5.2.1.2 Buoyancy Correction
The mass values observed by the weigh scales in the static weighing system are subject to buoyancy forces. According to Archimedes’ Law, to obtain the true mass of the water collected, the air and water densities are required. The true mass can be found using the following relationship: 1MTAWMMρρ=⎛⎞−⎜⎟⎝⎠ (8)
where MM is the apparent mass indicated by the scale, Aρ the air density, and Wρ is the water density. The buoyancy uncertainty for the WFCF was estimated in [1] and it is less than 0.0005%.
5.2.1.3 Splashes and Leaks
Liquid splashing from the diverter and weigh system and minor leaks from the pipework are usually apparent and are eliminated before calibrations start. Therefore, uncertainties for splashes or leaks are neglected.