Regulatory Guide 5.44

Perimeter Intrusion Alarm Systems

ML13350A239
Person / Time
Issue date:	01/31/1975
Revision:	0
From:	US Atomic Energy Commission (AEC)
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RG-5.044
Download: ML13350A239 (6)

I.January 1975U.S. ATOMIC ENERGY COMMISSIONREGULATORYDIRECTORATE OF REGULATORY STANDARDSREGULATORY GUIDE 5.44PERIMETER INTRUSION ALARM SYSTEMSGUIDEA. INTRODUCTIONParagraph (bX4) of §73.50 of the Commiision'sregulations requires that, at fuel reprocessing plants andcertain other plants at which highly enriched uranium,uranium-233, or plutonium is used or processed, theisolation zone surrounding the physical barrier at theperimeter of the protected area be monitored to detedtthe presence of individuals or vehicles within the zone soas to allow response by armed members of the licenseesecurity organization to be initiated at the time ofpenetration of the protected area. guide describesfive types of perimeter intrusion alarm systems and setsforth criteria for their performance and use as a meansacceptable to the Regulatory staff of meeting the abnverequirement.1. DISCUSSIONPerimeter intrusion alarm systems can be used todetect intrusion into or through the isolation zone at theperimeter of the protected area.. A system generallyconsists of one or more sensors, electronic processingequipment, a power supply, and an alarm monitor.Detection of an intruder is accomplished by the alarmsystem responding to some change in its operatingcondition caused by the intruder, e.g., interruption of atransmitted infrared or microwave beam or stress ex-erted on a piezoelectric crystal. The choice of aperimeter alarm system is influenced by considerationsof terrain and climate. At present. no single perimeterintrusion alarm system is capable of operating effectivelyin all varieties of environments.The mode of installation of the perimeter alarmsystem influences the effectiveness of the perimeterintrusion alarm. In general, dividing the Aite perimeterinto segments that are independently alarmed anduniquely monitored .ssists the security organization inresponse to an alarm by localizing the area in which thealarm initiated. Segmenting tof the petimetet alarmsystem also allows testing and maintenance ot a portionof the system while maintaining the rernainder Gf theperimeter under monitoring. It is gVracatly desirable thatthe individual segments be limfited to a length whichallows obsci iation of the zntixe segment by an individualstanding at one end of the segment..Effective use of a periwetel intrusion alarm systemis facilitated by a regular program of system testing.Testing for operability can be performed by a guard orwatchman penetrating the zone protected by the alarmsystem during routine patrols. Functional performancetesting, however, is usually more elaborate. In an), case,testing can. be meaningful without comptomisingsecurity only if performed under controlled stances such as direct visual observation of the area beingtested while a specified test is conducted.The following discus~ion describes the operations,limitations, and envirornental considetations of fivebasie types of commercially available perimeter intrusionalarm systems-microwave, ferrous metal detector,pressure-sensitive, infrared, and vibration- or stress-sensitive fence protection systems.1. Microwave Peimeter Alarm SystemEach link of a microwave perimeter alarm system iscomposed of a transmitter, receiver, and power supply.The microwave transmitter produces a beam-like patternof microwave energy directed to the receiver, whichsenses the microwave beam. A partial or total inter-ruption of the beam will cause an alarm cmidition. Themicrowave beam can be modulated to reduce inter-ference from spurious sources of radiofrequency energy,to increase sensitivity, and to decrease the vulnerabilityto defeat from "capture" of the receiver by a falsemicrowave source.USAEC REGULATORY GUIDE$ Copm at of pmstwsh Oukla fWV be cebtaived by request Iindlest, the C"isso#sdaenwd to Itte US. Asomfra ~wgy Comnmaihson. Wn~mpaý, D.C. 2054S.Regulatory Guides sre isue~d to desaib. ansd rnsk. rev bto to the pubic Attat-ion: Dsr~Vr 01 RagwIatu' Smt"Lb.ft COW"t' en a MOi t ftZA fortrWthasodt aroapia to tho AE C Raouiatorv is"a of implfl9*~tir specific o"aofl 4 il?~ imrerrntt thw pal WS'qded IaMb at t f.Srewlisa Conttustijon's reguletiont. to detInsstetachslqvue .