1、Designation: G 63 99 (Reapproved 2007)Standard Guide forEvaluating Nonmetallic Materials for Oxygen Service1This standard is issued under the fixed designation G 63; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide applies to nonmetallic materials, (hereinaftercalled materials) under consideration for oxygen or oxygen-enrich
3、ed fluid service, direct or indirect, as defined below. It isintended for use in selecting materials for applications inconnection with the production, storage, transportation, distri-bution, or use of oxygen. It is concerned primarily with theproperties of a material associated with its relative su
4、sceptibil-ity to ignition and propagation of combustion; it does notinvolve mechanical properties, potential toxicity, outgassing,reactions between various materials in the system, functionalreliability, or performance characteristics such as aging, shred-ding, or sloughing of particles, except when
5、 these mightcontribute to an ignition.1.2 When this document was originally published in 1980, itaddressed both metals and nonmetals. Its scope has beennarrowed to address only nonmetals and a separate standardGuide G94has been developed to address metals.1.3 This standard does not purport to addres
6、s 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.NOTE 1The American Society for Testing and Materials takes
7、noposition respecting the validity of any evaluation methods asserted inconnection with any item mentioned in this guide. Users of this guide areexpressly advised that determination of the validity of any such evaluationmethods and data and the risk of use of such evaluation methods and dataare enti
8、rely their own responsibility.NOTE 2In evaluating materials, any mixture with oxygen exceedingatmospheric concentration at pressures higher than atmospheric should beevaluated from the hazard point of view for possible significant increasein material combustibility.2. Referenced Documents2.1 ASTM St
9、andards:2D 217 Test Methods for Cone Penetration of LubricatingGreaseD 566 Test Method for Dropping Point of LubricatingGreaseD 1264 Test Method for Determining the Water WashoutCharacteristics of Lubricating GreasesD 1743 Test Method for Determining Corrosion PreventiveProperties of Lubricating Gre
10、asesD 1748 Test Method for Rust Protection by Metal Preser-vatives in the Humidity CabinetD 2512 Test Method for Compatibility of Materials withLiquid Oxygen (Impact Sensitivity Threshold and Pass-Fail Techniques)D 2863 Test Method for Measuring the Minimum OxygenConcentration to Support Candle-Like
11、 Combustion ofPlastics (Oxygen Index)D 4809 Test Method for Heat of Combustion of LiquidHydrocarbon Fuels by Bomb Calorimeter (PrecisionMethod)G72 Test Method for Autogenous Ignition Temperature ofLiquids and Solids in a High-Pressure Oxygen-EnrichedEnvironmentG74 Test Method for Ignition Sensitivit
12、y of Materials toGaseous Fluid ImpactG86 Test Method for Determining Ignition Sensitivity ofMaterials to Mechanical Impact in Ambient Liquid Oxy-gen and Pressurized Liquid and Gaseous Oxygen Environ-mentsG88 Guide for Designing Systems for Oxygen ServiceG93 Practice for Cleaning Methods and Cleanlin
13、ess Levelsfor Material and Equipment Used in Oxygen-EnrichedEnvironmentsG94 Guide for Evaluating Metals for Oxygen Service2.2 Federal Standard:Fed. Test Method Std. 91B Corrosion Protection by Coat-ing: Salt Spray (Fog) Test32.3 Other Standard:BS 3N:100: 1985 Specification for General Design Require
14、-ments for Aircraft Oxygen Systems and Equipment41This guide is under the jurisdiction ofASTM Committee G04 on Compatibilityand Sensitivity of Materials in Oxygen Enriched Atmospheres and is the directresponsibility of Subcommittee G04.02 on Recommended Practices.Current edition approved March 15, 2
15、007. Published May 2007. Originallyapproved in 1980. Last previous edition approved in 1999 as G 63 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards
16、 Document Summary page onthe ASTM website.3Available from Superintendent of Documents, U.S. Government PrintingOffice, Washington, DC 20402.4Available from British Standards Institute (BSI), 389 Chiswick High Rd.,London W4 4AL, U.K., http:/www.bsi-.1Copyright ASTM International, 100 Barr Harbor Driv
17、e, PO Box C700, West Conshohocken, PA 19428-2959, United States.2.4 Other Documents:CGA Pamphlet G4.4 Industrial Practices for Gaseous Oxy-gen Transmission and Distribution Piping System5NSS 1740.15 NASA Safety Standard for Oxygen and Oxy-gen Systems63. Terminology3.1 Definitions:3.1.1 autoignition
18、temperaturethe temperature at which amaterial will spontaneously ignite in oxygen under specific testconditions (see Guide G88).3.2 Definitions of Terms Specific to This Standard:3.2.1 direct oxygen servicein contact with oxygen duringnormal operations. Examples: oxygen compressor piston rings,contr
