This document specifies a method for the determination of the vapour pressure, exerted in vacuo, by volatile, low viscosity petroleum products, components, ethanol blends up to 85 % (V/V), and feedstocks using a variable volume chamber. A dry vapour pressure equivalent (DVPE) is calculated from the vapour pressure. The conditions used in the test described in this document are a vapour-to-liquid ratio of 4:1 and a test temperature of 37,8 °C. The equipment is not wetted with water during the test, and the method described is therefore suitable for testing samples with or without oxygenates; no account is taken of dissolved water in the sample. This procedure calculates the partial pressure of the air dissolved in the test portion during the triple expansion process. It is suitable for samples with a DVPE between 15,7 kPa and 97,6 kPa; vapour pressures outside this range can be measured but the precision has not been determined. This document is applicable to fuels containing oxygenated compounds up to the limits stated in the relevant Council Directive 85/536/EEC [6], and for ethanol-fuel blends up to 85 % (V/V) ethanol. NOTE For the purposes of this document, the terms “% (m/m)” and “% (V/V)” are used to represent the mass and volume fractions respectively. WARNING — The use of this document can involve hazardous materials, operations and equipment. This document does not purport to address all of the safety problems associated with its use. It is the responsibility of users of this document to take appropriate measures to ensure the safety and health of personnel prior to application of the standard, and to determine the applicability of any further restrictions for this purpose.