*J by Ith. staff in of 016 Caflnt,,Ilsak. U.S. Asl EWT COrnmbeictt. WahWtO"s O.C. 7.0&0,avekselinfp specifi probterms ot poetubtatd acidesnn, oro crowd@ grklsrsor to Attentions: 0occtatisg nd Se"weasuctoss.aW~inmttt Regulatory Guides ane not ssebatlutae for regulaions and -otfecwithts ites nestt reAqured. Meathods aOW solutiom diltarat fromi Oae an WIout ins The psidn a isue A% ItM fOOWIvW* W breed dWovtssthe pulde, swill be ,cpal S It they V Ovid$ a bests fer the fIndings requisit tol~isa sasaoror aoititsssaseaof apermit as ilcaee bytheCo 1*~f1. Fosrm ftaca &. pfodwmt2. Aeemrth and Teest ftactn .TtoatsmpStioA3. Fusht an~d Measarlta Facititles IL Oca0 at0s0aIe mob"%Published gu=a witl be sashed perodcall. ae sspprowiate. to smormrnvodats, 4. fEsrossmassts *me Sltwqs 9. Asstttlus: Na.1ecomsnftretsmd reflect few Iseforrsiutln or essasianca. 5. uritermia Ord P"&n% Protection 10. OatOrat 71. I..,,,at least 3 meters from parallel running metal fences andat least 20 meters from public roads to minimizenuisance alarms.d. Presume-Sensitive Pesimeter Alarm Systems(1) Performance Criteria. A pies-ure-sensitiveperimeter alarm system should be capable of detectingan individual weighing no more than 35 kilogramscrossing the sensitive area of the system at a ninimunimspeed of 0.3 meter per second whether walking, crawl.ing, or rolling. The system design should employtechniques (etg.. electronic signpi processing) to elimi-nate nuisance alarms from wind noise.(2) Criteria. The sensors should beinstalled at the depth below the ground wurfa~e stated bythe manufacturer. To obtain a high probability ofdetection, the sensors should be in two separate parallellines at a distance from 1.5 to 2 meters apart. Thesensors and electronic circuitry buried in the groundshould be of a durable, moisturepfouf, rt(Aent-resistantmaterial. When a pressure-sensitive perimeter alarmsystem is being installed in rocky soil, all rocks should beremoved during backfilling to prevent damage to sensors.If the frost line exceeds 10 cm, a buriedpressure-sensitive system should nit be used unless thesoil is specifically prepared to eliminate freezing abovethe sensor.e. Infrared Perimeter Alarm Systems(1) Performance Criteria. An infrared pen-meter alarm system should be a nhultibeam modulatedtype consisting of a minimum of three transmitters andthree receivers per unit. An alarm condition should begenerated when 90% of the beams are blocked for aperiod of 75 milliseconds or more or when any onebeam is blocked for a period of 1.25 seconds or more.Furthermore. the system should be able to operate asabovemwith a factor of 20 (13 dB) insertion loss due toatmospheric attenuation (e.g., fog) at maximum range(100 meters).(2) nstallation Criteria. An infrared perimeteralarm system should be installed so that, at any point,the lowest beam Is no higher than 21 cm above grade.The distance between transmitters and receivers of a unitshould not exceed 100 meters.The transmitters and receivers should bemounted rigidly (e.g., installed on a rigid post orconcrete pad) to prevent nuisance alarms from vibra-tions. Installation should provide "overlap" of adjacentunits. The maximum distance between transmitter andreceiver should be selected to permit proper operationduring conditions of severe atmospheric attenuation thatare typical for the site, generally a maximum of 100meters.The infrared perimeter alarm systemshould be installed outside of and parallel to a fence orwall so that the transmitter and receiver units arepositioned between 0.3 and 1.0 meter from the fence orwall. If the infrared alarm sys4em is installed inside andparallel to a fence, the transmitter and receiver unitsshould be positioned between 2.0 and 2.5 meters fromthe fence to prevent an individual from jumpthng overthe infrared beams fronm atop the fence or sprintingthrmugh the beams. Installation of the infrared alarmsystem inside and adjacent to a wall should be avoidedsince the wall provides a sti,0 ba.c Iron which anintruder can jump over the into the protectedaICO.f. Vibration or Strain Dketection(1) Performance Criteria. Vibration- or strain.detection systems uted for fence protction shoulddetect an intruder weighiig no more than 3S kilograinsattempting to climb the fence. The system should alsodetect any att empt to cut the fence Mr lift the lfencemore than 15 cut above grade. The system should notgenerate alarms due to wind-produced vibration of thefence.