1、Designation: C1270 97 (Reapproved 2012)Standard Practice forDetection Sensitivity Mapping of In-Plant Walk-ThroughMetal Detectors1This standard is issued under the fixed designation C1270; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONNuclear regulatory authorities require personnel entering designated security areas to be screenedfo
3、r concealed weapons. Additionally, in security areas containing specified quantities of specialnuclear 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 environment
4、al conditions, architectural and electrical arrangements near the detector,and detector characteristics affect the detection of metallic objects passing through the walk-throughmetal detector. These external effects and detector characteristics are discussed in Practices F1468 andC1269, and Guide C1
5、238. This practice is intended to minimize the effects of these variables ondetector operation by providing the operator with baseline information on the metal detectionsensitivity within the portal aperture, particularly the location of any weak areas of detection. The datais obtained by mapping th
6、e detection zone (volume within the portal) of each detector at its fieldlocation, under normal operating conditions, and using the target test object. The maps, when appliedto detector operation, ensure that the effects of the fixed environmental conditions, architectural andelectrical arrangements
7、, and detector characteristics are taken into account during operationalsensitivity adjustment, performance evaluation, and general operation of detectors.1. Scope1.1 This standard practice covers a procedure for determin-ing the weakest detection path through the portal aperture andthe worst-case o
8、rthogonal orientation of metallic test objects. Itresults in detection sensitivity maps, which model the detectionzone in terms related to detection sensitivity and identify theweakest detection paths. Detection sensitivity maps supportsensitivity adjustment and performance evaluation procedures(see
9、 Practices C1269 and C1309).NOTE 1Unsymmetrical metal objects possessing a primary longitudi-nal component, such as handguns and knives, usually have one particularorientation that produces the weakest detection signal. The orientation andthe path through the detector aperture where the weakest resp
10、onse isproduced may not be the same for all test objects, even those with verysimilar appearance.NOTE 2In the case of multiple specified test objects or for test objectsthat are orientation sensitive, it may be necessary to map each objectseveral times to determine the worst-case test object or orie
11、ntation, orboth.1.2 This practice is one of several developed to assistoperators of walk-through metal detectors with meeting themetal detection performance requirements of the responsibleregulatory authority. (See Appendix X2)1.3 This practice is neither intended to set performancelevels, nor limit
12、 or constrain operational technologies.1.4 This practice does not address safety or operationalissues associated with the use of walk-through metal detectors.1.5 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.2. Referenced Doc
13、uments2.1 ASTM Standards:2C1238 Guide for Installation of Walk-Through Metal De-tectorsC1269 Practice for Adjusting the Operational SensitivitySetting of In-Plant Walk-Through Metal DetectorsC1309 Practice for Performance Evaluation of In-PlantWalk-Through Metal Detectors1This practice is under the
14、jurisdiction of ASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.12 on SafeguardApplications.Current edition approved Jan. 1, 2012. Published January 2012. Originallyapproved in 1994. Last previous edition approved in 1997 as C1270 97(2003).DOI: 10.1520/C1
15、270-97R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Driv
16、e, PO Box C700, West Conshohocken, PA 19428-2959, United States.F1468 Practice for Evaluation of Metallic Weapons Detec-tors for Controlled Access Search and Screening3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 clean-tester, na person who does not carry anyextraneous metal
17、lic objects that would significantly alter thesignal produced when the person carries a test object.3.1.1.1 DiscussionBy example but not limitation, suchextraneous metallic objects may include: metallic belt buckles,metal buttons, cardiac pacemakers, coins, metal frame eyeglasses, hearing aids, jewe
18、lry, keys, mechanical pens andpencils, shoes with metal shanks or arch supports, metallicsurgical implants, undergarment support metal, metal zippers,etc. In the absence of other criteria, a clean tester passingthrough a metal detector shall not cause a disturbance signalgreater than 10 % of that pr
