1.1 This test method covers the laboratory determination using a glass hydrometer in conjunction with a series of calculations, of the density, relative density, or API gravity of crude petroleum, petroleum products, or mixtures ofpetroleum and nonpetroleum products normally handled as liquids, and having a Reid vapor pressure of 101.325 kPa (14.696 psi) or less. Values are determined at existing temperatures and corrected to 15°C or 60°F by means of a series of calculations and international standard tables.
1.2 The initial hydrometer readings obtained are uncor- rected 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 expan- sion effect, alternate calibration temperature effects and to the reference temperature by means ofthe Petroleum Measurement Tables; values obtained at other than the reference temperature being hydrometer readings and not density measurements.
1.3 Readings determined as density, relative density, or API gravity can be converted to equivalent values in the other units or alternate 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.
1.4 The initial hydrometer readings determined in the labo- ratory shall be recorded before performing any calculations. The calculations required in Section 10 shall be applied to the initial hydrometer reading with observations and results reported as required by Section 11 prior to use in a subsequent calculation procedure (ticket calculation, meter factor calculation, or base prover volume determination).
