ASTM D1298 for density of crude petroleum and liquid petroleum products
ASTM D1298 for density of crude petroleum and liquid petroleum products by hydrometer method
8. Procedure
8.1 Temperature of Test:
8.1.1 Bring the sample to the test temperature which shall be such that the sample is sufficiently fluid but not so high as to cause the loss of light components, nor so low as to result in the appearance of wax in the test portion.
NOTE 2 - The density, relative density or API gravity determined by the hydrometer is most accurate at or near the reference temperature.
NOTE 3 - The volume and density, the relative density, and the API corrections in the Petroleum Measurement Tables are based on the average expansions of a number of typical materials. Since the same coefficients were used in compiling each set of tables, corrections made over the same temperature interval minimize errors arising from possible differences between the coefficient of the material under test and the standard coefficients. This effect becomes more important as temperatures diverge from the reference temperature.
NOTE 4 - The hydrometer reading is obtained at a temperature appropriate to the physico-chemical characteristics of the material under test. This temperature is preferably close to the reference temperature, or when the value is used in conjunction with bulk oil measurements, within 3°C of the bulk temperature (see 5.3).
8.1.2 For crude petroleum, bring the sample close to the reference temperature or, if wax is present, to 9°C above its pour point or 3°C above its cloud point or WAT, whichever is higher.
NOTE 5 - For crude petroleum an indication of the WAT can be found using IP 389, with the modification of using 50 µL 6 5 µL of sample. The precision of WAT for crude petroleum using this technique has not been determined.
9. Apparatus Verification or Certification
9.1 Hydrometers and thermometers shall be verified in accordance with the procedures in Annex A1.
