1、Designation: G124 18Standard Test Method forDetermining the Combustion Behavior of Metallic Materialsin Oxygen-Enriched Atmospheres1This standard is issued under the fixed designation G124; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, 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.1. Scope1.1 This test method covers test apparatus and techniques todetermine the minimum test gas pressure and
3、 sample tempera-ture that supports self-sustained burning and the regression rateof the melting surface of a standardized sample of a metallicmaterial that has been ignited using a promoter.1.2 The data obtained from this test method are dependenton the precise test sample configuration and provide
4、a basis forcomparing the burning characteristics of metallic materials. Nocriteria are implied for relating these data for the suitability ofa materials use in any actual system.1.3 Requirements for apparatus suitable for this test methodare given, as well as an example. The example is not requiredt
5、o be used.1.4 This test method is for gaseous oxygen or any mixtureof oxygen with inert diluents that will support burning, at anypressure or temperature within the capabilities of the apparatusused.1.5 The values stated in SI units are to be regarded asstandard. The values given in parentheses afte
6、r SI units areprovided for information only and are not considered standard.1.6 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, health, and environmental pract
7、ices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and
8、 Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2G63 Guide for Evaluating Nonmetallic Materials for Oxy-gen ServiceG88 Guide for Designing Systems for Oxygen ServiceG93 Practice for Cleaning Methods and Cle
9、anliness Levelsfor Material and Equipment Used in Oxygen-EnrichedEnvironmentsG94 Guide for Evaluating Metals for Oxygen Service3. Terminology3.1 Definitions:3.1.1 burn length, nthe burn length is the length of thesample that has been consumed by combustion.3.1.1.1 DiscussionThe burn length is determ
10、ined by sub-tracting the post-test sample length from the pretest samplelength (which does not include the promoter length or regionused by the test sample support).3.1.2 flammable material, na material is defined in thisstandard as flammable if a standard rod sample burns morethan 3 cm (1.2 in.) ab
11、ove the promoter (1, 2).33.1.3 highest no-burn pressure, nthe maximum gas pres-sure (at a specified oxygen concentration and fixed sampletemperature) at which a material does not burn more than 3 cm(1.2 in.) above the promoter in a minimum of five tests.3.1.4 highest no-burn temperature, nthe maximu
12、msample temperature (at a specified oxygen concentration andpressure) at which a material does not burn more than 3 cm(1.2 in.) above the promoter in a minimum of five tests.3.1.5 igniter, na material used to ignite the promoter thatcan burn under an electrical influence, such as a small-diameterwir
13、e.1This test method is under the jurisdiction of ASTM Committee G04 onCompatibility and Sensitivity of Materials in Oxygen Enriched Atmospheres and isthe direct responsibility of Subcommittee G04.01 on Test Methods.Current edition approved Nov. 1, 2018. Published December 2018. Originallyapproved in
14、 1994. Last previous edition approved in 2010 as G124 10. DOI:10.1520/G0124-18.2For 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 Document Summary page o
15、nthe ASTM website.3The boldface numbers in parentheses refer to a list of references at the end ofthis standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationall
16、y recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.1.6 lowest burn pressure, nthe minimum gas pressure(at
17、a specified oxygen concentration and fixed sample tempera-ture) at which a material burns more than 3 cm (1.2 in.) abovethe promoter for one or more test specimens.3.1.7 lowest burn temperature, nthe minimum sampletemperature (at a specified oxygen concentration and pressure)at which a material burn
18、s more than 3 cm (1.2 in.) above thepromoter for one or more test specimens.3.1.8 promoter, nan optional material that can add supple-mental heat and increase the temperature to start burning of themetallic material being tested.3.1.9 regression rate of the melting interface, nthe aver-age rate at w
19、hich the solid-liquid metal (melting) interfaceadvances along the test sample length during a test.3.1.10 sample temperature, nthe initial temperature of thetest sample being evaluated.3.1.10.1 DiscussionVarious methods of measuring sampletemperatures are used. The method selected must be reportedwi
