【国外标准】 Standard Test Method for Classification of Film Systems for Industrial Radiography

4.1 This test method provides a relative means for classification of film systems used for industrial radiography. The film system consists of the film and associated processing system (the type of processing and processing chemistry). Section 9 describes specific parameters used for this test method. In general, the classification for hard X-rays, as described in Section 9, can be transferred to other radiation energies and metallic screen types, as well as screens without films. The usage of film system parameters outside the energy ranges specified may result in changes to a film/system performance classification.4.1.1 The film performance is described by contrast and noise parameters. The contrast is represented by gradient and the noise by granularity.4.1.2 A film system is assigned a particular class if it meets the minimum performance parameters: for Gradient G at D – D0 = 2.0 and D – D0 = 4.0, and gradient/noise ratio at D – D0 = 2.0, and the maximum performance parameter: granularity σD at D = 2.0.4.2 This test method describes how the parameters shall be measured and demonstrates how a classification table can be constructed.4.3 Manufacturers of industrial radiographic film systems and developer chemistry will be the users of this test method. The result is a classification table as shown by the example given in Table 2. Another table also includes speed data for user information. Users of industrial radiographic film systems may also perform the tests and measurements outlined in this test method, provided that the required test equipment is used and the methodology is followed strictly.(A) Family of films ranging in speed and image quality.4.4 The publication of classes for industrial radiography film systems will enable specifying bodies and contracting parties to agree to particular system classes, which are capable of providing known image qualities. See 8.2.4.5 ISO 11699–1 and European standard EN 584-1 describe the same method for classification of film systems for industrial radiography, but its class definitions and number of classes do not align exactly with this test method. International users of these standards should be aware of these differences for their particular applications.NOTE 1: ASTM research report E07–1005 contains documentation of technical methods used during the development of this test method.41.1 This test method covers a procedure for determination of the performance of film systems used for industrial radiography. This test method establishes minimum requirements that correspond to system classes.1.2 This test method is to be used only for direct exposure-type film exposed with lead intensifying screens. The performance of films exposed with fluorescent (light-emitting) intensifying screens cannot be determined accurately by this test method.1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.