The unit of mass, kilogram (kg) is one of the seven base units in the SI unit system and is still defined in terms of the international kilogram prototype K, which is kept at the BIPM in Sèvres outside Paris. In the past few years, the efforts to redefine the kilogram in terms of fundamental constants have been intensified. It is hoped that a new definition of the kilogram would be sanctioned at the General Conference of Weights and Measures in 2011.
From the kilogram, a large number of other SI units are derived, including the units of force (newton, N) and pressure (pascal, Pa). In practice, the kilogram is also used to establish traceability of the measurement of volume (m3) and amount-of-substance (mol). The metrological field Mass comprises all those quantities, for which the traceability to the SI is established primarily through a mass standard.
Within DANIAmet, the field Mass is divided into three subfields: 1) Mass measurement, 2) Force & pressure, and 3) Volume. Each of these subfields are taken care of by a member of DANIAmet-NMI:
Mass measurement at Danish Fundamental Metrology
It is convenient to use mass to quantify materials and substances in solid, powdered or liquid form. In industry, mass measurement (weighing) is often used in the production as well as in the price settlement of purchased and produced goods. Correct mass measurement is obviously important for the price settlement, because even a small error in a weighing instrument might result in a large error in the settlement of accounts over an extended period of time. In the production, precise mass measurements also plays an important role, since more accurate measurements improve the production control leading to products of better uniformity at the required level of quality.
Danish Fundamental Metrology was appointed as primary laboratory for measurement of mass in 1995. The primary laboratory holds the national copy (no. 48) of the international kilogram prototype K. Traceable to this, Danish Fundamental Metrology offers accredited calibration of mass standards (weights) in the interval from 1 mg to 20 kg with an uncertainty that is internationally competitive.
Danish Fundamental Metrology
DK-2800 Kongens Lyngby
Phone: +45 45 25 5866
Fax: +45 45 93 1137
Force and pressure calibration at FORCE Technology
Force-calibration is very important in areas as construction industry, engineering and shipbuilding enterprises. Pressure-measurement is a important part of the process control in in among others pharmaceutical industry, chemical industri and the off shore sector.
FORCE Technology was appointed as National Metrology Institute in 1990 in the fields Force and Pressure with reference to PTB in Germany. The Force-laboratorty calibrates Force in compression in the range 0,1 – 5000 kN and in tension in the range 0,1 – 1000 kN. The pressure-laboratory calibrates vacuum meters from 0,135 Pa til atmos pressure, absolute pressure, differens pressure og gauge pressure in a wide measuring range, such as micro pressure ±1500 Pa and high pressure 500 MPa.
Park Allé 345
DK. 2605 Brøndby
Phone: +45 43 26 7160
Fax: +45 43 26 6701
Volume and density at FORCE Technology
Volume measurements are a part of everyone’s everyday life. Many quantities are determined from volume, injection of medication, liquid food, waste bin, containers etc. Right from ancient times the volume requirement has been significant for settlement. Example: For payment for a barrel of grain.
In 1997 the laboratory was appointed to NMI for Volume. With help from the gravimetric methods the laboratory perform volume measurements from 0,8 µl to 550 l and by decantation up to 40 m3.
Volume measurements based on mass and density.
In 1997 the laboratory was appointed to NMI for Density. With help from the gravimetric methods the laboratory perform density measurements of liquids in the area of 600 kg/m3 to 2000 kg/m3 as by oscillation (fluctuations of a u-tube) up to 900 – 1100 kg/m3.
The laboratory also provides density measurements in gas. The density measurements are based on the Archimedes’ principle that the displacing fluid correspond to the volume of the immersed body.
Park Allé 345
DK. 2605 Brøndby
Phone: +45 42 62 77 52
Fax: +45 43 26 7011