3.3 Accuracy

The calibration of the base volume of a prover shall be carried out such that the expanded uncertainty of the calibration is significantly smaller than the acceptable criteria which is referred to as the maximum permissible error (MPE) in type approval tests and verification tests. The treatment of the expanded uncertainty and the acceptance criteria should follow OIML G 19:2017, the applicable OIML Recommendation, and/or an international standard. The expanded uncertainty shall be determined using an appropriate coverage factor () which is usually equivalent to two ().