ASTM C1269-97

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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Designation: C 1269 – 97
Standard Practice for
Adjusting the Operational Sensitivity Setting of In-Plant
Walk-Through Metal Detectors
This standard is issued under the fixed designation C 1269; 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, personnel exiting the facility are required to be screened for metallic nuclear
shielding material. Walk-through metal detectors are widely used to implement these requirements.
Nuclear regulatory authorities usually specify an assortment of metal detector test objects that must
all be detected by walk-through metal detectors. This practice provides a procedure for adjusting the
operational sensitivity setting to the lowest setting necessary to detect the least likely to-be-detected
test object in its least likely to-be-detected orientation while passing through the detection zone in the
weakest known detection path. All other test objects will then be detected at this sensitivity setting
anywhere in the detection zone.
1. Scope standards. The values given in parentheses are for information
only.
1.1 This practice covers a procedure for adjusting the
operational sensitivity of in-plant walk-through metal detec-
2. Referenced Documents
tors. Performance of this procedure should result with in-plant
2.1 ASTM Standards:
walk-through metal detectors being adjusted to an initial
C 1238 Guide for Installation of Walk-Through Metal De-
operational sensitivity setting suitable for performance testing.
tectors
1.2 This practice does not set test object specifications or
C 1270 Practice for Detection Sensitivity Mapping of In-
specify specific test objects. These should be specified by the
Plant Walk-Through Metal Detectors
regulatory authority.
C 1309 Practice for Performance Evaluation of In-Plant
1.3 This practice uses information developed by Practice
Walk-Through Metal Detectors
C 1270, or an equivalent procedure, which identifies the
F 1468 Practice for the Evaluation of Metallic Weapons
critical test object (from a specified set of test objects), its
Detectors for Controlled Access Search and Screening
critical orientation, and the critical test path through the
detection zone. In the case of Practice C 1270, the information
3. Terminology
is found on the detection sensitivity map(s) for each in-plant
3.1 Definitions of Terms Specific to This Standard:
walk-through metal detector.
3.1.1 clean-tester, n—a person who does not carry any
1.4 This practice is one of several developed to assist
extraneous metallic objects that would significantly alter the
operators of nuclear facilities with meeting the metal detection
signal produced when the person carries a test object.
performance requirements of the regulatory authorities (see
3.1.1.1 Discussion—Smaller test objects require more com-
Appendix).
plete elimination of metallic objects. By example but not
1.5 This standard practice is neither intended to set perfor-
limitation, such extraneous metallic objects may include:
mance levels nor limit or constrain technologies.
metallic belt buckles, metal buttons, cardiac pacemakers, coins,
1.6 This practice does not address safety or operational
metal frame eyeglasses, hearing aids, jewelry, keys, mechani-
issues associated with the use of walk-through metal detectors.
cal pens and pencils, shoes with metal shanks or arch supports,
1.7 The values stated in SI units are to be regarded as
metallic surgical implants, undergarment support metal, metal
zippers, etc. In the absence of other criteria, a clean tester
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.
Current edition approved Dec. 10, 1997. Published June 1998. Originally Annual Book of ASTM Standards, Vol 12.01.
published as C 1269 – 00. Last previous edition C 1269 – 94. 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 1269
passing through a metal detector shall not cause a disturbance
signal greater than 10 % of that produced when carrying the
critical test object through the detector. Test objects requiring
more complete elimination of extraneous metal to obtain less
than 10 % signal disturbance.
3.1.1.2 Discussion—The tester shall have a weight between
50 to 104 kg (110 to 230 lb) and a height between 1.44 to 1.93
m (57 to 75 in.). Should a given detector be sensitive to body
size because of design or desired sensitivity, the physical size
of testers should be smaller and within a narrower range.
3.1.1.3 Discussion—It is recommended that the clean tester
be surveyed with a high sensitivity hand-held metal detector to
ensure that no metal is present.
3.1.2 critical orientation—the orthogonal orientation of a
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. 1 for handgun orientations
NOTE 1—Numbers are sensitivity setting values for a hypothetical
3.1.2.1 Discussion—Critical orientations are determined by
detector. The numbers represent the lowest sensitivity setting at which the
testing using a mapping procedure such as described in
object was detected ten out of ten consecutive test passes through the
Practice C 1270. indicated test path.
FIG. 2 Example of Detection Sensitivity Map
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 out of 10 test
passes) when passed through the detection zone on the critical
test path.
3.1.4 critical test element, n—see test element.
3.1.5 critical test object, n—see test object.
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 the critical test object
in its critical orientation. (see Figs. 2 and 3)
3.1.7 detection sensitivity map, n—(see Fig. 2) a depiction
of the grid used to define test paths through the detection zone
FIG. 3 3-D View of Detection Zones and Test Grid
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.
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
FIG. 1 Six Standard Orthogonal Orientations for a Handgun consistent alarm (10 out of 10 test passes) when the test object
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 1269
is passed through the detection field. Appendix X2 is a sample produces the weakest detection signal anywhere in the detec-
form for a potential detection sensitivity map configuration. tion zone. The group referred to consists of one or more objects
that are to be detected at the same detector setting.
