This International Standard describes a method for the determination of gauge vapour pressures of liquefied petroleum gas products (see clause 3) at temperatures within the approximate range of 35 “C to 70 “C. NOTES I Information on the vapour pressure of liquefied petroleum gases is required for the selection of properly designed storage vessels, shipping containers and customer utilization equipment, to ensure the safe handling of these products, and to ensure that maximum operating design pressures are not exceeded under the foreseen ambient operating conditions. 2 The vapour pressure of liquefied petroleum gases is an indirect measure of the lowest temperature at which initial vaporization can be expected to occur. It may also be considered to be an indirect indication of the most volatile constituent present in the product.