ASTM D6600-00 pdf download.Standard Practice for Evaluating Test Sensitivity for Rubber Test Methods.
5. Significance and Use
5.1 Testing is conducted to make technical decisions on materials, processes, and products. With the continued growth in the available test methods for evaluating scientific and technical properties, a quantitative approach is needed to select test methods that have high (or highest) quality or technical merit. The procedures as defined in this practice may be used for this purpose to make testing as cost effective as possible.
5.2 One index of test method technical merit and implied sensitivity frequently used in the past has been test method precision. The precision is usually expressed as some multiple ofthe test measurement standard deviation for a defined testing domain. Although precision is a required quantity for test sensitivity, it is an incomplete characteristic (only one half of the necessary information) since it does not consider the discrimination power for the FP (or constituent) being evalu- ated.
5.3 Any attempt to evaluate relative test sensitivity for two different test methods on the basis of test measurement standard deviation ratios or variance ratios, which lack any discrimination power information content, constitutes an in- valid quantitative basis for sensitivity, or technical merit evaluation. Coefficient of variation ratios (which are normal- ized to the mean) may constitute a valid test sensitivity evaluation only under the special condition where the two test methods under comparison are directly proportional or recip- rocally related to each other. If the relationship between two test methods is nonlinear or linear with a nonzero intercept, the coefficient of variation ratios are not equivalent to the true test sensitivity as defined in this practice. See discussion of example in X1.1.4. The figure of merit defined by test sensitivity and its various classifications, categories, and types as introduced by this practice permits an authentic quantitative test sensitivity evaluation.
6. Measurement Process
6.1 BriefOutline ofthe Measurement Process—A measure- ment process involves three components: (1) a (chemical or physical) measurement system, (2) a chemical or physical property to be evaluated, and (3) a procedure or technique for producing the measured value. The FP to be determined or evaluated has two associated adjuncts: a measured quantity or parameter, MP, that can take on a range of numerical values and a relationship between FP and MP ofthe general functional form MP = f(FP). An implicit assumption is that the procedure or technique must be applicable across a range of material or system property values.
6.2 The fundamental property may be a defined characteristic, such as the percentage of some constituent in a material or it may be defined solely by the measuring process itself. For this latter situation the measurement and the property are identical, and MP = FP or f = 1. This is the usual case for many strictly technological measurement operations or tests, for example, the modulus of a rubber. The MP = f (FP) relationship must be monotonic; for every value of MP there must be a unique single value for FP. The relationship must be specific for any particular measuring process or test, and, if there are two different processes or tests for evaluating the FP, the relationship is generally different for each test. 7. Development of Test Sensitivity Concepts
7.1 Test Domain—The scope ofany potential test sensitivity evaluation program should be established. Is the evaluation for a limited local testing situation, that is, one laboratory or test location Or are the results to be applied on a global basis across numerous domestic or worldwide laboratories or loca- tions? If local testing is the issue, the test measurements are conducted in one laboratory or location. For global testing, an interlaboratory test program (ITP) must be conducted. Two or more replicate test sensitivity evaluations are conducted in each participating laboratory and an overall or average test sensitivity is obtained across all laboratories. In the context of an ITP for global evaluation, each replicate sensitivity evalu- ation is defined as the entire set of operations that is required to calculate one estimated value for the test sensitivity. For additional background on the assessment of precision for the test sensitivity values attained, see A1.2 and also Practice D4483.ASTM D6600 pdf download.