121Monthly volumetric average vapour pressure

121 Monthly volumetric average vapour pressure

121 Monthly volumetric average vapour pressure

(1) In this Subdivision, monthly volumetric average vapour pressure, of petrol, means the monthly volumetric average vapour pressure of the petrol calculated in accordance with this section.

(2) The monthly volumetric average vapour pressure of petrol supplied during a summer month by a petrol supplier must be calculated as follows—

(a) a sample must be taken from each batch of the petrol supplied in the month by the petrol supplier,

(b) the vapour pressure of each sample taken must be multiplied by a fraction that equals the volume of the petrol in the batch from which the sample was taken divided by the total volume of the petrol supplied in the relevant month,

(c) the figures calculated in accordance with paragraph (b) for each sample of petrol must be added together,

(d) the figure obtained in accordance with paragraph (c) is the monthly volumetric average vapour pressure.

(3) One test method only must be used in measuring vapour pressure to calculate the monthly volumetric average vapour pressure for a particular month.