ASTM C1270-97

Standard Practice for Detection Sensitivity Mapping of In-Plant Walk-Through Metal Detectors

SCOPE
1.1 This standard practice covers a procedure for determining the weakest detection path through the portal aperture and the worst-case orthogonal orientation (Note 1) of metallic test objects. It results in detection sensitivity maps, which model the detection zone in terms related to detection sensitivity and identify the weakest detection paths. Detection sensitivity maps support sensitivity adjustment and performance evaluation procedures (see Practice C1269).  Note 1-As used in this practice, orthogonal orientation refers to alignment of the longitudinal axis of a test object along the XYZ axes of the Cartesian coordinate system; is horizontal and across the portal, is vertical, and is in the direction of travel through the portal. Note 2-Unsymmetrical metal objects possessing a primary longitudinal component, such as handguns and knives, usually have one particular orientation that produces the weakest detection signal. The orientation and the path through the detector aperture where the weakest response is produced may not be the same for all test objects, even those with very similar appearance. Note 3-In the case of multiple specified test objects or for test objects that are orientation sensitive, it may be necessary to map each object several times to determine the worst-case test object or orientation, or both.
1.2 This practice is one of several developed to assist operators of walk-through metal detectors with meeting the metal detection performance requirements of the responsible regulatory authority.
1.3 This practice is neither intended to set performance levels, nor limit or constrain operational technologies.
1.4 This practice does not address safety or operational issues associated with the use of walk-through metal detectors.
1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

General Information

• Status: Historical
• Publication Date: 09-Dec-1997
• Technical Committee: C26 - Nuclear Fuel Cycle

Relations

• Replaced By: ASTM C1270-97(2003) - Standard Practice for Detection Sensitivity Mapping of In-Plant Walk-Through Metal Detectors
• Effective Date: 10-Dec-1997