(2) Installation Criteria. The vibration or strainsensors should be attached firmly to the fence (post orfabric. as appropriate) so that the vibration or stresscaused by an intruder climbing, cutting, or lifting thefence will generate an alarm.2. Testing Perimeter Intrusion Alarm Systemsa. Routine TestingPerimeter intrusion alarm systems sh-iuld betested at least unce each seven days. Testing may beaccomplished during routine patrols by the members ofthe licensee security force, The alarm systems should betested in segments at random with only one or twosegments tested per patrol. However, every segmentshould be tested at least once every seven days. Thetesting should be wonducted by crossing the isolationYone where the alarm system is located or by clinbingthe fence to which the system is attached. Whereappropriate, a specific test procedure should be fol-lowed. Prior to making the test, the individual makingthe test should notify the central alarm station that atest is about to be conducted. The area under test shouldbe maintained under visual observation by a guard.b. Performance TestingAt least quarterly, the perimeter Intrusionalarm system should be, tested against Its functionalperformance specifications. The test procedure recom-mended by the manufacturer should be followed. Whilethe test is being conducted, the area under test should bemaintained under direct visual observation by a guard.5.44-5 Successive microwave links can be overlapped toform a protective perimeter around a facility. However,as. the transmitter/receiver link is a line-of-sight.system,hills or other obstructions will interrupt the beam, andditches may provide crawl space for an intruder.Moreover, objects such as tumbieweeds, paper, andbushes moving in the path of the beam can causenuisance alarms. Systems utilizing the Doppler shift formotion detection are especially sensitive to the motionof trees and grass and to falling rain and snow.The maximum and minimum separation of thetransmitter and receiver usually is specified by themanufacturer. Typically, a microwave perimeter alarmsystem will operate effectively in the range between 70and 150 meters.2. Ferrous Metal Detector Perimeter Alarm SystemA ferrous metal detector system cornsists of buriedelectrical cables, amplifiers, inhibitors, and a centralalarm unit. The system is passive and is susceptible tochanges in the ambient magnetic field. Such changes arecaused either by electromagnetic disturbances such aslightning or by ferrous metal being carried over theburied cables. The change in the local magnetic fieldinduces a current in the buried cable whiLch is filteredand sensed by the electronics, If the change exceeds apredetermined threshold, an alarm is generated. Toreduce nuisance alarms from external electromagneticsources (e.g., electrical power transmission lines), theelectrical cable is laid in loops which are transposed atregular Intervals. The inhibitor, which operates on thesame principle as the cable loops and is buried near acable loop, senses strong temporary electromagneticinterference (e.g., lightning) and disables the alarmsystem for approxir,,mtely one second, thus reducingnuisance alarms.The ferrous metal detector system is not a line-of-sight system and therefore can be installed on unevenground and need not be laid in a straight line. The loopsformed by the cables must be fairly regular, however. Asthe system will detect only ferrous metal, animals, birds,or flying leaves will not initiate alarms. However,electromagnetic interferences can cause nuisance alarmsor even disable the alarm system if the interference issevere.Each sensing cable (and amplifier) can monitor aline up to 500 meters in length. Multiple cables andamplifiers can be used to extend the monitoring length.3. Pressure-Sensitive Perimeter Alarm SystemBuried pressure transducers detect small variationsIn the mechanical stress exerted on the surrounding soilby the presence of an individual passing above thesensor. The signals produced by the transducers areamplified and compared with a preestablished threshold.If the signal exceeds the threshold, an alarm occurs. Thetransducer may be a set of piezoelectric crystals, afluid-filled flexible tube, or a specially fabricated elec-trical cable..Like the ferro!us metal detector system. thepressure-sensitive system does not require line-of.sightinstallation and can be sited on uneven terrain. However.installation in rocky soil may result in daniage to thepressure transducers either during installation or as aresuft of soil settlement afte: installation. High windscan produce pressure waves on the ground surface whichcan be sensed by the transducer and could nectssitateoperation at reduced sesnsitivity to avowd nuisancealarms; however, features to cumpensate