1、Designation: C 1238 97 (Reapproved 2003)Standard Guide forInstallation of Walk-Through Metal Detectors1This standard is issued under the fixed designation C 1238; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 Some facilities require that personnel entering desig-nated areas be screened for concealed weapons and othermetallic materia
3、ls. Also, personnel exiting designated areas areoften screened for metallic shielding material and other typesof metallic contraband. Walk-through metal detectors arewidely used to implement these requirements. This guidedescribes various elements to be considered when planning toinstall walk-throug
4、h metal detectors.1.2 This guide is not intended to set performance levels, noris it intended to limit or constrain operational technologies.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard
5、to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 NRC Document:NUREG-1329 Entry/Exit Control At Fuel Fabrication Fa-cilities Using or Possessing Formula Quantities of Strate-gic Special Nuclear Mat
6、erial22.2 U.S. Government Documents:DOE 5632.2A Physical Protection of Special Nuclear Ma-terials and Vital Equipment, February 9, 19883DOE 5633.3 Control and Accountability of Nuclear Mate-rials, February 3, 198832.3 National Fire Protection Associations (NPA) Life SafetyCode Handbook:NFPA-101-1988
7、, Chapter 28, Industrial Occupancy42.4 ANSI Standard:Z41.1-PT-1983 Class 50 and 75For Non-ferrous andFerrous Safety Footwear52.5 National Institute of Law Enforcement and CriminalJustice (NILECJ) Standard:0601.00 For Design, Performance, and Allowable MagneticField Strength33. Terminology3.1 Definit
8、ions of Terms Specific to This Standard:3.1.1 continuous-wave-type metal detectora system gen-erally employing one or more pairs of closely coupled coils.One coil is electrically energized to establish an electromag-netic field; the other detects disturbances in that field. Inoperation, the coils ar
9、e configured so that the person or objectbeing screened passes through the field. When metal passesthrough the field, the field is modified by the magnetic andelectrical properties of the metal. Any change in the field issensed by measuring one or more of many possible parameters,including mutual in
10、ductance, power loss, phase shift, fre-quency shift, permeability, etc.3.1.2 nuisance alarman alarm not caused by a weapon orshielding material but by other causes such as outside interfer-ence or other operationally or environmentally induced stimu-lus. In practice, these alarms are a nuisance beca
11、use they arenot obvious and must be investigated and the cause eliminated.3.1.3 pulse-wave-type metal detectorsa system in whichbrief current pulses are generated in transmitter coils when theyare switched on. The electromagnetic field generated by thesepulses induces eddy currents in metallic objec
12、ts in the field.The eddy currents decay when the transmitter coils are shut off.The decay of the eddy currents produces secondary voltages inthe receiver coils, which are switched on only when thetransmitter coils are switched off. The voltages induced in thereceiver coils are processed and compared
13、 against a bias orbackground level.3.1.4 shieldinga metallic material configured as a crediblegamma-radiation shield for special nuclear materials (SNM).3.1.5 throughputthe actual rate at which a metal detectorand system can screen personnel for a given application.1This guide is under the jurisdict
14、ion of ASTM Committee C26 on Nuclear FuelCycle and is the direct responsibility of Subcommittee C26.12 on SafeguardApplications.Current edition approved Dec. 10, 1997. Published May 1998.2Available from the U.S. Nuclear Regulatory Commission, Washington, DC20555.3Available from U.S. Government Print
15、ing Office, Washington, DC 20402.4National Fire Protection Association, 1 Batterymarch Park, P.O. Box 9101,Quincy, MA 022699101.5Available from American National Standards Institute, 11 W. 42nd St., 13thFloor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West
16、 Conshohocken, PA 19428-2959, United States.3.1.6 walk-through metal detectora free-standing screen-ing device having an electromagnetic field within its portalstructure (aperture) for detecting metallic objects, includingsome nuclear shielding materials, carried by persons walkingthrough the apertu
17、re.3.1.7 weapona device intended to do damage to personnelor equipment without intentionally harming the attacker, butrequiring the attacker to physically activate or use the device.4. Significance and Use4.1 This guide is intended for use by the designers, evalu-ators, and users of walk-through met
18、al detectors to be installedto screen persons entering or leaving a controlled access area.This guide is not meant to constrain design liberty but is to beused as a guide in the selection of location and installation ofwalk-through metal detectors.5. Safety Considerations5.1 Warning signs should be
