5.1 Excessive amounts of sodium can indicate the presence of materials that cause high wear of burner pumps and valves, and contribute to deposits of boiler heating surfaces.

1.1 This test method covers the determination of sodium in residual fuel oil by means of a flame photometer. Its precision in low ranges limits its application to samples containing more than 15 mg/kg sodium. Other elements commonly found in residual fuel oil do not interfere.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 This standard does not purport to address all of the safety problems 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. For specific hazard statements see 7.3, 7.5, 7.7, 9.2, 7.8, 7.9, and Note 3.

1.4 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.