ASTM_F_1397_-_93_2012.pdf

Designation:F139793(Reapproved 2012)Standard Test Method forDetermination of Moisture Contribution by Gas DistributionSystem Components1This standard is issued under the fixed designation F1397;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 testing components for totalmoisture contribution to a gas distribution system at ambienttemperature.In addition,the test method allows testing atelevated ambient temperatures as high as 70C and of thecomponent moisture capacity and recovery.1.2 This test method applies to in-line components contain-ing electronics grade materials such as those used in semicon-ductor 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 fortest components 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 This test method is written with the assumption thatthe operator understands the use of the apparatus at a levelequivalent to six months 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 a component,spool piece,ortest stand by a uniform and complete wrapping of the item withresistant heat tape.2.1.4 minimum detection limit(MDL)of the instrumentthelowest instrument response detectable and readable by theinstrument and at least two times the amplitude of the noise.2.1.5 response timethe time required for the system toreach steady state after a change in concentration.2.1.6spool piecea null component,consisting of astraight piece of electropolished tubing and appropriate fittings,used in place of the test component to establish the baseline.2.1.7 standard conditions101.3 kPa,0.0C(14.73 psia,32F).2.1.8 test componentany device being tested,such as avalve,regulator,or filter.2.1.9 test standthe physical test system used to measureimpurity levels.2.1.10 V-1,V-2inlet and outlet valves of bypass loop,respectively.2.1.11 V-3,V-4inlet and outlet valves of test loop,respec-tively.1This 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 F1397 93(2005).DOI:10.1520/F1397-93R12.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 2.1.12zero gasa purified gas that has an impurityconcentration below the MDL of the analytical instrument.This gas is to be used for both instrument calibration andcomponent testing.2.2 Abbreviations:2.2.1 MFCmass flow controller.2.2.2 ppbvparts per billion by volume assuming ideal gasbehavior,equivalent to nmole/mole(such as nL/L).The sameas molar parts per billion(ppb).2.2.3 ppbwparts per billion by weight(such as ng/g).2.2.4 ppmvparts per million by volume assuming idealgas behavior,equivalent to mole/mole(such as L/L).Thesame as molar parts per million(ppm).2.2.5 ppmwparts per million by weight(such as g/g).2.3 Symbols:2.3.1P1The inlet pressure measured upstream of thepurifier and filter in the test apparatus.2.3.2 P2The outlet pressure measured downstream of theanalyzer in the test apparatus.2.3.3 Q1the bypass sample flow not going through theanalytical system.2.3.4 Q2the total sample flow through the analyticalsystem.2.3.5Qsthe flow through the spool piece or component.2.3.6 Tathe temperature of the air discharged by theanalyzers cooling exhaust.2.3.7 Tsthe temperature of the spool piece or component.2.3.7.1 DiscussionThe thermocoup