ASTM C1309-97

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: C 1309 – 97
Standard Practice for
Performance Evaluation of In-Plant Walk-Through Metal
Detectors
This standard is issued under the fixed designation C 1309; 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 (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Nuclear regulatory authorities require personnel entering designated security areas to be screened
for concealed weapons and personnel exiting areas containing specified quantities of special nuclear
material to be screened for metallic nuclear shielding materials. Portal-type walk-through metal
detectors are widely used to implement these requirements. This practice provides guidelines for
evaluating the in-plant performance of walk-through metal detectors.
1. Scope interferences or the perturbation of the detection field by the
tester’s body mass.
1.1 This practice is one of several (see Appendix X1)
1.2.3.1 This procedure also can be used to establish a
developed to assist operators of nuclear facilities with meeting
probability of occurrence for false alarms, for example, 20 test
the metal detection performance requirements set by regulatory
passes by a clean-tester resulting in no alarms indicates a false
authorities.
alarm probability of less than 0.15 at 95 % confidence. This
1.2 This practice consists of four procedures useful for
procedure is optional unless required by the regulatory author-
evaluating the in-plant performance of walk-through metal
ity.
detectors (see Fig. 1).
1.3 This practice does not set test object specifications. The
1.2.1 Two of the procedures provide data for evaluating
specifications should be issued by the regulatory authority.
probability of detection. These procedures use binomial data
1.4 This practice is intended neither to set performance
(alarm/not alarm).
levels nor to limit or constrain technologies.
1.2.1.1 The detection sensitivity test (DST) is the initial
1.5 This practice does not address safety or operational
procedure in the detection probability evaluation series. It is
issues associated with the use of walk-through metal detectors.
used to establish the probability of detection immediately after
the detector has been adjusted to its operational sensitivity
2. Referenced Documents
setting.
2 2.1 ASTM Standards:
1.2.1.2 The detection sensitivity verification test (DSVT)
C 1238 Guide for Installation of Walk-Through Metal De-
procedure periodically provides data for evaluation of continu-
tectors
ing detection performance.
C 1269 Practice for Adjusting the Operational Sensitivity
1.2.2 The third procedure is a “functional test.” It is used
Setting of In-Plant Walk-Through Metal Detectors
routinely to verify that a metal detector is operating and
C 1270 Practice for Detection Sensitivity Mapping of In-
responds with the correct audio and visual signals when
Plant Walk-Through Metal Detectors
subjected to a condition that should cause an alarm.
F 1468 Practice for Evaluation of Metallic Weapons Detec-
1.2.3 The fourth procedure is used to verify that alarms
tors for Controlled Access Search and Screening
generated during detection sensitivity testing were likely the
result of the detection of metal and not caused by outside
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 clean-tester, n—a person who does not carry any
This practice is under the jurisdiction of ASTM Committee C-26 on Nuclear
extraneous metallic objects that would significantly alter the
Fuel Cycle and is the direct responsibility of Subcommittee C26.12 on Safeguard
signal produced when the person carries a test object.
Applications.
3.1.1.1 Discussion—By example but not limitation, such
Current edition approved Dec. 10, 1997. Published February 1998. Originally
published as C 1309 – 95. Last previous edition C 1309 – 95.
extraneous metallic objects may include: metallic belt buckles,
The DST is one of two procedures used to evaluate detection rate. The
Detection Sensitivity Verification Test (DSVT) is the other. In the evaluation test
strategy, the DST is used to initially determine and document the detection rate and
then the DSVT is used to periodically check that the detection rate continues to meet Annual Book of ASTM Standards, Vol 12.01.
the requirements. Annual Book of ASTM Standards, Vol 15.07.
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
C 1309
NOTE 1—The number of detection sensitivity verification tests in a series, the number of passes per test, the acceptance criteria, and the frequency may
be established by regulatory authority or set by the security organization based on threat scenarios or vulnerability assessments; the numbers should be
sufficient to provide a degree of assurance commensurate with the detector application.
