1、Designation: D2863 121D2863 13Standard Test Method forMeasuring the Minimum Oxygen Concentration to SupportCandle-Like Combustion of Plastics (Oxygen Index)1This standard is issued under the fixed designation D2863; the number immediately following the designation indicates the year oforiginal adopt
2、ion 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.This standard has been approved for use by agencies of the Department of Defense.1 NO
3、TEEditorially corrected table reference in subsection 7.1.4 in December 2012.1. Scope*1.1 This fire-test-response standard describes a procedure for measuring the minimum concentration of oxygen, expressed aspercent volume, that will just support flaming combustion in a flowing mixture of oxygen and
4、 nitrogen.1.2 This test method provides three testing procedures. Procedure A involves top surface ignition, Procedure B involvespropagating ignition, and Procedure C is a short procedure involving the comparison with a specified minimum value of the oxygenindex.1.3 Test specimens used for this test
5、 method are prepared into one of six types of specimens (see Table 1).1.4 This test method provides for testing materials that are structurally self-supporting in the form of vertical bars or sheet upto 10.5-mm thick. Such materials are solid, laminated or cellular materials characterized by an appa
6、rent density greater than 15kg/m3.1.5 This test method also provides for testing flexible sheet or film materials, while supported vertically.1.6 This test method is also suitable, in some cases, for cellular materials having an apparent density of less than 15 kg/m3.NOTE 1Although this test method
7、has been found applicable for testing some other materials, the precision of the test method has not been determinedfor these materials, or for specimen geometries and test conditions outside those recommended herein.1.7 This test method measures and describes the response of materials, products, or
8、 assemblies to heat and flame undercontrolled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials,products, or assemblies under actual fire conditions.1.8 The values stated in SI units are to be regarded as standard. No other u
9、nits of measurement are included in this standard.1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of re
10、gulatorylimitations prior to use. Specific hazards statement are given in Section 10.1.10 Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed in conductingthese tests.NOTE 2This test method and ISO 4589-2 are technically equivalent when using the ga
11、s measurement and control device described in 6.3.1, with directoxygen concentration measurement.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD1071 Test Methods for Volumetric Measurement of Gaseous Fuel SamplesD1622 Test Method for Apparent Density o
12、f Rigid Cellular PlasticsD4802 Specification for Poly(Methyl Methacrylate) Acrylic Plastic SheetE176 Terminology of Fire Standards1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.30 on Thermal Properties.Current editi
13、on approved April 1, 2012Sept. 1, 2013. Published May 2012September 2013. Originally approved in 1970. Last previous edition approved in 20102012 asD2863 - 10.D2863 - 121. DOI: 10.1520/D2863-12E01.10.1520/D2863-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Cu
14、stomer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to
15、the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summar
16、y of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2 ISO Standards:3ISO 4589-2 Pla
17、sticsDetermination of Flammability by Oxygen IndexPart 2, Ambient TemperaturesISO 7823-1 Poly(Methylmethacrylate) SheetsTypes, Dimensions and CharacteristicsPart 1Cast SheetsISO 13943 Fire SafetyVocabulary3. Terminology3.1 Definitions3.1.1 For definitions of terms used in this test method refer to t
18、he terminology contained in Terminology E176 and ISO 13943.In case of conflict, the definitions given in Terminology E176 shall prevail.3.2 Definitions of Terms Specific to This Standard:3.2.1 ignitionthe initiation of combustion.3.2.2 oxygen index (OI)the minimum concentration of oxygen determined
19、by the method in 12.1, expressed as volumepercent, in a mixture of oxygen and nitrogen that will just support flaming combustion of a material initially at 23 6 2C underthe conditions of this test method.3.3 Symbols Specific To This Test Method:3.3.1 Cooxygen concentration in percent volume.3.3.2 CF