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.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 1270 – 97
Standard Practice for
Detection Sensitivity Mapping of In-Plant Walk-Through
Metal Detectors
This standard is issued under the fixed designation C 1270; 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. Additionally, in security areas containing specified quantities of special
nuclear materials, exiting personnel are required to be screened for metallic nuclear shielding material.
Walk-through metal detectors are widely used to implement these requirements.
A number of environmental conditions, architectural and electrical arrangements near the detector,
and detector characteristics affect the detection of metallic objects passing through the walk-through
metal detector. These external effects and detector characteristics are discussed in Practices F 1468 and
C 1269, and Guide C 1238. This practice is intended to minimize the effects of these variables on
detector operation by providing the operator with baseline information on the metal detection
sensitivity within the portal aperture, particularly the location of any weak areas of detection. The data
is obtained by mapping the detection zone (volume within the portal) of each detector at its field
location, under normal operating conditions, and using the target test object. The maps, when applied
to detector operation, ensure that the effects of the fixed environmental conditions, architectural and
electrical arrangements, and detector characteristics are taken into account during operational
sensitivity adjustment, performance evaluation, and general operation of detectors.
1. Scope metal detection performance requirements of the responsible
regulatory authority. (See Appendix X2)
1.1 This standard practice covers a procedure for determin-
1.3 This practice is neither intended to set performance
ing the weakest detection path through the portal aperture and
levels, nor limit or constrain operational technologies.
the worst-case orthogonal orientation of metallic test objects. It
1.4 This practice does not address safety or operational
results in detection sensitivity maps, which model the detection
issues associated with the use of walk-through metal detectors.
zone in terms related to detection sensitivity and identify the
1.5 The values stated in SI units are to be regarded as the
weakest detection paths. Detection sensitivity maps support
standard. The values given in parentheses are for information
sensitivity adjustment and performance evaluation procedures
only.
(see Practices C 1269 and C 1309).
NOTE 1—Unsymmetrical metal objects possessing a primary longitudi- 2. Referenced Documents
nal component, such as handguns and knives, usually have one particular
2.1 ASTM Standards:
orientation that produces the weakest detection signal. The orientation and
C 1238 Guide for Installation of Walk-Through Metal De-
the path through the detector aperture where the weakest response is
tectors
produced may not be the same for all test objects, even those with very
C 1269 Practice for Adjusting the Operational Sensitivity
similar appearance.
NOTE 2—In the case of multiple specified test objects or for test objects Setting of In-Plant Walk-Through Metal Detectors
that are orientation sensitive, it may be necessary to map each object
C 1309 Practice for Performance Evaluation of In–Plant
several times to determine the worst-case test object or orientation, or
Walk–Through Metal Detectors
both.
F 1468 Practice for the Evaluation of Metallic Weapons
1.2 This practice is one of several developed to assist
Detectors for Controlled Access Search and Screening
operators of walk-through metal detectors with meeting the
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
This practice is under the jurisdiction of ASTM Committee C26 on Nuclear
Fuel Cycle and is the direct responsibility of Subcommittee C26.12 on Safeguard
Applications. Annual Book of ASTM Standards, Vol 12.01.
Current edition approved Dec. 10, 1997. Published June 1998. Annual Book of ASTM Standards, Vol 15.07.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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 1270
3.1.1 clean-tester, n—a person who does not carry any passes) when passed through the detection zone on the critical
extraneous metallic objects that would significantly alter the test path.
signal produced when the person carries a test object. 3.1.4 critical test element, n—see test element.
3.1.1.1 Discussion—By example but not limitation, such 3.1.5 critical test object, n—see test object.
extraneous metallic objects may include: metallic belt buckles, 3.1.6 critical test path, n—the straight-line shortest-course
metal buttons, cardiac pacemakers, coins, metal frame eye path through the portal aperture, as defined by an element on
glasses, hearing aids, jewelry, keys, mechanical pens and the detection sensitivity map, that produces the smallest
pencils, shoes with metal shanks or arch supports, metallic detection signal or weakest detection for a test object in its
surgical implants, undergarment support metal, metal zippers, critical orientation. (see Figs. 2 and 3)
etc. In the absence of other criteria, a clean tester passing 3.1.7 detection sensitivity map, n—(see Figs. 2 and 1) a
through a metal detector shall not cause a disturbance signal depiction of the grid used to define test paths through the
greater than 10 % of that produced when carrying the critical detection zone, with each element of the grid containing a
test object through the detector. Test objects requiring very value, usually the sensitivity setting of the detector, that is
high sensitivity settings for detection require more complete indicative of the detectability of the test object.
elimination of extraneous metal to obtain less than 10 % signal 3.1.7.1 Discussion—These values are relative and describe
disturbance. the detection sensitivity pattern within the detection zone for
3.1.1.2 Discussion—The tester shall have a weight between the specific test object. The values are derived by identically
50 to 104 kg (110 to 230 lb) and a height between 1.44 to 1.93 testing each defined test path using a specific test object in a
m (57 to 75 in.). Should a given detector be sensitive to body single orthogonal orientation. The value is usually the mini-
size because of design or desired sensitivity, the physical size mum sensitivity setting of the detector that will cause a
of testers should be smaller and within a narrower range. consistent alarm (10 out of 10 test passes) when the test object
3.1.1.3 Discussion—It is recommended that the clean tester is passed through the detection field. Appendix X3 is a sample
be surveyed with a high sensitivity hand-held metal detector to form for a potential detection sensitivity map configuration.