for winid-generated noise can be de.iigned into the equipment.Prissure systems also may lose sensitivity if the buriedsensors axe covered with snow, by snow with a frozencrust that will support the weight cf a man, or by frozenground. Other natural phenomena such as hail and raincan cause nuisance alarms.The sensitive area consists of a rtarrow corridor,usually about one meter in width. A greater degree ofsecurity can be azhieved by employing two suchcorridors to prevent an intruder jumping over the buriedtransducers. Typical maximum length monitored by atransducer (i.e., a set of piezoelectric crystals, a liquid-filled tube, or an electrical cable) is about 100 meteis.4. Infrared Perimeter Alarm SystemsUke the microwave system, each link of an infraredsystem is composed of a transmitter, receiver, powersupply, and alarm annunciator. The transmitter directs anarrow beam to a receiver. " -he infrared beam betweenthe transmitter and receiver is interrupted, an alarmsignal is generated. As with the microwave system, theinfrared system is line of sight. In addition, the infraredbe'm is usually modulated. Since the infrared beam doesnot diverge significasitly as does the microwave beam,multiple infrared beams between transmitter and re-ceiver can be used to define a "wall". If this "'wall" isthen penetrated by an individual, an alarm will result.Fog both attentuates and disperses the infraredbeam and can cause nuisance alarms. However, thesystem can be designed to operate properly with severeatmospheric attenuation. Dust on the faceplates also willattenuate the infrared beam as will an accumulation ofcondensation, frost, or ice on the faceplate.Like the microwave system, vegetation such asbushes, trees, grass, etc., will interfere with the infraredbeam, and ditches, gullies, or hills will allow areas wherethe passage of an inruder may be und:tected.The typical maximum distance between transnitterand receiver is about 100 meters.S. Vibration or Stress DetectorA variety of devices which detect strain or vibrationare available for use as fence protection systems.Although the devices vary greatly in design, eachbasically detects strain or vibration of the fence such asthat produced by an intruder climbing or cutting the5.44-2

..'ace. In the simplest devices, the vibration or strainmakes or breaks electrical continuity and therebygenerates an alarm.Vibration- or strain- detection devices for fenceprotection generally are susceptible to nuisance alarmsgenerated by wind-produccl vibration of the fences towhich they are attached. Rigid mounting of the fencewill lessen the propensity of the fence to vibrate andtherefore will reduce the frequency of nuisance alarms.However, making the fence too rigid will render thealarm system insensitive to an intruder. This situation isespecially common with post-mounted switch-contact-type alarm systems. The utilization of electronic signal.processing equipment in conjunction with signal-generating strain or vibration transducers can effectivelyreduce nuisance alarm rates without sacrificing scnsi.tivity to climbing or cutting the fence.Depending upon the variety of sensor, each sensorcan monitor a length of fence ranging from about onemeter to several hundred meters.C. REGULATORY POSITION1. Minimum Qualification for Perimeter IntrusionAlarm Systemsa. General(I) Electrical, All components-- sensors, elec-tronic processing equipment, power supplies, alarmmonitors-should be approved by the Underwriter'sLaboratory (UL) for fire safety. If alarm power isfurnished by public utility, the syst-em should containprovisions for automatic switchover to emergency bat-tery or generator power without generating alarms in theevent primary power is interrupted. Eimergency powershould be capable of sustaining operation for a minimumof 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> without replacing or recharging batteries orrefueling generators. If sufficient battery or fuel capacityis not attainable for 24-hour operation as stated above,additional batteries or fuel should be stored on siteexpressly for augmenting the emergency power supply.If emergency power is furnished by battery, all batteries(including stored batteries) should be maintained at aminimum of 90% of full charge by automatic battery-charging circuitry.(2) Tamper Indication. All enclosures forequipment should be equipped with tamper switches ortriggering mechanisms compatible with the alarm sys-tems. The electronics should be designed so thattamper-indicating devices remain in operation eventhough the system itself may be placed in the accessmode.