Error Sources in Automatic Tank Gauging System

There are several sources of error which an automatic tank gauging system must overcome in order to accurately detect and measure a liquid leak from an underground storage tank. Some of these sources are: liquid temperature change measurement inaccuracies, tank chart errors, liquid temperature coefficient of expansion inaccuracies, absolute and differential liquid level measurement inaccuracies, liquid evaporation, tank thermal expansion, liquid expansion in tank piping, vapor pockets, tank deformation and groundwater pressure. This paper describes the occurrence and impact of these errors.