This standard covers the specific procedures, equipment, and calculations required to determine the base prover volume (BPV), of both tank and displacement provers by the gravimetric method of calibration (GM).This standard presents both USC and SI units, and may be implemented in either system of units. The presentation of both units is for the convenience of the user, and is not necessarily the exact conversions. The system of units to be used is typically determined by contract, regulatory requirement, the manufacturer, or the user's calibration program.Throughout this document issues of traceability are addressed by references to National Institute of Standards and Technology (NIST). However, other appropriate national metrology institutes can be referenced.There is no intent to cover safety aspects of conducting the work described in this standard, and it is the duty of the user to be familiar with all applicable safe work practices. It is also the duty of the user to comply with all existing federal, state, or local regulations [e.g. the Occupational Safety and Health Administration (OSHA)] that govern the types of activities described in this standard, and to be familiar with all such safety and health regulations.