20、final value of oxygen concentration in percent volume.3.3.3 Cieach of the oxygen concentration percentages used during measurement of the last six responses in the NT series.3.3.4 Oneither the period or extent of burning exceeds the relevant limit specified in Table 2.3.3.5 Xthe period or extent of
21、burning exceeds the relevant limit specified in Table 2.3.3.6 NLseries of “X” or “O” results.3.3.7 NTseries of “X” or “O” results plus five (NT = NL + 5).3.3.8 *standard deviation of the oxygen concentration.3.3.9 dinterval between oxygen concentration levels in percent volume.3.3.10 ka factor to be
22、 determined from Table 3.3.3.11 nnumber of measurements of oxygen concentration.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.TABLE 1 Test Specimen DimensionsTestSpecimenTypeADimensionsMaterial FormLength,mmWidth,mmTh
23、ickness,mmI 80 to 150 10 0.5 4 0.25 for molding materialsII 80 to 150 10 0.5 10 0.5 for cellular materialsIIIB 80 to 150 10 0.5 # 10.5 for sheet materialsIVC 70 to 150 6.5 0.5 3 0.25 alternative size forself-supporting moldingor sheet materialsVB 140 5 52 0.5 #10.5 for flexible film or sheetVIBD 140
24、 to 200 20 0.02 to0.10for thin film; limited to filmthat can be rolled by thewire specified in 6.7A Test specimens of Types I, II, III, and IV are suitable for materials that areself-supporting at these dimensions. Test specimens of Form V and VI are suitablefor materials that require support during
25、 testing. Test specimens of Form VI aresuitable for film materials that can be rolled into a self-supporting specimen by theprocedure in 7.4.B Compare results obtained using Type III, V, and VI test specimens only to thoseobtained using specimens of the same form and thickness. It is assumed that th
26、eamount of variation in thickness for such materials will be controlled by otherstandards.C The Type IV (ASTM) specimen will eventually be discontinued in favor of theType 1 (ISO) specimen.D The test specimen of Type VI is suitable for thin film that is self-supporting whenit is rolled (see 7.4). Di
27、mensions in the table are of the specimen size from whichthe rolled form is made. If the film is very thin, it is possible that proper results willonly be obtained if two or more layers are combined in the preparation of the rollto obtain proper results.D2863 1324. Summary of Test Method4.1 A small
28、test specimen is supported vertically in a mixture of oxygen and nitrogen flowing upwards through a transparentchimney. The upper end of the specimen is ignited and the subsequent burning behavior of the specimen is observed to comparethe period for which burning continues, or the length of specimen
29、 burnt, with specified limits for each burning. By testing a seriesof specimens in different oxygen concentrations, the minimum oxygen concentration is determined.4.2 Three procedures are included in this test method. In ProcedureA, a complete assessment of the oxygen index is conductedusing top sur
30、face ignition. In Procedure B, a complete assessment of the oxygen index is conducted using propagating ignition.Procedure C provides a comparison with a specified minimum value of oxygen index and can be conducted using top surfaceignition or propagating ignition.5. Significance and Use5.1 This tes
31、t method provides for the measuring of the minimum concentration of oxygen in a flowing mixture of oxygen andnitrogen that will just support flaming combustion of plastics. Correlation with burning characteristics under actual use conditionsis not implied.5.2 In this test method, the specimens are s
32、ubjected to one or more specific sets of laboratory test conditions. If different testconditions are substituted or the end-use conditions are changed, it is not always possible by or from this test to predict changesin the fire-test-response characteristics measured. Therefore, the results are vali
33、d only for the fire-test-exposure conditionsdescribed in this test method.6. Apparatus6.1 Test Chimney. The test chimney consists of a heat-resistant glass tube of 75 to 100-mm inside diameter and 450 to 500-mmheight. The opening at the top of the chimney shall be restricted to provide an outlet of
34、40 6 2-mm diameter, either by providingan overhead cap or by designing the glass chimney appropriately. The bottom of the chimney, or the base to which the tube isattached, shall contain noncombustible material to evenly mix and distribute the gas mixture entering at this base. Glass beads 3to 5 mm
35、in diameter in a bed 80 to 100-mm deep have been found suitable. The chimney shall be mounted securely on the baseto prevent air leaks. One example of a design is shown in Fig. 1.NOTE 3It is helpful to place a wire screen above the noncombustible material to catch falling fragments and to aid in kee
