RVP
Reid Vapor Pressure is a vapor pressure for liquid products as determined by ASTM test procedure D- 323. The Reid vapor pressure is defined as pounds per sq in. at 100°F.
The RVP is always less than the true vapor pressure at 100°F.
TVP
True vapor pressure is the pressure at which the gas and liquid in a closed container are in equilibrium at a given temperature.
The true vapour pressure is for everything by gas, liquid, solids, and contaimenets.
The graphical method of converting from RVP to TVP is an approximation and is generally more accurate for lighter components IN GPSA.
. TVP = (1.07) (RVP) + 0.6
WORKING PRESSURE
A design working pressure can be determined to prevent breathing, and thereby save standing storage losses.
Generally there are regulatory requirements specifying the type of storage tank to be used, based on the storage tank capacity and the vapor pressure of the product being stored.