3.1.8 detection zone—the volume within the portal aperture.
3.1.18.2 Discussion—Depending on the particular detector,
3.1.9 detector, n—see walk-through metal detector.
some orientation sensitive test objects may have orientations at
3.1.10 element, n—see test element.
different locations in the detection zone that result in near
3.1.11 grid, n—see test grid.
critical sensitivity settings. Hence, care must be taken in
3.1.12 grid element, n—(1) a single block on a detection
determining the critical test object, its critical orientation, and
sensitivity map; (2) the rectilinear volume through the detec-
the critical test path.
tion zone defined by coincident elements of identical grid
3.1.18.3 shielding test object—a test object representing
works placed on either side of the portal aperture. (see Figs. 2
special nuclear material shielding that might be used in a theft
and 3)
scenario.
3.1.12.1 test path, n—as defined by an element on a
3.1.18.4 Discussion—It is usually a metallic container or
detection sensitivity map, a straight-line shortest-course path
metallic material configured as a credible gamma-radiation
through the detection zone of a detector undergoing mapping,
shield for a specific type and quantity of special nuclear
detection sensitivity, or detection sensitivity verification test-
material. The object is specified by a regulatory authority or is
ing. (see Fig. 3)
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—as used in this practice,
requirement for a weapon test object.
orthogonal orientation refers to alignment of the longitudinal
3.1.18.6 Discussion—Care must be taken when selecting or
axis of a test object along the xyz axes of the Cartesian
designing a mock handgun. Simple blocks of metal shaped like
coordinate system; x is horizontal and across the portal, y is
a handgun will likely not cause a metal detector to react the
vertical, and z is in the direction of travel through the portal.
same as it would to the intricate shapes and variable compo-
3.1.15 portal, n—see walk-through metal detector. (See
nents of a real handgun. Most government agencies use actual
Fig. 1 for handgun orientations)
guns for testing.
3.1.16 test element, n—(see Figs. 2 and 3) for the purpose of
3.1.19 walk-through metal detector (detector, portal), n—a
testing, it is necessary to define discrete and repeatable
free-standing screening device, usually an arch-type portal,
straight-line shortest-course test paths through the detection
using an electromagnetic field within its portal structure
zone. This can be done by using two identical networks (grids)
(aperture) for detecting metallic objects, specifically weapons
made of nonconductive/nonmagnetic material attached across
or metallic shielding material, or both, on persons walking
the entry and exit planes of the portal aperture so the networks
through the portal.
coincide. A test object on the end of a probe can then be passed
3.1.20 walk speed (normal), n—walk speed is between 0.5
from one side of the portal aperture to the other side through
1 1
to 1.3 m/s (1 ⁄2to 2 ⁄2steps/s).
corresponding openings, which results in the test object taking
3.1.20.1 Discussion—The average casual walk rate is about
a reasonably straight-line shortest-course path through the
1 ⁄4 steps/s.
detection zone. If the networks are constructed so that they can
3.1.20.2 shielding test object, n—see test object.
be put in-place identically each time they are used, then the test
3.1.20.3 weapon test object, n—see test object.
paths through the detection zone are repeatable over time.
Thus, a test element is the volume of space defined by the
4. Summary of Practice
boundaries of two corresponding network openings and it
4.1 A clean-tester carries the critical test object in the
represents a straight-line shortest-course path through the
critical orientation through the critical test element in the
detection zone.
normal operating fashion. The metal detector sensitivity is
3.1.16.1 Discussion—On a detection sensitivity map the
adjusted upward, starting from a setting where no alarms occur,
corresponding networks appear as a rectangular grid with each
until the lowest sensitivity setting is found where 10 consecu-
element of the grid representing a test path through the
tive passes result with 10 consecutive alarms. This value is the
detection zone. The element defining the critical test path is the
initial operational sensitivity setting.
critical test element.
5. Significance and Use
3.1.17 test grid, n—a network of nonconductive/
nonmagnetic material, such as string or tape, can be stretched
5.1 Performing this procedure from this practice should
across the entry and exit planes of the portal aperture to define
result in a properly adjusted walk-through metal detector
test paths through the portal aperture; the material should not
operating at or near the optimum sensitivity setting for the
be hygroscopic.
environment in which it is installed.
3.1.17.1 Discussion—See Fig. 2 for an example ofa4by9
5.2 This practice determines the lowest sensitivity setting
element test grid.
required to detect a specified test object and establishes a
3.1.18 test object, n—metallic item meeting dimension and sensitivity setting suitable for most operational needs.
material criteria used to evaluate detection performance.
5.3 This practice may be used to establish an initial sensi-
3.1.18.1 critical test object—the one test object out of any tivity setting for follow-on procedures that determine credible
given group of test objects that, in its critical orientation, values for probability of detection and confidence level, as
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 1269
required by regulatory authorities. test object is determined by in-plant sensitivity ma
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