1.1本试验方法涵盖了测量阈值极限条件的程序，以允许在压力、温度、流动条件、火灾传播方向和常见系统的各种其他几何特征的特定试验条件下，材料在各种氧化剂气体中的燃烧平衡。 1.2本试验方法以试验方法D2863-95为模板，并结合了其测量极限的程序，该极限是最常用试验条件下氧化剂浓度的函数。基本氧化剂极限（氧指数）程序的第8、9、10、11、13和14节直接引自试验方法D2863- 95.根据试验方法D2863-95报告的氧指数数据可以替代在类似条件下根据本标准收集的数据。 1.3本试验方法适用于各种形式材料的测试和排序。它还发现，对于预测材料在实际系统中证明“与氧相容”的前景，用处有限。然而，其结果不一定适用于任何在试验期间不能真实再现条件的条件。火灾极限是对行为特性而非物理特性的测量。 指南G63和G94介绍了这些数据的使用。 注1——虽然发现本试验方法适用于在一系列氧化剂和一系列稀释剂中测试一系列材料，但除适用于塑料的基本程序外，尚未确定许多此类组合和试样几何形状条件的精度。 注2——试验方法D2863-95已修订，修订后的试验方法已作为D2863-97发布。主要变化涉及样品尺寸、燃烧标准和测定氧指数的方法。 修订的目的是使试验方法D2863与ISO 4589-2一致。六个实验室使用D2863-95和D2863-97对自支撑塑料和多孔材料进行了比较循环试验。结果表明，在95%置信水平下，两种方法提供的均值没有差异。没有对薄膜进行比较测试。ASTM G4委员会的大多数成员赞成将D2863-95作为G125的主干，直到获得全面的比较数据。 1.4测试方法G124中规定了一组非常具体的测试条件，用于测量氧气中金属的耐火极限。 试验方法G124在其自身的一组试验条件下测量氧气中的最小压力极限。其细节不在本标准中复制。该程序有大量数据库可用，尽管其比试验方法D2863-95的数据库小得多。 附注3-- 警告: 在燃烧过程中，会产生气体、蒸汽、气溶胶、烟雾或这些物质的任何组合，这可能是危险的。 附注4-- 注意事项: 应采取足够的预防措施保护操作员。 1.5以国际单位制表示的数值应视为标准。 1.6 本基本标准应用于测量和描述材料、产品或组件在受控实验室条件下对热和火焰的响应特性，不应用于直接描述或评估材料、产品或组件在实际火灾条件下的火灾危险或火灾风险。然而，该测试结果可作为火灾风险评估的要素，该评估考虑了与特定最终用途火灾危险评估相关的所有因素。在这方面，本标准在预测尺寸接近试验条件的材料和部件的火灾行为方面比在很大程度上不同的系统（例如: 将测试棒与阀座进行比较，而不是将测试棒与房屋或颗粒进行比较） 1.7 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。 ====意义和用途====== 本试验方法用于测量一系列参数的最低条件（氧化剂和稀释剂流动混合物中的氧化剂浓度、压力、温度），这些参数将仅支持燃烧的持续传播。 对于表现出燃烧的材料，这是一个类似于较低可燃性的可燃极限 9 气体燃烧极限、可燃性上限和最小氧化剂( 1. ). 然而，与气体的易燃极限不同，在两相系统中，火焰上限和下限的概念没有意义。然而，通常可以为其他参数的变化确定极限，例如燃烧的最小氧化剂（氧化剂指数）、压力极限、温度极限等。这些数据的测量和使用类似于气体系统相应数据的测量和使用。 也就是说，这些限制适用于可能经历完全传播（平衡燃烧）的系统。在其他条件下或瞬态条件下，低于测量限值的成功点火和燃烧不排除在阈值以下。在一组条件下测得的可燃极限不一定是发生燃烧的最低阈值。因此，并不意味着这些数据与实际使用条件下的燃烧特性直接相关。

1.1 This test method covers a procedure for measuring the threshold-limit conditions to allow equilibrium of combustion of materials in various oxidant gases under specific test conditions of pressure, temperature, flow condition, fire-propagation directions, and various other geometrical features of common systems. 1.2 This test method is patterned after Test Method D2863-95 and incorporates its procedure for measuring the limit as a function of oxidant concentration for the most commonly used test conditions. Sections 8, 9, 10, 11, 13, and 14 for the basic oxidant limit (oxygen index) procedure are quoted directly from Test Method D2863-95. Oxygen index data reported in accordance with Test Method D2863-95 are acceptable substitutes for data collected with this standard under similar conditions. 1.3 This test method has been found applicable to testing and ranking various forms of materials. It has also found limited usefulness for surmising the prospect that materials will prove "oxygen compatible" in actual systems. However, its results do not necessarily apply to any condition that does not faithfully reproduce the conditions during test. The fire limit is a measurement of a behavioral property and not a physical property. Uses of these data are addressed in Guides G63 and G94. Note 1--Although this test method has been found applicable for testing a range of materials in a range of oxidants with a range of diluents, the accuracy has not been determined for many of these combinations and conditions of specimen geometry, outside those of the basic procedure as applied to plastics. Note 2--Test Method D2863-95 has been revised and the revised Test Method has been issued as D2863-97. The major changes involve sample dimensions, burning criteria and the method for determining the oxygen index. The aim of the revisions was to alignTest Method D2863 with ISO 4589-2. Six laboratories conducted comparison round robin testing on self-supporting plastics and cellular materials using D2863-95 and D2863-97. The results indicate that there is no difference between the means provided y the two methods at the 95 % confidence level. No comparison tests were conducted on thin films. The majority of ASTM Committee G4 favors maintaining the D2863-95 as the backbone of G125 until comprehensive comparison data become available. 