* All controls that affect the sensitivity ofthe alarm system should be located within a tamper-*Access mode means the condition that maintains thesystem sensitive to Intrusion but that inhibits the audible (and insome cases visible) annunciation or an alarm.resistant enclosure. All signal lines connecting the a.larmrelays with alarm monitors should be supervised; if theprocessing electronics is separated from the sensorelements and not located wilhin the detection a;ea ofthe sensor elements, the signal lines linking the 3ensorsto the processing elec tro nics should also be supc vise ..All key locks or key-operated switche.%used to protect equipment and control.- should have UL-listed locking cylinders (see Regulatory (.uide 5.12,"General Use of Locks in tht lrotection of Facilities aodSpecial Nuclear Materiafl).(3) EvIronment. Pcrimeter intrusion 'latinsystems should be capable of operating throughout theclimatic extremes of the environs in which they are used;as ý,. minimum, the syst ems should be capable ofefiective operation between -35" and +50 'C. Corn-ponents that necessarily must be located out of doorsshould be protected from moisture damage by suchmethods as hermetic sealing or potting in an epoxycompound.(4) Alarm Conditions. Perimeter intrusionalarm systems should wenerate an alarm under any of thefollowing conditions:(a) Detection of stimulus or condition forwhich it was designed to react,(b) Failure of emergency power to piop-erly operate the system in the'event ofloss of primary power,(c) Indication of tampering (e.g., opening.shorting, or grounding of the sensorcircuitry) that can render the deviceincapable of normal operation.(d) Indication of tampering by activationof a tamper switch or other triggeringmechanism,(e) Failure or aging of any component(s)to the extent that the device is ren-dered incapable of normal operation.An automatic and distinctly recognizableindicat.4on should be generated by the alarm monitorupon switchover to emergency power. if primary poweris supplied from the central alarm station. In addition,for emergency power supplied by battery from thecentral alarm station, an automatic and disfinctly recog-nizable indication should be generated if. at any timeduring operation on primary power, the available emer-gency battery power is below 80% of rated capacity.Loss or reduction of power (either primaryor emergency) to the degree that the system is no longeroperating properly should result in an alarm condition orbe otherwise indicated in the central alarm station.*Signal supervision will be disussed in a replaory guidecurrendy undet development on interior intrusion &Lam syi-tems.5.44-3-I Placement of any portion of a perimeterIntrusion alarm system Into the access mode should beindicated automatically and distinctly by the alarmmonitor. Moreover, the segment(s) of the bystent placedin the access mode should be indicated clearly.(S) Installation. Perimeter intrusion alarmsystems generally may be loceicd ,n either side of theperimeter physical barrier. If, ir.,wvver, installation isoutside the perimetra barrier, a second barrier or fence(e.g., a cattle fence), should be erected so that the alarmsystem is located between the barriers. The secondbarrier or fence will serve to reduce the inmidence ofnuisance alarms from animals and passersby. Of course,fence protectlon systems must be located on a fence.Where possible, the perimeter should besegmented so that an'individual standing at one end of asegment will have a clear view of the entire segment. Inno case should any segment exceed 200 meters in length.Each segment should independently and uniquely indi-cate intrusion and should be capable of placement intothe access mode indepcndendy of the other segments.b. Microwave Perimeter Alarm System(1) Performance Criteria. A microwave peri.meter alarm system should be capable of detecting anintruder passing between the transmitter and receiver ata rate between 0.15 and IS meters per second, whetherwalking, running, jumping, crawling, or rolling. Themicrowave beani should be modulated, and the receivershould be frequency selective to decrease susceptibilityto receiver "capture". Generally, because of suscepti-bility to motion beyond the area to be protected,Doppler microwave systems should not be used asperimeter intrusion alarms.