ASTM D1298-26

1.1 This test method covers the laboratory determination using a glass hydrometer and a separate temperature measuring device in conjunction with a series of calculations, of the density, relative density, or API gravity of crude petroleum, petroleum products, or mixtures of petroleum and nonpetroleum products normally handled as liquids, and having a Reid vapor pressure (Test Method D323) of 101.325 kPa (14.696 psi) or less. Values are determined at existing temperatures and corrected to values at 15 °C (or 60 °F) by means of a series of calculations and international standard tables.

1.2 The initial hydrometer readings obtained are uncorrected hydrometer readings and not density measurements. Readings are measured on a hydrometer at either the reference temperature or at another convenient temperature, and readings are corrected for the meniscus effect, the thermal glass expansion effect, alternative calibration temperature effects and to the reference temperature by means of calculations and Adjunct to D1250 Guide for the Use of the Petroleum Measurement Tables (API MPMS Chapter 11.1). Values measured (determined) at other than the reference temperature being hydrometer readings and not density measurements.

1.3 The initial hydrometer readings (including temperature) determined in the laboratory shall be recorded before performing any calculations. Then the calculations required in Section 10 shall be performed, and applied to the initial hydrometer reading with observations and results reported and documented as required by Section 11 prior to use in a subsequent calculation procedure, such as (ticket calculation, meter factor calculation, or base prover volume determination).

1.4 The initial hydrometer readings determined as density, relative density, or API gravity may be converted to equivalent values in the other units or alternative reference temperatures by means of Interconversion Procedures (API MPMS Chapter 11.5), or Adjunct to D1250 Guide for Petroleum Measurement Tables (API MPMS Chapter 11.1), or both, or tables, as applicable.

1.5 The values stated in SI units are to be regarded as standard.

1.6 Annex A1, Annex A2, and Annex A3 contains procedures for determining fit-for-service, verifying or certifying the equipment for this test method.

1.7 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.

1.8 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.