20、th test data.3.1.11 standard rod test sample, na 3.2 mm (0.125 in.)diameter rod with a minimum length of 101.6 mm (4 in.).3.1.12 threshold pressure, nthis term is historically usedto represent the definitions of either the lowest burn pressure orthe highest no-burn pressure.3.1.12.1 DiscussionIn thi
21、s standard, it represents the low-est burn pressure, which is used as the new term throughout.3.1.13 valid test, na test in which the igniter and/orpromoter combination has melted the bottom section of the testsample where the igniter and/or promoter is located.4. Summary of Test Method4.1 A standar
22、d rod sample of the material to be tested isvertically suspended in a chamber filled with pressurized testgas. The chamber contains sufficient oxygen so that not morethan 10 % of the oxygen will be consumed if the samplecompletely burns. A promoter (aluminum is most common,however titanium, carbon s
23、teel, and magnesium are also used)may be applied to the bottom of the rod to start burning of thematerial in conjunction with the igniter (typically Pyrofuse orNichrome wire).4The test chamber is pressurized to therequired test pressure and the sample is heated to the requiredtest temperature (if el
24、evated temperature is one of the param-eters).4.2 The test is initiated by ignition of the igniter wire/promoter (typically through resistive heating) so that the end ofthe test sample is melted away to produce a valid test withrelevant data collected, as specified.NOTE 1In 4.3 as subsequent samples
25、 are tested, only one parameter oftemperature or pressure is varied and the other held constant within thetolerance allowed by this test method. It is up to the user to determine ifthe purpose of the test is to determine burn/no-burn pressure or burn/no-burn temperature. Only one of these variables
26、should be changed duringa series of tests.4.3 If the sample is flammable, another standard sample rodis tested at a reduced test pressure or temperature. If the sampleis not flammable, testing continues until the sample is notflammable in a minimum of five tests at one set of conditions.It has been
27、shown, for a burn probability of less than 10 %, fiveno burn results provide a 41 % confidence level in the (noburn) result, whereas 22 no burn results provide a 90 %confidence level (for the same burn probability of 10 %). Athorough discussion of the burn probabilities and associatedconfidence leve
28、ls is given in Ref (3).NOTE 2Increasing the number of samples will always give a higherlevel of confidence and is recommended when possible. This methoddefines the highest no-burn pressure or temperature and the lowest burnpressure or temperature. The maximum no-burn (and burn) temperatureand pressu
29、re and regression rate of the melting interface can be deter-mined from the test data.5. Significance and Use5.1 This test method will allow comparisons of the burningcharacteristics of various metallic materials. The burningcharacteristics that can be evaluated include (1) burn andno-burn pressure,
30、 (2) burn and no-burn temperature, (3)regression rate of the melting interface, and (4) visual evalua-tion of the burning process of the test sample.6. Interferences6.1 Any materials inside the test chamber that may bake out,ignite/burn, or vaporize during the burning process at testtemperature/pres
31、sure may interfere with the chemistry of thefire propagation and subsequently affect burning.6.2 The specific atmosphere in the test chamber can have asevere chemical or thermodynamic effect, or both. Therefore,test gas contamination or diluents (such as argon, nitrogen,carbon dioxide, water vapor,
32、and others) can be importantfactors, so the oxygen gas purity and quantities and types ofdiluents should be specified in the data sheet.6.3 The standard test is conducted under non-flowing con-ditions. Tests conducted under flowing oxygen conditions maydramatically affect the test results depending
33、on the gasvelocity at the burning region. Although oxygen fires typicallyoccur under flowing conditions in service, the scope of this teststandard is to provide a relative means for comparing burningcharacteristics of metallic materials (1.2). Consequently, careshould be taken when considering that
34、a material is notflammable in given oxygen service conditions based solely onTest Method G124 data performed in static oxygen conditions.Performing this test standard under flowing conditions is notoutside the scope of this standard, but performing this test tocover all flowing conditions would be i
