4.1 Representative samples of petroleum and petroleum products are required for the determination of chemical and physical properties used to establish standard volumes, prices, and compliance with commercial and regulatory specifications. The treatment of samples from the time of collection until they are analyzed requires care and effort to maintain their compositional integrity. Samples of high RVP (unstabilized) hydrocarbons are required at many measurement points, for example offshore production, at the outlets of test separators or to allow calibration of a flowmeter. This practice also describes requirements associated with handling and mixing samples held within pressurized cylinders.

4.2 Practice D4057 (API MPMS Chapter 8.1), Practice D4177 (API MPMS Chapter 8.2), Practice D5854 (API MPMS Chapter 8.3), Practice D5842 (API MPMS Chapter 8.4), and Practice D8009 (API MPMS Chapter 8.5). The primary purpose of this suite of standards, is to ensure proper sampling and handling for custody transfer applications. There are a significant number of test methods that may be used to analyze the samples taken by techniques described in API MPMS Chapter 8.1 and 8.2. For samples that are taken for test methods outside the general scope of custody transfer covered by this practice, the personnel assigned to take the sample are responsible to refer to the test methods for additional critical information that may impact the sampling process, that is, specific container selection, transport methods, storage times, etc. Those requirements should be found in the appropriate test method.

1.1 This practice covers handling, mixing, and conditioning procedures that are required to ensure that a representative sample of the liquid petroleum or petroleum product is delivered from the primary sample container or container or both into the analytical apparatus or into intermediate containers.

1.2 Appendix X1 details the background information on the development of Table 1 used in performance testing. Appendix X2 provides guidance in the acceptance testing for water in crude oil. Appendix X3 provides a guide for materials of sample containers. Appendix X4 provides a summary of recommended mixing procedures. Appendix X5 provides a flow chart for sample container/mixing system acceptance test.

1.3 For sampling procedures, refer to Practices D4057 (API MPMS Chapter 8.1) and D4177 (API MPMS Chapter 8.2). Practice D5842 (API MPMS Chapter 8.4) covers sampling and handling of light fuels for volatility measurement, and D8009 (API MPMS Chapter 8.5).

1.4 It is recommended that the users of this practice perform the tests in Practice D4177 (API MPMS Chapter 8.2) before performing the test in this practice.

1.5 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.

1.6 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.