(2) Installation Criteria. The transmitters andreceivers should be installed on even terrain cicar oftrees, tall grass, and bushes. Each unit should bemounted rigidly at a distance of about 1 meter above theground. The distance between a transmitter and itsreceiver should be at least 70 meters. Neither thetransmitter nor the receiver should be mounted on afence. To prevent passage under the microwave beam inthe shadow of an obstruction, hills should be leveled,ditches filled, and obstructions removed so that the areabetween transmitter and receiver is clear of obstructionsand free of rises or depressions of height or depth greatertitan 1 5 cm. The clear area should be sufficiently wide topreclude generation of alarms by objects moving nearthe microwave link (e.g., personnel walking or vehiculartraffic). Approximate widths of the microwave patternshould be provided by the manufacturer.If the microwave link is installed inside androughly parallel to a perimeter fence or wall, thetransmitter and receiver should be positioned so as toprevent someone from jumping over the microwavebeam into'the protected area from atop the fenceor wall.Typically, a chain link security fence with an overallheight of 8 feet will necessitate a minimum of 2 metersbetween fence and the center of the microwave beam.Successive microwave links and comersshould overlap three meters to eliminate the dead spot(areas where movement is not detected) below andimmediately in front of transmitter and receivers. Theoverlap of successive links should be arranged so thatrece vez units are within t6e area protected by themicrowave beam.c. Ferrous Metal De~tector Perimeter AlarmSystem(1) Performance Criteria. A ferrous metaldetector perimeter alarm system should be able to detecta 400-pole.centimeter (CGS units) magnet moving at arate of 0.3 meter pei second within 0.3 netcr of a sensorcable. The detection system should be equipped withinhibitors to minirnf7e nuisance alarms due to electso-magnetic interference. Multiple inhibitors should be usedto prevent undetected simultaneous dexensitizing of theentire system.(2) Installation Criteria. To determine if theferrous metal deteclion system will operate in theproposed environment, a preengineering site surveyshould be made using an ehetrornagnetic detectionsurvey meter. This survey meter can be furnished by themanufacturer. if the electromagnetic disturbances arewithin the limits prescribed by the manufacturer, thistype of system can be used effectively. Special loopingconfigurations can be made in areas of high electro-magnetic irierference to reduce the incidents of nui-sance alarms.The sensing loops of electrical cable shouldbe buried in the ground according to the manufacturer'sstated depth. Multiple units (cable and amplifier) sht uldbe used to protect a perimeter. All associated buriedcircuitry should be buried in the detection zvne of thesensor and packaged in hermetically sealed containerm.The cable should be laid in accordance with themanufacturer's recommended geometrical configurationsto reduce nuisance alarms from external sources. Whencable is being installed in rocky soil. care should betaken to remove sharp rocks during backfilling over thecable.Inhibitors should be buried in the groundat least 6 meters from the cable inside the protectedperimeter.Continuous electromagnetic interferenceobstructs the detection of an intruder carrying metalover the buried cable by keeping the inhibitor activated,thereby preventing the alarm unit from responding to achange in flux. The device should therefore be used onlywhere the environment is relatively free of severeman-made electromagnetic interference. The cableshould never be installed close to overhead powertransmission lines. Moreover. the cable should be placed5.44-4 d0. IMPLEMENTATIONThe purpose of this wectioti is to piovide iuifor-niation to applicanits and Iiccen~.sct tcgifdingr the Regula-tory stafrs pluans for utilizing thi3 regubaury giidc.Except iW those casses in which 'lie appbcaj~tpruposes an aitc-rnaiive method1 fiur complying w.ithspecified portitin! of (ice CoMail IWJ% 11 S rcgulaikylms. "11cmethod described hereia, wall be used in. th,- ov-luatioi;of subnLmilsa in connecajion with spec-LiI nucicar materiallicense. onctag'rag ticense. or consti uction rwetuil atppliw~-lionsducictcý afite Augus~t 1. 19 75. WIf an zkpplicant mliose appbc.ation foi a specialnuclcar materiai licensc, an opetating licvnsc, or aConstniclion permit is dockcied on or Moefa August 1,'69757 wishcs it) use this regulatory guide in devcloping4ubtuiti-a~lot f ppiicstions. the per-tinent portions, of thle3ppkcat-ion will be cvaluated on flth: basis of~ this guide.5.44-6