ASTM_F_2069_-_00.pdf

Designation:F 2069 00Standard Practice forEvaluation of Explosives Vapor Detectors1This standard is issued under the fixed designation F 2069;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.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 This practice is for the laboratory evaluation and selec-tion of explosives vapor detectors.2.Terminology2.1 Definitions:2.1.1 clear down timetime required for the detector toproduce no alarm at the IFMAL after an overload level.2.1.2 false negative ratioone minus the probability ofdetection.2.1.3 false positive ratioratio of the number of positivealarms to the total number of challenges when no explosivesvapor is present,where the number of challenges is large andthe instrument is set at the IFMAL.2.1.4 interferentnonexplosive substance,other than theexplosive being detected,that can mask the explosives andproduce a false negative decision or is identified as anexplosive,producing a false positive decision.2.1.5 interferent equivalent responsepositive or negativeresponse caused by a substance other than the explosive beingmeasured,and expressed in explosives equivalent concentra-tion units.2.1.6 interferent free minimum alarm level(IFMAL)alarmlevel that provides a 95%probability of detection at confi-dence level of 95%,at that setpoint,and no greater than 5%false positives,at confidence level of 95%,when challengedwith explosive free air at that setpoint.2.1.7 overload levelthat concentration that upon recycleof the detector in the absence of that mass,produces a signalabove the minimum alarm level.2.1.8 probability of detectionratio of the number ofalarms to the total number of challenges at a specifiedexplosive vapor concentration,where the number of challengesis 60 or greater and the instrument is set at the IFMAL Thisprobability takes into account other system variables that affectperformance,such as sample losses in inlets and preconcen-trators.2.1.9 response timethe amount of time required for thedetector to analyze the sample and produce a reading that is atleast 95%of the full response for that sample.2.1.10 samplethroughputnumberofdistinguishedsamples that can be obtained and processed by the detectorsystem in a given time period.2.1.11 sample timeamount of time it takes to obtain asufficient sample for introduction into the explosives detector.2.1.12 span driftvariance with time of the detector re-sponse to the upper calibration concentration level.2.1.13 temperature and humidity effectseffect of tempera-ture and humidity on the stability and drift of the zero and spancalibration of the detector.2.1.14 total analysis timetotal elapsed time from thesampling start until the system outputs a result.It is the sum ofthe sample time and response time.3.Significance and Use3.1 This practice establishes a method for characterizingexplosives vapor detectors in the laboratory.The practice doesnot set performance requirements.3.2 This practice is intended for use by the manufacturers ofexplosives vapor detection equipment and any organizationthat has the facilities and expertise to perform vapor calibra-tions.This practice relies upon the use of an explosives vaporgenerator unit to determine the applicable performance levelsof the explosives vapor detectors.3.3 This practice provides a method for evaluation of thefollowing parameters:3.3.1 Interferent free minimum alarm level,3.3.2 Probability of detection,3.3.3 False positive ratio,3.3.4 False negative ratio,3.3.5 Interference equivalent,3.3.6 Temperature and humidity effects,3.3.7 Sample time,3.3.8 Response time,3.3.9 Total analysis time,3.3.10 Sample throughput,and3.3.11 Overload level.3.4 Each user or evaluator may choose to evaluate a detectoronly for those parameters of interest to them.4.Reference Vapor Generator4.1 The reference calibrated explosives vapor generatorshall be one of the following vapor calibration units:(1)thepulsed vapor calibration unit constructed by the Idaho NationalEngineering Laboratory,Idaho Falls,Idaho,described in detail1This practice is under the jurisdiction of ASTM Committee F12 on SecuritySystems and Equipment and is the direct responsibility of Subcommittee F12.60 onControlled Access Security,Search,and Screening Equipment.Current edition approved Nov.10,2000.Published January 2001.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.in Ref(1);2(2)the continuous vapor calibration unit con-structed by Sandia National Laboratories,described in Ref(2);or(3)the continuous vapor calibration unit for higher vaporpressure explosives constructed by the National ResearchCouncil Canada described in Ref(3).5.Detector Evaluation5.1 A manufacturer of explosives vapor detectors mayconstruct or purchase a secondary vapor generation devicewhich can be used to measure