19、oduced when carrying the criticaltest object through the detector. Test objects requiring veryhigh sensitivity settings for detection require more completeelimination of extraneous metal to obtain less than 10 % signaldisturbance.3.1.1.2 DiscussionThe tester shall have a weight between50 to 104 kg (
20、110 to 230 lb) and a height between 1.44 to 1.93m (57 to 75 in.). Should a given detector be sensitive to bodysize because of design or desired sensitivity, the physical sizeof testers should be smaller and within a narrower range.3.1.1.3 DiscussionIt is recommended that the clean testerbe surveyed
21、with a high sensitivity hand-held metal detector toensure that no metal is present.3.1.2 critical orientation, nthe orthogonal orientation of atest object that produces the smallest detection signal orweakest detection anywhere in the detection zone; the orthogo-nal orientation of a test object that
22、 requires a higher sensitivitysetting to be detected compared to the sensitivity settingrequired to detect the object in all other orthogonal orienta-tions. See Fig. 1 for handgun orientations.3.1.2.1 DiscussionCritical orientations are determined bytesting using a mapping procedure such as describe
23、d inPractice C1270.3.1.2.2 DiscussionThe term critical orientation can referto the worst case orthogonal orientation in a single test path orthe worst case orthogonal orientation for all the test paths (theentire detection zone). The two are coincident in the critical testpath.3.1.3 critical sensiti
24、vity setting, nthe lowest sensitivitysetting of a detector at which the critical test object in itscritical orientation is consistently detected (10 out of 10 testpasses) when passed through the detection zone on the criticaltest path.3.1.4 critical test element, nsee test element.3.1.5 critical tes
25、t object, nsee test object.3.1.6 critical test path, nthe straight-line shortest-coursepath through the portal aperture, as defined by an element onthe detection sensitivity map, that produces the smallestdetection signal or weakest detection for a test object in itscritical orientation. (see Figs.
26、2 and 3)3.1.7 detection sensitivity map, n(see Figs. 2 and 1)adepiction of the grid used to define test paths through thedetection zone, with each element of the grid containing avalue, usually the sensitivity setting of the detector, that isindicative of the detectability of the test object.3.1.7.1
27、 DiscussionThese values are relative and describethe detection sensitivity pattern within the detection zone forthe specific test object. The values are derived by identicallytesting each defined test path using a specific test object in asingle orthogonal orientation. The value is usually the mini-
28、mum sensitivity setting of the detector that will cause aconsistent alarm (10 out of 10 test passes) when the test objectis passed through the detection field. Appendix X3 is a sampleform for a potential detection sensitivity map configuration.FIG. 1 Six Standard Orthogonal Orientations for a Handgu
29、nNOTE 1Numbers are sensitivity setting values for a hypotheticaldetector. The numbers represent the lowest sensitivity setting at which theobject was detected ten out of ten consecutive test passes through theindicated test path.NOTE 2Important: ensure that the location of the transmitter andreceive
30、r are identified. If the detector does not have a dedicated transmitterand receiver, note the side from which testing is performed relative to theprotected area.FIG. 2 Example of Detection Sensitivity MapC1270 97 (2012)23.1.8 detection zone, nthe volume within the portal aper-ture.3.1.9 detector, ns
31、ee walk-through metal detector.3.1.10 element, nsee test element3.1.11 grid, nsee test grid3.1.11.1 grid element, n(1) a single block on a detectionsensitivity map; (2) the rectilinear volume through the detec-tion zone defined by coincident elements of identical gridworks placed on either side of t
32、he portal aperture. (see Figs. 2and 3)3.1.11.2 test path, nas defined by an element on adetection sensitivity map, a straight-line shortest-course paththrough the detection zone of a detector undergoing mapping,detection sensitivity, or detection sensitivity verification test-ing. (see Fig. 3)3.1.12
33、 element, test element, nfor the purpose of thistesting, a test element is the volume of space defined by theboundaries of two corresponding network openings, and itrepresents a straight-line shortest-course path through thedetection zone.3.1.12.1 DiscussionIt is necessary to define discrete andrepe
34、atable straight-line shortest-course test paths through thedetection zone. This can be done by using two identicalnetworks (grids) made of nonconductive/nonmagnetic materialattached across the entry and exit planes of the portal apertureso the networks coincide. A test object on the end of a probeca