36、ping the base of the columnclean.6.2 Specimen Holders6.2.1 Specimen Holder for Self-Supporting SpecimensAny small holding device that will support the specimen at its base andhold it vertically in the center of the chimney is an acceptable specimen holder. A typical arrangement (see Fig. 1) consists
37、 of alaboratory thermometer clamp inserted into the end of a glass tube held in place by glass beads or otherwise firmly supported.6.2.2 Specimen Holder for Specimens of Flexible Sheet or Film Materials that Require SupportAspecimen holder for flexiblefilm or sheet materials that require support sha
38、ll be able to support the specimen by both vertical edges in a frame equivalent tothat illustrated by Fig. 2, with reference marks at 20 and 100 mm below the top of the frame. The profile of the holder and itssupport shall be smooth to minimize induction of turbulence in the rising flow of gas.6.2.3
39、 Thin Film Rolling ToolIn order to prepare self-supporting specimens from thin films (see 7.4), use a 2 6 0.1-mmstainless steel rod with a 0.3 6 0.05-mm slit at one end, equivalent to that illustrated in Fig. 3. The actual specimen holder shallbe the one in 6.2.1.TABLE 2 Criteria for Oxygen Index Me
40、asurementsATest SpecimenType (See Table 1) Ignition ProcedureAlternative CriteriaPeriod ofBurningAfterIgnition(s)Extent of BurningBI, II, III, IV, and VI A(top surface ignition)180 50 mm below the topof the specimenI, II, III, IV, and VI B(propagating ignition)180 50 mm below theupper referencemarkV
41、 propagating ignition 180 80 mm below theupper referencemark (on the frame)A These criteria do not necessarily produce equivalent oxygen index results forspecimens of differing shape or tested using different ignition conditions orprocedures.B The extent of burning is exceeded when any part of the v
42、isibly burning portion ofa specimen, including burning drips descending the vertical faces, passes the levelindicated in the column.D2863 1336.3 Gas Measurement and Control Devices. Gas measurement and control devices shall be suitable for measuring theconcentration of oxygen in the gas mixture ente
43、ring the chimney with an accuracy of 60.5 %, by volume, of the gas mixture andfor adjusting the concentration of oxygen in the mixture with a precision of 60.1 %, by volume, of the gas mixture, when the gasvelocity through the chimney is 40 6 2 mm/s at 23 6 2C.6.3.1 A typical The system for gas meas
44、urement and control involves needle valves on individual and mixed gas supply lines,a paramagnetic oxygen analyzer that continuously samples the mixed gas, and a flowmeter flow meter to indicate when the gasflow through the chimney is within the required limits. See Annex A4 for an alternate system
45、for gas measurement.6.3.2 An alternative system of measurement and control does not use direct oxygen concentration measurements, but has provedsatisfactory. It includes the following: calibrated orifices, gas pressure regulators, and pressure gauges on the individual gas supplylines and needle valv
46、es and calibrated flowmeters on the individual gas supply lines.6.3.2 AnyThe system used for gas measurement requires calibration after assembly to ensure that the compounded errors of thecomponent parts do not exceed the requirements of 6.3.6.3.3 Means shall be provided for checking or ensuring tha
47、t the temperature of the gas mixture entering the chimney is 23 62C. If this involves an internal probe, its position and profile shall be designed to minimize induction of turbulence within thechimney.6.4 Flame Igniter. The flame igniter shall comprise a tube, with an inside diameter of 2 6 1 mm, t
48、hat can be inserted into thechimney to apply the test flame.6.4.1 The flame fuel shall be methane or natural gas of at least 97 % purity, without premixed air. The fuel supply shall beadjusted so that the flame projects 16 6 4 mm vertically downwards from the outlet when the tube is vertical within
49、the chimneyand the flame is burning within the chimney atmosphere.6.5 Timing Device. A timing device shall be provided, which is capable of measuring periods up to 5 min with an accuracy of60.5 s.6.6 Fume Extraction System. Afume extraction system shall be provided with sufficient ventilation or exhaust to remove fumesor soot expelled from the chimney without disrupting the gas-flow rate or temperatures in the chimney.NOTE 4If soot-generating materials are being tested, it is likely that the glass chimney, gas inlets, and inlet
