Sampling and transforming of biometric data are performed at client based on information known at client only. When rising fuel exerts a force on the valve assembly pushing the float assembly upwards, the valve head attached to the float assembly seals directly against a valve seat on the underside of the modular flange, covering the vapor release aperture located through the flange, preventing fuel from escaping through the vent aperture. This allows the selection of a tube potential that provides a reduced radiation dose while still providing CT images of a sufficient quality.