35、n then be passed from one side of the portal aperture to theother side through corresponding openings, which results in thetest object taking a reasonably straight-line shortest-coursepath through the detection zone. If the networks are con-structed so that they can be put in-place identically each
36、timethey are used, then the test paths through the detection zone arerepeatable over time. On a detection sensitivity map thecorresponding networks appear as a rectangular grid with eachelement of the grid representing a test path through thedetection zone.3.1.13 in-plant, adjinstalled in the locati
37、on, position, andoperating environment where the device will be used.3.1.14 orthogonal orientation, nas used in this practice,orthogonal orientation refers to alignment of the longitudinalaxis of a test object along the xyz axes of the Cartesiancoordinate system; x is horizontal and across the porta
38、l, y isvertical, and z is in the direction of travel through the portal.(see Fig. 1 for handgun orientations)3.1.15 portal, nsee walk-through metal detector.3.1.16 test element, n(see Figs. 2 and 3) for the purpose oftesting, it is necessary to define discrete and repeatablestraight-line shortest-co
39、urse test paths through the detectionzone. This can be done by using two identical networks (grids)made of nonconductive/nonmagnetic material attached acrossthe entry and exit planes of the portal aperture so the networkscoincide.Atest object on the end of a probe can then be passedfrom one side of
40、the portal aperture to the other side throughcorresponding openings, which results in the test object takinga reasonably straight-line shortest-course path through thedetection zone. If the networks are constructed so that they canbe put in-place identically each time they are used, then the testpat
41、hs through the detection zone are repeatable over time.Thus, a test element is the volume of space defined by theboundaries of two corresponding network openings and itrepresents a straight-line shortest-course path through thedetection zone.3.1.16.1 DiscussionOn a detection sensitivity map thecorre
42、sponding networks appear as a rectangular grid with eachelement of the grid representing a test path through thedetection zone. The element defining the critical test path is thecritical test element.3.1.17 test grid, na network of nonconductive/nonmagnetic material, such as string or tape, can be s
43、tretchedacross the entry and exit planes of the portal aperture to definetest paths through the portal aperture; the material should notbe hygroscopic.3.1.17.1 DiscussionSee Fig. 2 for an example ofa4by9element test grid.3.1.18 test object, nmetallic item meeting dimension andmaterial criteria used
44、to evaluate detection performance.3.1.18.1 critical test objectthe one test object out of anygiven group of test objects that in its critical orientation,produces the weakest detection signal anywhere in the detec-tion zone.3.1.18.2 DiscussionDepending on the particular detector,some orientation sen
45、sitive test objects may have differentlocations in the detection zone result in near critical sensitivitysettings. Hence, care must be taken in determining the criticaltest object, its critical orientation, and the critical test path.3.1.18.3 shielding test object, na test object representingspecial
46、 nuclear material shielding that might be used in a theftscenario.3.1.18.4 DiscussionIt is usually a metallic container ormetallic material configured as a credible gamma-radiationshield for a specific type and quantity of special nuclearFIG. 3 3-D View of Detection Zones and Test GridC1270 97 (2012
47、)3material. The object is specified by a regulatory authority or isbased on the facility threat analysis, or both.3.1.18.5 weapon test object, na handgun(s) or simulatedhandgun designated by or satisfying the regulatory authorityrequirement for a test object.3.1.18.6 DiscussionCare must be taken whe
48、n selecting ordesigning a mock handgun. Simple blocks of metal shaped likea handgun will likely not cause a metal detector to react thesame as it would to the intricate shapes and variable compo-nents of a real handgun. Most government agencies use actualguns for testing.3.1.19 walk-through metal de
49、tector (detector, portal), nafree-standing screening device, usually an arch-type portal,using an electromagnetic field within its portal structure(aperture) for detecting metallic objects, specifically weaponsor metallic shielding material, or both, on persons walkingthrough the portal.3.1.20 walk speed (Normal), nwalk speed is between 0.5to 1.3 m/s (112 to 212 steps/s).3.1.20.1 DiscussionThe average casual walk rate is about134 step/s.3.1.20.2 shielding test object, nsee test object.3.1.20.3 weapon test object, nsee test object.4. S
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