API MPMS 11.5.2:2009 pdf download

API MPMS 11.5.2:2009 pdf download.Manual of Petroleum Measurement Standards Chapter 11- -Physical Properties Data Section 5- -DensityWeight/Nolume Intraconversion Part 2- Conversions for Relative Density (60/60 °F).
3 Definitions and Abbreviations
3.1 Definitions
absolute density
The density of a substance is the mass of the substance occupying unit volume at a specified temperature at atmospheric pressure or equilibrium vapor pressure. Density as so defined is sometimes referred to as “true density” or as “density in vacuo,” or often just plain “density.” When reporting density, the units of mass and volume used and the temperature of the determination must be stated (e.g. kilograms per cubic metre or grams per millimetre at t °F or /°C). For the oil industry, if the temperature is unstated, standard temperature (60 °F or 15 °C) should be assumed.
3.1.2
API gravity
A term used by the petroleum industry to express the relative density of petroleum liquids (also see relative density).
The relationship between API gravity and relative density (formerly called specific gravity) is shown in Equation (1).
API gravity is a dimensionless number; as it is derived from absolute density, it is “in vacuo.”
3.1.3
apparent density
See density in air.
3.1.4
apparent weight
See weight in air.
3.1.5
density in air
Apparent weight of a substance occupying unit volume.
3.1.6
density in vacuo
See absolute density.
3.1.7
grams per cubic centimetre
An expression of density in SI (metric) units, also equal to grams per millilitre.
3.1.8
grams per millilitre
An expression of density in SI (metric) units, also equal to grams per cubic centimetre.
3.1.9
kilograms per cubic metre
An expression of density in SI (metric) units, numerically equivalent to grams per litre. This is the common unit of density currently used in the oil industry.
3.1.10
mass
An absolute measure of a particular quantity of matter. Mass is defined in terms of a standard mass, therefore, the mass of an object is simply a multiple of the mass standard. The mass of an object remains constant regardless of its location, whereas weight varies with altitude. The metric unit of mass is the kilogram (kg).
3.1.11
relative density
The ratio of the density of a substance at a specific temperature to the density of a reference substance at a reference temperature. When reporting results, explicitly state the temperatures of each, e.g. 20 °C14 °C. Formerly known as specific gravity.
3.1.12
specific gravity
See relative density.
3.1.13
true weight
See weight in vacuo.
3.1.14
volume correction factor
VCF
The ratio of a liquid’s density at temperature t and pressure p to its density at standard temperature 60 °F and 14.696 pounds per square inch absolute (psia) [or 15 °C and standard pressure 101 .325 kilopascals (kPa)] A liquid’s volume at temperature r can be converted to its volume at reference temperature by multiplying volume at temperature t by the VCF at temperature t. For more information, refer to API MPMS Ch. 11.1, Temperature and Pressure Volume Correction Factors for Generalized Crude Oils, Refined Products, and Lubricating Oils.
3.1.15
weight
A measure of gravitational force on an object. As gravitational force diminishes with distance from the center of the earth, weight is referenced to mean sea level. This is not to be confused with mass, which is independent of gravity and is directly proportional to the number of atoms or molecules present. The U.S. “customary” unit of weight is the pound (lb).
3.1.16
weight in air
The weight which a quantity of liquid would appear to have when weighed in the air against commercial weights which have been standardized so that each will have a weight in a vacuum equal to the nominal mass associated with it. During a weighing, the air exerts a net buoyancy force upon the liquid equal to the mass of air displaced by the liquid minus the mass of air displaced by the weights (for more information, see Section B.4).
3.1.17
weight in vacuo
The weight of a mass in a vacuum, with no air buoyancy effect.
3.2 Abbreviations