Scope
1.1 This practice describes procedures and recommendations for the validation of a total process analyzer system or its subsystems, or both, used in the direct measurement of physical or chemical characteristics of petroleum and petrochemical products. Procedures for initial validation and subsequent continuous quality assurance of system performance are described.
1.2 Validation is achieved by statistical assessment of results generated for common materials by the total analyzer system or its subsystem versus results generated by an ASTM or other established primary test method (PTM).
1.2.1 For analyzers used in product certification, the analyzer system precision determined by the statistical assessment is typically compared to the site precision for the PTM.
1.2.2 For other analyzer applications, analyzer system precision determined by the statistical assessment is compared to prespecified performance criteria based on the intended use.
1.3 Two procedures for validation are described: the line sample procedure and the validation reference material (VRM) injection procedure.
1.4 Only the analyzer system or subsystem downstream of the VRM injection point or the line sample extraction point is being validated by this practice.
1.5 The line sample procedure is limited to applications where material can be safely withdrawn from the sampling point of the analyzer unit without significantly altering the property of interest.
1.6 Validation information obtained in the application of this practice is applicable only to the type and property range of the materials used to perform the validation.
1.7 Procedures for conducting an initial validation are described. These procedures are typically conducted at installation or after major maintenance once the system mechanical fitness-for-use has been established.
1.8 Procedures for the continual validation of system performance are described. These procedures are typically applied at a frequency commensurate with the criticality of the application.
1.9 This practice applies if the process stream analyzer system and the primary test method are based on the same measurement principle(s), or, if the process stream analyzer system uses a direct and well-understood measurement principle that is similar to the measurement principle of the primary test method it is intended to predict.
1.10 This practice is not intended for use if the process stream analyzer system utilizes an indirect or mathematically modeled measurement principle such as chemometric or multivariate analysis techniques. Users should refer to Practice D 6122 for detailed validation procedures for these types of analyzer systems.
1.11 This practice does not address procedures for diagnosing causes of validation failure.
1.12 This practice does not address the methodology for establishing the correlation equation used to generate predicted PTM results using analyzer outputs, nor the expected prediction error. The former is assumed to have been correctly developed as part of the analyzer application development work.
1.13 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.