ensure that no metal is present. 3.1.8 detection zone, n—the volume within the portal aper-
3.1.2 critical orientation, n—the orthogonal orientation of a ture.
test object that produces the smallest detection signal or 3.1.9 detector, n—see walk-through metal detector.
weakest detection anywhere in the detection zone; the orthogo- 3.1.10 element, n—see test element
nal orientation of a test object that requires a higher sensitivity 3.1.11 grid, n—see test grid
setting to be detected compared to the sensitivity setting 3.1.11.1 grid element, n—(1) a single block on a detection
required to detect the object in all other orthogonal orienta- sensitivity map; (2) the rectilinear volume through the detec-
tions. See Fig. 1 for handgun orientations. tion zone defined by coincident elements of identical grid
3.1.2.1 Discussion—Critical orientations are determined by
testing using a mapping procedure such as described in
Practice C 1270.
3.1.2.2 Discussion—The term 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 out of 10 test
NOTE 1—Numbers are sensitivity setting values for a hypothetical
detector. The numbers represent the lowest sensitivity setting at which the
object was detected ten out of ten consecutive test passes through the
indicated test path.
NOTE 2—Important: ensure that the location of the transmitter and
receiver are identified. If the detector does not have a dedicated transmitter
and receiver, note the side from which testing is performed relative to the
protected area.
FIG. 1 Six Standard Orthogonal Orientations for a Handgun FIG. 2 Example of Detection Sensitivity Map
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 1270
(see Fig. 1 for handgun orientations)
3.1.15 portal, n—see walk-through metal detector.
3.1.16 test element, n—(see Figs. 2 and 3) for the purpose of
testing, it is necessary to define discrete and repeatable
straight-line shortest-course test paths through the detection
zone. This can be done by using two identical networks (grids)
made of nonconductive/nonmagnetic material attached across
the entry and exit planes of the portal aperture so the networks
coincide. A test object on the end of a probe can then be passed
from one side of the portal aperture to the other side through
corresponding openings, which results in the test object taking
a reasonably straight-line shortest-course path through the
detection zone. If the networks are constructed so that they can
be put in-place identically each time they are used, then the test
paths through the detection zone are repeatable over time.
Thus, a test element is the volume of space defined by the
boundaries of two corresponding network openings and it
represents a straight-line shortest-course path through the
detection zone.
3.1.16.1 Discussion—On a detection sensitivity map the
corresponding networks appear as a rectangular grid with each
FIG. 3 3-D View of Detection Zones and Test Grid
element of the grid representing a test path through the
detection zone. The element defining the critical test path is the
works placed on either side of the portal aperture. (see Figs. 2 critical test element.
and 3)
3.1.17 test grid, n—a network of nonconductive/
3.1.11.2 test path, n—as defined by an element on a
nonmagnetic material, such as string or tape, can be stretched
detection sensitivity map, a straight-line shortest-course path
across the entry and exit planes of the portal aperture to define
through the detection zone of a detector undergoing mapping,
test paths through the portal aperture; the material should not
detection sensitivity, or detection sensitivity verification test-
be hygroscopic.
ing. (see Fig. 3)
3.1.17.1 Discussion—See Fig. 2 for an example ofa4by9
3.1.12 element, test element, n—for the purpose of this
element test grid.
testing, a test element is the volume of space defined by the
3.1.18 test object, n—metallic item meeting dimension and
boundaries of two corresponding network openings, and it
material criteria used to evaluate detection performance.
represents a straight-line shortest-course path through the
3.1.18.1 critical test object—the one test object out of any
detection zone.
3.1.12.1 Discussion—It is necessary to define discrete and given group of test objects that in its critical orientation,
produces the weakest detection signal anywhere in the detec-
repeatable straight-line shortest-course test paths through the
detection zone. This can be done by using two identical tion zone.
networks (grids) made of nonconductive/nonmagnetic material
3.1.18.2 Discussion—Depending on the particular detector,
attached across the entry and exit planes of the portal aperture
some orientation sensitive test objects may have different
so the networks coincide. A test object on the end of a probe
locations in the detection zone result in near critical sensitivity
can then be passed from one side of the portal aperture to the
settings. Hence, care must be taken in determining the critical
other side through corresponding openings, which results in the
test object, its critical orientation, and the critical test path.
test object taking a reasonably straight-line shortest-course
3.1.18.3 shielding test object, n—a test object representing
path through the detection zone. If the networks are con-
special nuclear material shielding that might be used in a theft
structed so that they can be put in-place identically each time
scenario.
they are used, then the test paths through the detection zone are
3.1.18.4 Discussion—It is usually a metallic container or
repeatable over time. On a detection sensitivity map the
metallic material configured as a credible gamma-radiation
corresponding networks appear as a rectangular grid with each
shield for a specific type and quantity of special nuclear
element of the grid representing a test path through the
material. The object is specified by a regulatory authority or is
detection zone.
based on the facility threat analysis, or both.
3.1.13 in-plant, adj—installed in the location, position, and
3.1.18.5 weapon test object, n—a handgun(s) or simulated
operating environment where the device will be used.
handgun designated by or satisfying the regulatory authority
3.1.14 orthogonal orientation, n—as used in this practice,
requirement for a test object.
orthogonal orientation refers to alignment of the longitudinal
axis of a test object along the xyz axes of the Cartesian 3.1.18.6 Discussion—Care must be taken when selecting or
coordinate system; x is horizontal and across the portal, y is designing a mock handgun. Simple blocks of metal shaped like
vertical, and z is in the direction of travel through the portal. a handgun will likely not cause a metal detector to react the
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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