NOTE 2—If the detector fails to meet the acceptance criteria, the verification series is terminated. The detector then must be tested to reestablish the
probability of detection. If the probability of detection requirement cannot be met (repairs may be necessary), the detector must be mapped and the
operational sensitivity setting reestablished. Performance testing can then be resumed starting with a new detection sensitivity test.
NOTE 3—If the detector fails the functional test, the detector must be immediately removed from service (see Appendix X1).
FIG. 1 Walk-Through Metal Detector Evaluation Testing Program
metal buttons, cardiac pacemakers, coins, metal frame eye- elimination of extraneous metal to obtain less than 10 % signal
glasses, hearing aids, jewelry, keys, mechanical pens and disturbance. The tester shall have a weight between 50–104 kg
pencils, shoes with metal shanks or arch supports, metallic and a height between 1.44–1.93 m. Should a given detector be
surgical implants, undergarment support metal, metal zippers, sensitive to body size because of design or desired sensitivity,
etc. In the absence of other criteria, a clean-tester passing the physical size of testers should be smaller and within a
through a metal detector shall not cause a disturbance signal narrower range. It is recommended that the clean-tester be
greater than 10 % of that produced when carrying the critical surveyed with a high sensitivity hand-held metal detector to
test object through the detector. Test objects requiring very ensure that no metal is present.
high sensitivity settings for detection require more complete 3.1.2 critical orientation, n—the orthogonal orientation of a
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
C 1309
test object that produces the smallest detection signal or
weakest detection anywhere in the detection zone; the orthogo-
nal orientation of a test object that requires a higher sensitivity
setting to be detected compared to the sensitivity settings
required to detect the object in all other orthogonal orienta-
tions. See Fig. 2 for handgun orientations.
3.1.2.1 Discussion—Critical orientations are determined by
testing using a mapping procedure such as described in
Practice C 1270 (see 3.1.21 and Fig. 3).
3.1.2.2 Discussion—The term critical orientation can be
applied in two ways. Critical orientation can refer to the worst
case orthogonal orientation in a single test path or the worst
case orthogonal orientation for all the test paths (the entire
detection zone). The two are coincident in the critical test path.
3.1.3 critical sensitivity setting, n—the lowest sensitivity
setting of a detector at which the critical test object in its
critical orientation is consistently detected (10 alarms out of 10
passages) when passed through the detection zone on the
critical test path.
3.1.4 critical test element, n—see test element.
NOTE 1—Numbers are sensitivity setting values for a hypothetical
3.1.5 critical test object, n—the one test object out of any
detector. The numbers represent the lowest sensitivity setting at which the
given group of test objects that, in its critical orientation,
object was detected ten out of ten consecutive test passes through the
produces the weakest detection signal anywhere in the detec- indicated test path.
FIG. 3 Example of Detection Sensitivity Map
tion zone.
3.1.5.1 Discussion—The group referred to consists of one
or more objects that are to be detected at the same detector
setting.
3.1.5.2 Discussion—Depending on the particular detector,
some orientation-sensitive test objects may have different
critical orientations through different test paths in the detection
zone. Hence, care must be taken in determining the critical test
object, its critical orientation, and the critical test path.
3.1.6 critical test path, n—the straight-line shortest-course
path through the portal aperture, as defined by an element on
the detection sensitivity map, that produces the smallest
detection signal or weakest detection for a test object in its
critical orientation (see Fig. 4 and Fig. 2).
3.1.7 detection sensitivity map (see Fig. 3 and Appendix
X2), n—a depiction of the grid used to define test paths
through the detection zone, with each element of the grid
containing a value, usually the sensitivity setting of the
detector, that is indicative of the detectability of the test object.
