American Petroleum Institute gravity scale | chemical measurement | Britannica (original) (raw)

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crude oil

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  In crude oil: Chemical and physical properties
  …petroleum industry, however, uses the American Petroleum Institute (API) gravity scale, in which pure water has been arbitrarily assigned an API gravity of 10°. Liquids lighter than water, such as oil, have API gravities numerically greater than 10. On the basis of their API gravity, crude oils can be classified…
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fossil fuel properties

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  In petroleum: Specific gravity
  The widely used American Petroleum Institute (API) gravity scale is based on pure water, with an arbitrarily assigned API gravity of 10°. (API gravities are unitless and are often referred to in degrees; they are calculated by multiplying the inverse of the specific gravity of a liquid at…
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