API MPMS 3.1B pdf download.Manual of Petroleum Measurement Standards Chapter 3—Tank Gauging 3.1B.1 Scope This standard covers level measurement of liquid hydro- carbons in stationary, aboveground, atmospheric storage tanks using automatic tank gauges (ATGs). The standard dis- cusses automatic tank gauging in general, accuracy, installa- tion, commissioning, calibration and veriÞcation of ATGs that measure either innage or ullage. It covers...