Question: what is the difference between reid vapour pressure (rvp) and true vapour pressure (tvp)?
Answer: Reid Vapour Pressure (RVP) is the measure of the absolute vapour pressure exerted by a liquid at 100°F (37.8C) at a vapour-to- liquid ratio of 4:1. True Vapour Pressure (TVP) is vapour pressure of a mixture including any dissolved gases that may be present.