The legal units of measurement for volume are the cubic meter [m³] and the litre [l or L] which is derived from the cubic meter. Note that 1 l = 10-3 m³.
Realisation of the unit of liquid volume
Liquids are measured with volumetric standards (standard capacity measures). The capacity of a volumetric standard tallies with the unit of volume „1 litre“ (=1 dm3) or a multiple of it respectively. The unit of volume can not be directly realised. Instead the capacity of a volumetric standard is determined by mass or density measurement or by discharge of a liquid into an already calibrated volumetric standard.
Calibration of volume standards and storage tanks
Volumetric standards are standard capacity measures mostly made of glass, copper or stainless steel.
The capacity of volumetric standards (capacity measures) with nominal contents up to 1000 l is determined gravimetrically. In this procedure the volumetric standard to be calibrated is filled with a test liquid (water) up to a graduation line. After that the mass and density of the test liquid are determined and the capacity can be calculated from these two input quantities.
Capacities of volumetric standards with nominal contents up to 30 m³ can also be determined directly (volumetrically) by discharge into a calibrated standard.
The volume of storage tanks is either determined by gauging the capacity by litres with flow meters (wet measuring) or by using the optical method (dry measuring).
The capacity of volumetric measuring instruments made of glass, like volumetric flasks, graduated cylinders, burettes and pipettes is determined gravimetrically. The test liquid is distilled water.
Verification of capacity measures
Volumetric measuring instruments for liquids are subject to verification in Austria.
Storage tanks do not need a pattern approval and are verified if they comply with the requirements for the verification rules of storage tanks. The reverification period is 15 years.
Capacity measures made of glass do not need a pattern approval and are verified, if they meet the requirements for verification rules of volumetric flasks, graduated cylinder, burettes, volumetric pipettes and standard graduated pipettes. They are exempted from reverification.
Verification is carried out by the verification authority.