35、mpractical. Therefore,the non-flowing conditions outlined in this test standard wereselected as a basis for providing relative comparison ofmetallic materials.NOTE 3When comparing the burning characteristics of metallicmaterials using Test Method G124 test data, it is important to ensure thetest con
36、ditions (especially the variables identified in Section 6) werecomparable.4The trade name for aluminum-palladium wire is Pyrofuze. It is a registeredtrademark of the Pyrofuze Corp., 121 S. Columbus Ave., Mt. Vernon, NY 10553,and is available from them.G124 1827. Apparatus7.1 SystemA schematic of a t
37、ypical system is shown inFig. 1. Other designs may also be used if they fulfill thefollowing requirements.7.2 Test ChamberAcross-section of a typical test chamberis shown in Fig. 2. Appendix X1 provides criteria for estab-lishing the lowest test pressures that meet the stated criterion ofusing no mo
38、re than 10 % of the available oxidizer for variousvessel volumes. If the chamber cannot be made sufficientlylarge, an accumulator can be attached between the test chamberand the chamber isolation valve that contains more test gas.The test chamber (and accumulator if used) shall not contributeany che
39、mical interference to testing.7.3 Sample Holdercapable of securing the sample at thetop and supporting it in a vertical position.7.4 Temperature Sensorused to measure gas or sampletemperatures in the chamber, accurate to within 61% ofreading or accuracy otherwise noted.7.5 Pressure Transducerused to
40、 measure gas pressure inthe chamber, accurate to within 61 % of reading or accuracyotherwise noted.7.6 Liner (optional)a burn-resistant (for example, copperor ceramic) liner is recommended in the test chamber to serveas an internal shield to protect the chamber and componentsfrom the burning, molten
41、 slag, and other reaction productsproduced during sample burning.7.7 Sight Glass(optional for tests not determining eitherthe regression rate of the melting interface or visual evaluationof the burning process), capable of withstanding the maximumtest pressure anticipated (initial pressure plus pres
42、sure rise dueto heating during burning). Other methods of observing the testmay be possible, though direct observation is most common.7.8 Igniter Power Supplyelectrically isolated and capableof providing adequate current to initiate the ignition within 3 sof the application of power.7.9 Test Cella r
43、oom to house the test chamber, constructedof non-flammable material (such as concrete or metal) withsufficient strength to provide protection from explosion, pneu-matic release, or fire hazards. A continuous ventilation systemshall circulate fresh air in the test cell. The test cell shall becleaned
44、periodically to avoid contamination of the sample andequipment and minimize fire hazards.7.10 Piping Systemwhich purges, pressurizes, and ventsthe test chamber. The piping system shall be designed to permitremote test chamber purge, pressurization, and venting withoutunsafe exposure of personnel. It
45、 is recommended the testchamber be purged and pressurized through one line andvented through a separate line to minimize the chances of acontaminant migrating into the pressurization line, whichmight influence subsequent tests. It is also recommended that apressure relief device with an appropriate
46、setting be fitted to thepiping system and be able to communicate to the test chamber.NOTE 4Although the use of separate lines is preferred, it is not arequirement. Periodic inspection and cleaning of lines and valves shouldbe done to decrease the risk of cross contamination. A typical pipingsystem f
47、or this test is shown in Fig. 1.7.11 Control Areawhich will isolate test personnel fromthe test cell during tests. This control area shall be providedFIG. 1 Schematic of Typical SystemFIG. 2 Typical Stainless Steel Test Chamber Cross-SectionG124 183with the necessary control and instrumentation feat
48、ures toperform test chamber purge, pressurization and ventingoperations, and monitoring of the test chamber instrumentationduring the test.7.12 Data Acquisition Systemcapable of recording,storing, and accessing the pressure, temperature, and regres-sion rate data at a rate of ten samples per second
49、(minimum).It may also include a video recording device that displays the“real-time” burn phenomenon. The video recording with em-bedded timer, thermocouple sensor arrays, and ultrasonic rodlength measurements are some of the methods available fordetermination of the regression rate of the melting interface(see Annex A1).7.13 Heating System (for elevated temperature testingonly)which will heat the sample to the required initial testsample temperature range, without interfering with the otherfunctions of the test system or the test chamber integrity
