ASTM_F_1398_-_93_2012.pdf

Designation:F139893(Reapproved 2012)Standard Test Method forDetermination of Total Hydrocarbon Contribution by GasDistribution System Components1This standard is issued under the fixed designation F1398;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()indicates an editorial change since the last revision or reapproval.INTRODUCTIONSemiconductor clean rooms are serviced by high-purity gas distribution systems.This test methodpresents a procedure that may be applied for the evaluation of one or more components considered foruse in such systems.1.Scope1.1 This test method covers the testing of components fortotal hydrocarbons(THC)contribution to a gas distributionsystem at ambient temperature.In addition,this test methodallows testing of the component at elevated ambient tempera-tures as high as 70C.1.2 This test method applies to in-line components contain-ing electronics grade materials in the gaseous form,such asthose used in semiconductor gas distribution systems.1.3 Limitations:1.3.1 This test method is limited by the sensitivity of currentinstrumentation,as well as by the response time of theinstrumentation.This test method is not intended to be used forcomponents larger than 12.7-mm(12-in.)outside diameternominal size.This test method could be applied to largercomponents;however,the stated volumetric flow rate may notprovide adequate mixing to ensure a representative sample.Higher flow rates may improve the mixing but excessivelydilute the sample.1.3.2 Different instrumental methods(such as flame ioniza-tion detector(FID),mass spectrometer(MS)will yield totalhydrocarbon(THC)levels that are not comparable due todifferent sensitivities to different molecular species.Hydrocar-bon contaminants of high-purity gas distribution systems canbe subdivided into two general categories:(1)noncondensablehydrocarbons(C4),that are present due to difficulty ofremoval and relative atmospheric abundance,and(2)condens-able hydrocarbons,that are often left behind on componentsurfaces as residues.Condensable hydrocarbons include pumpoils,degreasing agents,and polishing compound vehicles.1.3.3 Because of the tremendous disparity of hydrocarbonspecies,it is suggested that direct comparisons be made onlyamong data gathered using the same detection method.1.3.4 This test method is intended for use by operators whounderstand the use of the apparatus at a level equivalent to sixmonths of experience.1.4 The values stated in SI units are to be regarded as thestandard.The inch-pound units given in parentheses are forinformation only.1.5 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 to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.Specific hazardstatements are given in Section 5.2.Terminology2.1 Definitions:2.1.1 baselinethe instrument response under steady stateconditions.2.1.2glove bagan enclosure that contains a controlledatmosphere.A glove box could also be used for this testmethod.2.1.3 heat trace heating of component,spool piece,or teststand by a uniform and complete wrapping of the item withresistant heat tape.2.1.4 methane(CH4)equivalentthat concentration of CH4that causes the same instrument response as the sample.2.1.4.1 DiscussionThe calibration gas contains a knownconcentration of methane(CH4).Instrument response to zerogas and span gas defines the calibration curve for the analyzer.Instrument response to the sample is the summation of theresponse for each hydrocarbon reaching the detector.Theconcentration reported is the methane concentration,from thecalibration curve that corresponds to the instrument response to1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.10 on Contamina-tion Control.Current edition approved July 1,2012.Published August 2012.Originallyapproved in 1992.Last previous edition approved in 2005 as F1398 93(2005).DOI:10.1520/F1398-93R12.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 the sample.The samples concentration is equivalent to themethane concentration that would produce the same instrumentresponse.2.1.5 minimum detection limit(MDL)of the instrumentthelowest instrument response above zero detectable that isreadable by the instrument and at least two times the amplitudeof the noise.2.1.6 response timethe time required for the system toreach steady state after a measurable change in concentration.2.1.7 spool piecea null component,consisting of a straightpiece of electropolished tubing and appropriate fittings,used inplace of the test component to establish the baseline.2.1.8 standard conditions101.3 kPa,