19、ol valve seats.3.2.2 impact-ignition resistancethe resistance of a mate-rial to ignition when struck by an object in an oxygenatmosphere under a specific test procedure.3.2.3 indirect oxygen servicenot normally in contact withoxygen, but which might be as a result of a reasonablyforeseeable malfunct
20、ion, operator error, or process disturbance.Examples: liquid oxygen tank insulation, liquid oxygen pumpmotor bearings.3.2.4 maximum use pressurethe maximum pressure towhich a material can be subjected due to a reasonablyforeseeable malfunction, operator error, or process upset.3.2.5 maximum use temp
21、eraturethe maximum tempera-ture to which a material can be subjected due to a reasonablyforeseeable malfunction, operator error, or process upset.3.2.6 nonmetallicany material, other than a metal, or anycomposite in which the metal is not the most easily ignitedcomponent and for which the individual
22、 constituents cannot beevaluated independently.3.2.7 operating pressurethe pressure expected under nor-mal operating conditions.3.2.8 operating temperaturethe temperature expected un-der normal operating conditions.3.2.9 oxygen-enrichedapplies to a fluid (gas or liquid)that contains more than 25 mol
23、 % oxygen.3.2.10 qualified technical personnelpersons such as engi-neers and chemists who, by virtue of education, training, orexperience, know how to apply physical and chemical prin-ciples involved in the reactions between oxygen and othermaterials.3.2.11 reaction effectthe personnel injury, facil
24、ity dam-age, product loss, downtime, or mission loss that could occuras the result of an ignition.4. Significance and Use4.1 The purpose of this guide is to furnish qualified techni-cal personnel with pertinent information for use in selectingmaterials for oxygen service in order to minimize the pro
25、babil-ity of ignition and the risk of explosion or fire. It is not intendedas a specification for approving materials for oxygen service.5. Factors Affecting Selection of Material5.1 GeneralThe selection of a material for use withoxygen or oxygen-enriched atmospheres is primarily a matterof understa
26、nding the circumstances that cause oxygen to reactwith the material. Most materials in contact with oxygen willnot ignite without a source of ignition energy. When anenergy-input rate, as converted to heat, is greater than the rateof heat dissipation, and the temperature increase is continuedfor suf
27、ficient time, ignition and combustion will occur. Thusconsidered: the materials minimum ignition temperature, andthe energy sources that will produce a sufficient increase in thetemperature of the material. These should be viewed in thecontext of the entire system design so that the specific factors
28、listed below will assume the proper relative significance. Tosummarize: it depends on the application.5.2 Properties of the Material:5.2.1 Factors Affecting Ease of IgnitionGenerally, inconsidering a material for a specific oxygen application, one ofthe most significant factors is its minimum igniti
29、on temperaturein oxygen. Other factors that will affect its ignition are relativeresistance to impact, geometry, configuration, specific heat,relative porosity, thermal conductivity, preoxidation or passiv-ity, and “heat-sink effect.” The latter is the heat-transfer aspectof the material to the mass
30、 in intimate contact with it, withrespect to both the amount and the physical arrangement ofeach and to their respective physical properties. For instance, agasket material may have a relatively low ignition temperaturebut be extremely resistant to ignition when confined betweentwo steel flanges. Th
31、e presence of a small amount of an easilyignitable material, such as a hydrocarbon oil or a grease film,can promote the ignition of the base material. Accordingly,cleanliness is vital to minimize the risk of ignition (1).7Seealso Practice G93and Refs. 23.5.2.2 Factors Affecting PropagationAfter a ma
32、terial isignited, combustion may be sustained or may halt. Among thefactors that affect whether fire will continue are the basiccomposition of the material, the pressure, initial temperature,the geometric state of the matter, and whether the availableoxygen will be consumed or the accumulation of co
33、mbustionproducts reduce the availability of oxygen sufficiently to stopthe reaction. Combustion may also be interrupted by thepresence of a heat sink.5.2.3 Properties and Conditions Affecting Potential Result-ant DamageA materials heat of combustion, its mass, theoxygen concentration, flow condition
34、s before and after igni-tion, and the flame propagation characteristics affect thepotential damage if ignition should occur and should be takeninto account in estimating the reaction effect in 7.5.5.3 Operating ConditionsConditions that affect the suit-ability of a material include the other materia
