Redistribution of hydrocarbons without losses between phases of the working environment at storage in the tank

The safety and respiratory fittings of tanks for storage of oil products can work at achievement of limiting pressure superfluous and vacuum in gas space and break tightness of the tank. Size of potential work of vΔP is calculated as a product of specific volume of working environment by pressure difference which is made of the sum of limiting pressures: a safety valve, vacuum and size of fluctuation of atmospheric pressure in a day. As a result the size of relative weight of hydrocarbon vapors is formed in gas space of the tank at the maximum change of temperature of the working environment ΔT in the tank without hydrocarbon losses.