ASTM D4052 for density, relative density and API gravity of liquids
ASTM D4052 standard test method for density, relative density, and API gravity of liquids by digital density meter
1. Scope
1.1 This test method covers the determination of the density, relative density, and API Gravity of petroleum distillates and viscous oils that can be handled in a normal fashion as liquids at the temperature of test, utilizing either manual or automated sample injection equipment. Its application is restricted to liquids with total vapor pressures (see Test Method D5191) typically below 100 kPa and viscosities (see Test Method D445 or D7042) typically below about 15000 mm2/s at the temperature of test. The total vapor pressure limitation however can be extended to >100 kPa provided that it is first ascertained that no bubbles form in the U-shaped, oscillating tube, which can affect the density determination. Some examples of products that may be tested by this procedure include: gasoline and gasoline-oxygenate blends, diesel, jet, basestocks, waxes, and lubricating oils.
1.1.1 Waxes were not included in the 1999 interlaboratory study (ILS) sample set that was used to determine the current precision statements of the method, since all samples evaluated at the time were analyzed at a test temperature of 15ºC. Wax samples require a temperature cell operated at elevated temperatures necessary to ensure a liquid test specimen is introduced for analysis. Consult instrument manufacturer instructions for appropriate guidance and precautions when attempting to analyze wax sample types. Refer to the Precision and Bias section of the method and Note 6 for more detailed information about the 1999 ILS that was conducted.
1.2 In cases of dispute, the referee method is the one where samples are introduced manually as in 6.3 or 6.4, as appropriate for sample type.
1.3 This test method should not be applied to samples so dark in color that the absence of air bubbles in the sample cell cannot be established with certainty. For the determination of density in crude oil samples use Test Method D5002.
1.4 The values stated in SI units are regarded as the standard, unless stated otherwise, such as the "torr" units of pressure in Eq 1. The accepted units of measure for density are grams per millilitre (g/mL) or kilograms per cubic metre (kg/m3).
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 and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see 7.4, 7.5, and 10.3.
2. Referenced Documents
2.1 ASTM Standards:
D287 Test Method for API Gravity of Crude Petroleum and Petroleum Products (Hydrometer Method)
D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
D1193 Specification for Reagent Water
D1250 Guide for Use of the Petroleum Measurement Tables
D1298 Test Method for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D4377 Test Method for Water in Crude Oils by Potentiometric Karl Fischer Titration
D5002 Test Method for Density and Relative Density of Crude Oils by Digital Density Analyzer
D5191 Test Method for Vapor Pressure of Petroleum Products (Mini Method)
D7042 Test Method for Dynamic Viscosity and Density of Liquids by Stabinger Viscometer (and the Calculation of Kinematic Viscosity)
3. Terminology
3.1 Definitions:
3.1.1 adjustment - the operation of bringing the instrument to a state of performance suitable for its use, by setting or adjusting the density meter constants.
3.1.1.1 Discussion - On certain newer, commercially available digital density analyzer instruments, an adjustment may be made rather than calibrating the instrument. The adjustment procedure uses air and redistilled, freshly boiled and cooled water as standards to establish the linearity of measurements over a range of operating temperatures.
3.1.2 calibration - set of operations that establishes the relationship between the reference density of standards and the corresponding density reading of the instrument.
3.1.3 density - mass per unit volume at a specified temperature.
3.1.4 relative density - the ratio of the density of a material at a stated temperature to the density of water at a stated temperature.
