Petroleum products and crude petroleum — Determination of vapour pressure — Reid method

This International Standard specifies a method for the determination of the vapour pressure of liquid petroleum

products consisting of essentially or wholly of hydrocarbon components, or containing oxygenated hydrocarbons of

specific types and at specified maximum concentrations. The method does not apply outside these concentration

levels, nor to any blends containing methanol or other oxygenated hydrocarbons not covered in note 1.

NOTE 1 The maximum concentration of ethers containing 5 or more carbon atoms is 15 % (V/V), and for ethanol is 10 %

(V/V). For higher alcohols, the maximum concentration is 7 % (V/V).

NOTE 2 For the purposes of this International Standard, the term "%(V/V)" is used to represent the volume fraction of a

material.

For petroleum products containing methanol, or other oxygenated hydrocarbons outside the scope of note 1, a dry

vapour-pressure test method should be used. For liquefied petroleum gases, ISO 4256 should be used. The test

method may be applied to volatile crude petroleum with a vapour pressure exceeding 10 kPa, although the

precision has not been evaluated.

Four procedures are described in this International Standard. Procedures A and