19、posted if the metal detectorselectromagnetic field strength is of such a magnitude thatpersonal medical devices may be affected or damaged whenthey pass through the portal. See NILECJ Standard 0601.00.5.2 Local fire and safety codes should be reviewed concern-ing requirements for areas selected for
20、metal detector installa-tion. Metal-detector installations needing exemption from thefire and safety requirements should be approved in advance.6. Throughput Consideration6.1 The rate at which persons may be screened is generallyan important factor in security applications. Metal-detectorsystems sho
21、uld be capable of dealing with large transient trafficflow such as found during shift changes.6.1.1 Throughput varies from one metal detector model tothe next. Throughput also varies from one application to thenext. Applications that require high-sensitivity settings willhave lower throughput.6.1.2
22、Once the application specific throughput for a detectormodel has been established, the number of detector lanesrequired to achieve system throughput at peak times can becalculated. See 9.2.7. Other Considerations7.1 Review applicable regulatory orders and policies ofappropriate regulatory agencies a
23、nd facilities for informationpertinent to metal detector installation and operation.7.2 Examine the power capability of the building electricalsystem to ensure that it is adequate to support the metal-detector system, especially current, voltage, and voltage sta-bility.7.3 Confirm that the available
24、 primary and emergencypower are free of noise and transients. If not, install a filteringor regulating system, or both. An uninterruptable power systemcan provide both filtering and emergency power.7.4 Establish where the metal-detector alarms are to betransmitted and who will be responsible for ala
25、rm assessment.7.5 Provide a means for related functions such as space fornearby door opening and closing, door latching, and additionalaudible or visual alarms, or both, as needed to meet all safetyand security requirements.7.6 Where it is necessary to operate metal detectors in closeproximity to ea
26、ch other, they should be of the same manufac-turer and model so that the coils can be synchronized oroperated at different frequencies in accordance with the manu-facturers recommendations. If it is necessary to operate metaldetectors of different models or manufacturers, a test should beconducted f
27、or interference before the detectors are installed.Where metal detectors are not compatible it may be necessaryto isolate the fields of each detector by as much as 20 to 30 ft.7.7 If all electronic equipment is not designed for outdooruse, provide cover and protect the equipment from the ele-ments,
28、especially high temperature and high humidity. Ad-equate ventilation should also be provided. Make sure themetal-detector system is stable over a wide range of environ-mental factors (temperature, humidity, etc.). All metal detectorsare sensitive to changes in the surrounding electromagneticenvironm
29、ent, and that should be the only factor affecting stableoperation.8. Layout of the Installation Site8.1 The site layout for walk-through metal-detector instal-lation should be designed to minimize the guard force person-nel required and to avoid processing delays. The site may be ina new area or bui
30、lding, or in an existing area modified to housesecurity screening devices.8.2 It is good practice to channel people through separateentry and exit lanes. In areas where more extensive outboundscreening is required, separate lanes and equipment are evenmore desirable so that equipment can be optimize
31、d for detec-tion of the specified objects on entry or exit.8.3 If alarms are remotely monitored, the response tactic(guards action, intercept corridors, lockdown schemes, etc.) toalarms must be considered early in the design process to ensureeffective and efficient interdiction.8.4 Installation of e
32、quipment should be arranged to mini-mize nuisance alarms from outside interference. If nuisancealarms are too numerous, the guard force will lose confidencein the equipment, and security may be compromised.8.5 Security equipment often must fit into a space-criticalsite, but adequate space is the sin
33、gle greatest asset for asecurity screening area. Maintaining a well-defined screeningarea is essential so that when an alarm occurs, the securityinspector can clearly identify and isolate the person that causedthe alarm.8.5.1 Layout of the area selected for installation of awalk-through metal detect
34、or should provide adequate space forcalibration and maintenance of the metal detector.8.5.2 Locate equipment in a manner to clear doors, ductwork, piping, and other equipment.8.5.3 The site layout should provide an alternate means toscreen personnel while the metal detector is out of service. SeeApp