FIG. 4 3-D View of Detection Zones and Test Grid
3.1.7.1 Discussion—These values are relative and describe
the detection sensitivity pattern within the detection zone for
the specific test object. The values are derived by identically
testing each defined test path using a specific test object in a
single orthogonal orientation. The value is usually the mini-
mum sensitivity setting of the detector that will cause a
consistent alarm (10 out of 10 test passes when the test object
is passed through the detection field. Appendix X2 is a sample
form for a potential detection sensitivity map configuration.)
FIG. 2 Six Standard Orthogonal Orientations for a Handgun 3.1.8 detection sensitivity test, n—see 6.2.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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C 1309
3.1.9 detection sensitivity verification test, n—see 6.3. as the longitudinal axis. Fig. 2 illustrates the six standard
orthogonal orientations for a handgun.
3.1.10 detection zone, n—the volume within the portal
aperture.
3.1.22 performance test log, n—a record of the operation,
3.1.11 detector, n—see walk-through metal detector. testing, and maintenance history of a metal detector.
3.1.12 element, n—see test element. 3.1.22.1 Discussion—Appendix X4, Performance Test Log,
3.1.13 event false alarm, n—an alarm occurring when a suggests examples for log content and format.
clean-tester, while not carrying a test object, passes through the 3.1.23 portal, n—see walk-through metal detector.
detection zone of a detector operating at the operational
3.1.24 shielding test object, n—a test object representing
sensitivity setting.
special nuclear material shielding that might be used in a theft
3.1.14 event false alarm test, n—see 6.4. scenario.
3.1.15 functional test, n—see 6.1. 3.1.24.1 Discussion—It is usually a metallic container or
3.1.16 functional test object, n—a metallic item that does metallic material configured as a credible gamma radiation
not necessarily have strict criteria defining its size, form, shield for a specific type and quantity of special nuclear
weight, or composition. material. The object is specified by a regulatory authority or is
based on the facility threat/risk assessment, or both
3.1.16.1 Discussion—Functional test objects do not test
sensitivity; they are gross stimuli used frequently to quickly 3.1.25 test element, n—(see Fig. 1) for the purpose of
verify that the aural and visual indicators and alarm circuits are testing, it is necessary to define discrete and repeatable
operable. straight-line shortest-course test paths through the detection
3.1.16.2 Discussion—A functional test object will consis- zone. This can be done by using two identical networks (grids)
tently cause metal detection alarms when a detector is adjusted made of nonconductive/nonmagnetic material attached across
to detect the critical test object in its critical orientation passing the entry and exit planes of the portal aperture so the networks
through the critical test path. Detection of the functional test coincide. A test object on the end of a probe can then be passed
object does not provide assurance that the detector is operating from one side of the portal aperture to the other side through
properly or adjusted to detect anything other than the func- corresponding openings, which results in the test object taking
tional test object. a reasonably straight-line shortest-course path through the
detection zone. If the networks are constructed so that they can
3.1.16.3 Discussion—Functional test objects may be items
be put in-place identically each time they are used, then the test
such as large handguns or rifles, metal tools, metal blocks, a
paths through the detection zone are repeatable over time.
person wearing many metallic items, etc. Active devices such
Thus, a test element is the volume of space defined by the
as radios and pagers must not be used as functional test objects
boundaries of two corresponding network openings and it
and must not be carried when performing tests. The functional
represents a straight-line shortest-course path through the
test object must be at least as detectable as the critical test
detection zone.
object in its critical orientation.
3.1.25.1 Discussion—On a detection sensitivity map the
3.1.17 grid, n—see test grid
corresponding networks appear as a rectangular grid with each
3.1.18 grid element, n—(1) a single block on a detection
element of the grid representing a test path through the
sensitivity map; (2) the rectilinear volume through the detec-
detection zone. The element defining the critical test path is the
tion zone defined by coincident elements of identical grid
critical test element.
works placed on either side of the portal aperture. (See Figs. 3
3.1.26 test grid, n—a network of nonconductive/non-
and 4)
magnetic material, such as string or tape, can be stretched
3.1.18.1
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