Volume from level

I believe there are API publications on tank strapping, calibration, etc.

Your tank should have calibration tables or you can get it calibrated by a certified agency.

Otherwise cross sectional area times height gives volume. Find a correlation of your products density vs temperature and simply multiply for the mass.

Thanks.
I have seen such calibration tables and I have noticed they include many correction factors for density, roof, etc...
I was then wondering if it exists any ASTM, API or ISO standards that define and harmonize such corrections.

"We don't believe things because they are true, things are true because we believe them."

API Std 2552, Measurement and Calibration of Spheres and Spheroids
API MPMS Chapter 2.2B, Calibration of Upright Cylindrical Tanks Using the Optical Reference Line Method
API Std 2555, Liquid Calibration of Tanks
API 2551, Standard Method for Measurement and Calibration of Horizontal Tanks
From a quick perusal of API's site. There are additional standards that may be of interest.