35、endix X1.8.5.4 The layout should also provide adequate ventilationfor the electronic equipment.8.6 Since metal-detector portal width is typically less thanthe minimum doorway width required by the Life SafetyCodes, bypass routes that meet the Life Safety Codes require-ments should be included in the
36、 layout design. (See NFPA-101.)C 1238 97 (2003)28.7 Metal detector coil assemblies should be securely an-chored to prevent swaying or tip over. The floor should be solidand not prone to transfer vibration to the metal detector. Areinforced concrete floor is recommended. The concrete shouldbe free of
37、 steel except for grounded reinforcing bars andelectrical conduit which should be grounded. Raised computerroom floors are not solid and should be avoided.8.8 A metal detector will respond to nearby moving metalobjects, but its sensitivity is less for moving material outsidethan inside the detection
38、 zone. To minimize alarms fromoutside moving metal objects, the distance from the metaldetector to the nearest outside metal object should be at least 3ft. The exact minimum distance may vary and must be verifiedexperimentally because response to external moving metal isdependent on the size configu
39、ration and type of metal in theobject.9. Operational Factors9.1 Verify that metal-detector by-pass facilities, nonmetallicpass-around table, and operational procedures are in placebefore starting operation of a metal detector.9.2 During off-hours and between shift changes, facilitydesign of multi-de
40、tector systems should allow some entry andexit lanes to be closed to reduce manpower requirements.9.3 Alarms caused by metallic items that people carry maydecrease as people learn to limit these routine items. Thislearning process can be reinforced by recirculating the peoplethat cause an alarm, hav
41、ing them remove metal items andtrying again rather than hand-searching them. Recirculatingthese individuals will delay their entry and exit and encouragethem to carry less metal on their person. It will also familiarizethem with the objects that cause alarms.9.4 Before starting operation of a site,
42、procedures should bein place that address the response to different types of metalobjects that cause an alarm. Specifically shoes that containmetal toe caps or metal arch supports and medically implantedmetal should be addressed in these procedures. (See ANSIZ41.1PT.)9.5 Screening areas should have
43、guard force personnelphysically located in the area where people are to be screenedso they can observe and respond. Guard force personnel shouldhave good visual and audible interaction with both the equip-ment and the personnel.10. Interferences to Metal Detector Operations10.1 If two or more metal
44、detectors are operating in closeproximity, they should be synchronized or operated at separatefrequencies according to the manufacturers recommendations.See 7.6.10.2 Very large metal objects such as metal plates or sheets,within 3 ft of the metal detector coil can reduce its detectionsensitivity. If
45、 a large metal object is relocated near a metaldetector, then recalibration and sensitivity testing is required.See Appendix X1.10.3 A significant problem can be caused if the metal-detector assembly moves and causes alarms. To eliminate thispossible cause of nuisance alarms, anchor the detector ass
46、em-bly firmly to the floor.10.4 For high-sensitivity operations, extra caution must betaken to avoid the adverse influence of external moving metalsurfaces. Examples of the moving metal objects are doors,conveyors, fans, elevators, walls, vehicles, and metal carts.10.5 Electrical interference to met
47、al detectors, both radiatedand conductive, may be caused by electric motors, relaycontact opening and closing, nearby high-voltage equipment,radio transmitters, computer cables, public-address systemsand speakers, tube-type CCTV cameras and monitors, fluores-cent lights, electric welders, and simila
48、r electrical equipment.10.5.1 Electric interferences can be decreased by increasingthe distance between a metal detector and the interferingsource, rotating the position of the metal detector in relation tothe interference, or by suppressing or shielding the source ofthe interference and the metal d
49、etector, or both.11. Selecting and Installing Equipment11.1 When selecting and installing walk-through metaldetectors, the physical and electrical compatibility of the metaldetector with other equipment that may be installed nearby,such as X-ray equipment, explosive detectors, and specialnuclear materials detectors must be considered. See AppendixX2.11.2 The metal-detector portal structure should provide, atminimum, a vertical head clearance of 612 ft (1950 mm) and ahorizontal width of 28 in. (700 mm). See 8.6.11.3 The walk-through metal-detector portal should be con-struc
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