35、ls of constructionand their arrangement in the equipment and pressure, tempera-ture, concentration, flow, and velocity of the oxygen. Pressureand temperature are generally the most significant, and theireffects show up in the estimate of ignition potential (5.4) andreaction effect (5.5), as explaine
36、d in Section 7.5Available from Compressed Gas Association (CGA), 4221 Walney Rd., 5thFloor, Chantilly, VA 20151-2923, http:/.6National Aeronautics and Space Administration, Office of Safety and MissionAssurance, Washington, DC.7The boldface numbers in parentheses refer to the list of references at t
37、he end ofthis standard.G 63 99 (2007)25.3.1 PressureThe pressure is important, not only becauseit generally affects the generation of potential ignition mecha-nisms, but also because it usually significantly affects thedestructive effects if ignition should occur. While generaliza-tions are difficul
38、t, rough scales would be as given in Table 1.NOTE 3While the pressure generally affects the reaction as indicatedin Table 1, tests indicate that it has varying effects on individualflammability properties. For example, for many materials, increasingpressure results in the following:(1) An increase i
39、n propagation rate, with the greatest increase in rate atlower pressures but with significant increases in rate at high pressures;(2)Areduction in ignition temperature, with the greatest decrease at lowpressure and a smaller rate at high pressure, however, it should be notedthat increasing autoignit
40、ion temperatures with increasing pressures havebeen reported for selected polymers, due to competing kinetics (4);(3) An increase in sensitivity to mechanical impact;(4) A reduction in oxygen index, as measured in an exploratory study(5), with sharper initial declines in materials of high oxygen ind
41、ex butwith only slight relative declines in general above 10 atmospheres and upto at least 20 atmospheres;(5) A negligible change in heat of combustion; and(6)An increase in the likelihood of adiabatic compression ignition, withthe greatest likelihood at the highest pressures.In the case of friction
42、, increased pressure may improve heatdissipation and make ignition at constant frictional energyinput less likely than at lower pressure. Increased pressure alsoreduces the likelihood of spark generation at constant electricfield strength through increased breakdown voltage values.5.3.2 TemperatureI
43、ncreasing temperature obviously in-creases the risk of ignition but does not generally contribute tothe reaction effect. The material should have a minimumignition temperature, as determined by an acceptable testprocedure, that exceeds the maximum use temperature (asdefined in 3.2.5) by a suitable s
44、afety margin.5.3.3 ConcentrationAs oxygen concentration decreasesfrom 100 %, the likelihood and intensity of a potential reactionalso decrease; therefore, greater latitude may be exercised inthe selection of materials.5.4 Ignition MechanismsFor an ignition to occur, it isnecessary to have three elem
45、ents present: oxidizer, fuel, andignition energy. The oxygen environment is obviously theoxidizer, and the material under consideration is the fuel.Several potential sources of ignition energy are listed below.The list is neither all-inclusive nor in order of importance norin frequency of occurrence
46、.5.4.1 FrictionThe rubbing of two solid materials resultsin the generation of heat. Example: the rub of a centrifugalcompressor rotor against its casing.5.4.2 Heat of CompressionHeat is generated from theconversion of mechanical energy when a gas is compressedfrom a low to a high pressure. This can
47、occur when high-pressure oxygen is released into a dead-ended tube or pipe,quickly compressing the residual oxygen that was in the tubeahead of it. Example: a downstream valve in a dead-endedhigh-pressure oxygen manifold.5.4.2.1 EquationAn equation that can be used to estimatethe theoretical maximum
48、 temperature that can be developedwhen pressurizing oxygen rapidly from one pressure andtemperature to an elevated pressure is as follows:Tf/Ti5 Pf/Pi#n1!/n(1)where:Tf= final temperature, abs,Ti= initial temperature, abs,Pf= final pressure, abs,Pi= initial pressure, abs, andn =CpCv5 1.40 for oxygen,
49、where:Cp= specific heat at constant pressure, andCv= specific heat at constant volume.Table 2 gives the theoretical temperatures which could beobtained by compressing oxygen from one atmosphere (abso-lute) and 20C to the pressures shown.5.4.3 Heat From Mass ImpactHeat is generated from thetransfer of kinetic energy when an object having relativelylarge mass or momentum strikes a material. Example: hammerstriking oxygen-saturated macadam.5.4.4 Heat from Particle ImpactHeat is generated fromthe transfer of kinetic and possib
