Significance and Use
The viscosity-gravity constant (VGC) is a useful function for the approximate characterization of the viscous fractions of petroleum. It is relatively insensitive to molecular weight and is related to a fluids composition as expressed in terms of certain structural elements. Values of VGC near 0.800 indicate samples of paraffinic character, while values close to 1.00 indicate a preponderance of aromatic structures. Like other indicators of hydrocarbon composition, the VGC should not be indiscriminately applied to residual oils, asphaltic materials, or samples containing appreciable quantities of nonhydrocarbons.
1.1 This test method covers the calculation of the viscosity-gravity constant (VGC) of petroleum oils having viscosities in excess of 5.5 mm2/s at 40°C (104°F) and in excess of 0.8 mm2/s at 100°C (212°F).
1.2 Annex A1 describes a method for calculating the VGC from Saybolt (SUS) viscosity and relative density.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3.1 The SI unit of kinematic viscosity is mm2/s.
1.3.2 Exception—Fahrenheit temperature units are used in this practice because they are accepted by industry for the type of legacy conversions described in this practice.
1.4 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.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
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)
D1298 Test Method for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method
D2140 Practice for Calculating Carbon-Type Composition of Insulating Oils of Petroleum Origin
D4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter
aromatic; density; kinematic viscosity; paraffinic;
ICS Number Code 75.080 (Petroleum products in general)
ASTM International is a member of CrossRef.
Citing ASTM Standards
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