce an alarm, and again measure and record the sound pressure level, P . Compute the sound
na+a
pressure level generated by the alarm, P , using:
a
P P
na1a na
P 5 10log ~10 10 2 10 10 !. (15)
a 10
(4) Repeat this measurement five times and calculate the average value of P .
a
(5) Record and report the average P .
a
(6) For frequency proportional alarms, P shall be measured and reported at the following frequencies within the frequency
a
band of the audible signal: lowest operational limit, f , of the audible alarm frequency band; highest operational limit, f , of the
low hi
audible alarm frequency bands; and the middle frequency, f , where
mid
f 1f
hi low
f 5 . (16)
mid
F3278 − 20
5.6.3 Audible Alarm Frequency Range Test:
(1) Perform the test in an anechoic chamber.
(2) Position the sound pressure meter 0.80 m 6 0.02 m from the HHMD and connect this device to an audio frequency
measurement system.
(3) Turn the HHMD power on and cause the HHMD to produce an alarm.
(4) Repeat this measurement five times and calculate the average value of the audio frequency.
(5) Record and report the average audio frequency measured by the audio frequency measurement system.
5.6.4 Visual Alarm Test:
(1) Position the HHMD 0.80 m 6 0.02 m from in contact with the illumination meter, with the line perpendicular (90° 6 5°)
to the plane of the input aperture of the illumination meter and the line perpendicular (90° 6 5°) to the output aperture of the visual
alarm nominally collinear.
(2) Perform the test at a location where the ambient illumination is 1000 lx 6 100 lx.
(3) Turn on the HHMD and move a metal object near the HHMD to cause an alarm.
(4) Measure the light level, E , with the HHMD power applied and the alarm in the nonalarm state.
na
(5) Cause the HHMD to produce an alarm, and again measure and record the light level, E .
na+a
(6) Compute the light level increase, E , due to the alarm indicator using:
a
E 5 E 2E . (20)
a na1a na
(7) Repeat this measurement five times and calculate the average value of E .
a
(8) Record and report the average value.
5.7 Alarm Decay Test—Activation of an alarm shall be defined as the instant the alarm has increased to half its amplitude, where
the amplitude is defined as the difference between the high (alarm state) and low (no alarm state) output of the alarm. Deactivation
of an alarm shall be defined as the instant the alarm has decreased to half its amplitude. The duration of the alarm is defined as
the difference between its first an
...