National Standard of Mass

Metrology of Mass

Mass metrology holds a significant position in the traceability and calibration system of measuring instruments in every country or metrological institute due to the following reasons:

1. Kilogram, symbol „kg“, is the unit of mass in the SI system. It is defined using the fixed numerical value of the Planck constant h, set to 6.626 070 15 × 10⁻³⁴ when expressed in J·s, which is equivalent to kg·m²·s⁻¹, where the meter and the second are defined using c (the speed of light) and Δν_Cs (the hyperfine transition frequency of cesium-133).

2. Mass measurement is among the most precise (with a relative measurement uncertainty reaching 10⁻⁹ to 10⁻¹⁰) and widely used types of measurement. The range of mass measurements in Slovakia spans from 10⁻⁷ g to 150 tons, and weight measuring instruments in practice (research, production, trade) are classified into five accuracy classes.

3. Mass, as the fundamental physical quantity in the SI system, directly contributes to the derivation and realization of values for other physical quantities (pressure, density, force, flow, and quantities in physical chemistry) and limits the accuracy of their measurements.

National Standard of Mass of the Slovak Republic

The National Standard of Mass includes:

• 2 PtIr standards of 1 kg,
• 9 steel standards of 1 kg,
• 7 sets of steel standards from 1 g to 1 kg,
• 3 sets of steel standards from 1 kg to 10 kg,
• 2 sets of platinum weights from 1 mg to 500 mg,
• 6 automatic devices with electronic comparator balances for mass standard calibration,
• 6 additional comparator balances, and
• Equipment for measuring of air density and weight volumes (part of the National Standard of Density).

Calibration of Mass Standards

• Calibration of steel standards of 1 kg using PtIr standards of 1 kg is performed on Mettler AT 1006 balances with air density measuring equipment (Klimet).
• Calibration of the mass scale is carried out using calibration schemes with redundant measurements processed using the least squares method.

Documents for download

• Osvedčenie (certifikát) (pdf, 1.2 MB)