National measurement standards / National Metrology Institute
Metrosert is the National Metrology Institute of Estonia. We maintain and develop Estonian national measurement standards for length, mass, temperature and electrical quantities. The quality of numerous Estonian products and services is based on our measuring capability.
Length
The metre, symbol m, is the SI unit of length. It is defined by taking the fixed numerical value of the
speed of light in vacuum c to be 299 792 458 when expressed in the
unit m/s, where the second is defined in terms of the caesium frequency ΔνCs.
The Estonian laboratory of the national measurement standard for length realises a scale in the
range from 0.5 mm to 1000 mm using gauge blocks; in the range of up to 120 m, a laser interferometer is used.
Class K or 0 gauge blocks according to the standard ISO 3650:1998(E) are calibrated in the range from:
- 0.5 mm to 100 mm with the expanded measurement uncertainty of (0.05 + 0.5×L) µm
- 100 mm to 500 mm with the expanded measurement uncertainty of (0.2 + 0.9×L) µm
- 500 mm to 1,000 mm with the expanded measurement uncertainty of (0.2 + 2×L) µm
and measuring tapes in the range from:
- 1 mm to 120 m with the expanded measurement uncertainty of (0.06+0.015×L) mm.