scope:

This International Standard specifies the calculations to be made to adjust the volume of a refrigerated hydrocarbon liquid, such as LPG or LNG, from the conditions at measurement to the equivalent volume of liquid or vapour at a Standard temperature and pressure, or to the equivalent mass or energy (calorific content). It applies to quantities of refrigerated hydrocarbon liquids stored in or transferred to or from tanks and measured under static storage conditions by tank gauges.

Using these procedures, the final quantity shall be expressed in terms of the following:

a) mass (see the note);

b) energy (calorific content) ;

c) equivalent volume of vapour under Standard conditions.

NOTE - The current practice for measurement of LPG is by apparent mass in air.

If it is required to express the volume of liquid at a standard temperature, the procedures and correlations to determine such quantities are given in clause 4. The Standard reference temperature for Petroleum products is 15 °C (see ISO 5024), but references are made to calculations involving other widely used reference temperatures, i.e. 20 °C.

If, for quantity calculations, the product density or the calorific value is required, this shall be either determined directly or calculated from the product composition analysis. The procedures for these subsidiary calculations are given in clauses 8 and 9.

The mandatory basic data and source references used in the calculation procedures are given in annexes A to F.