1.4 One very specific set of test conditions for measuring the fire limits of metals in oxygen has been codified in Test Method G124. Test Method G124 measures the minimum pressure limit in oxygen for its own set of test conditions. Its details are not reproduced in this standard. A substantial database is available for this procedure, although it is much smaller than the database for Test Method D2863-95. Note 3-- Warning: During the course of combustion, gases, vapors, aerosols, fumes or any combination of these are evolved which may be hazardous. Note 4-- Precaution: Adequate precautions should be taken to protect the operator. 1.5 The values stated in SI units are to be regarded as the standard. 1.6 This basic standard should be used to measure and describe the properties of materials, products, or assemblies in response to heat and flame under controlled laboratory conditions and should not be used to directly describe or appraise the fire hazard or fire risk of materials, products or assemblies under actual fire conditions. However, results of this test may be used as elements of a fire risk assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard of a particular end use. The standard has more applicability in this regard at predicting the fire behavior of materials and components that are close in size to the test condition, than for systems that are much different (for example: comparing a test rod to a valve seat rather than comparing a test rod to a house or a particle) 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== This test method provides for measuring of the minimum conditions of a range of parameters (concentration of oxidant in a flowing mixture of oxidant and diluent, pressure, temperature) that will just support sustained propagation of combustion. For materials that exhibit flaming combustion, this is a flammability limit similar to the lower flammability 9 limit, upper flammability limit, and minimum oxidant for combustion of gases ( 1 ). However, unlike flammability limits for gases, in two-phase systems, the concept of upper and lower flame limits is not meaningful. However, limits can typically be determined for variations in other parameters such as the minimum oxidant for combustion (the oxidant index), the pressure limit, the temperature limit, and others. Measurement and use of these data are analogous to the measurement and use of the corresponding data for gaseous systems. That is, the limits apply to systems likely to experience complete propagations (equilibrium combustion). Successful ignition and combustion below the measured limits at other conditions or of a transient nature are not precluded below the threshold. Flammability limits measured at one set of conditions are not necessarily the lowest thresholds at which combustion can occur. Therefore direct correlation of these data with the burning characteristics under actual use conditions is not implied.