Mass

Realization of the unit of mass

The unit of mass is defined by the mass of the International Kilogram Prototype (IKP). This is an artefact, which is a cylinder with the dimensions of 39 mm for diameter and height made out of an alloy of platinum and iridium.

The realization of the unit of mass at BEV is given by the copy No. 49 of the IKP, it’s mass is determined regularly by comparisons with the IKP or its most accurate copies,at the BIPM, Sèvres, Paris.

The secondary standards of the BEV are derived from the national prototype, i.e. the scale of masses from 1 mg to 500 kg is built up by means of mass comparators. Using the working standards traceable to them the weights and weighing instruments of the verification offices as well as the calibration and verification bodies are calibrated.

The calibrations are carried out by comparator weighing instruments and more and more by mass roboters on the base of a substitution procedure, at which the weight to be tested and the standard weight are compared consecutively with the same auxiliary weight and so the difference in the weighing results is determined.

National kilogram prototype No. 49
Laboratory – realisation of mass

Verification of weights and weighing instruments

Weights and weighing instruments are for various purposes subject to mandatory verification in Austria. The first verification of a new instrument is called initial verification. The verification of an unverified instrument is a new verification. Verification during the validity period is a reverification.

Since 30 October 2006 the Measuring instruments directive (MID) is applied in the member states of the EU. This directive regulates the first placing on the market of measuring instruments subject to mandatory verification by so called conformity assessment procedures. Automatic weighing instruments are covered by the MID, non-automatic weighing instruments are covered by the directive for non-automatic weighing instruments, which entered into force in Austria in the year 1994. Hence they can be placed on the market for the first time without further national type approval and initial verification. The assessment of conformity is equal to the initial verification.

Applicable as conformity assessment procedures are: For mechanical automatic weighing instruments the modules B+D, B+E, B+F, D1, F1,G or H1, for electro-mechanical automatic weighing instruments the modules B+D, B+E, B+F, G or H1, for electronic automatic weighing instruments or instruments containing software, respectively, the modules B+D, B+F, G or H1.

For non-automatic weighing instruments the procedures EU type approval, EU declaration of conformity, EU verification and EU unit verification are possible.

Automatic instruments for weighing road vehicles are not subject to a directive but to national regulations.

Weights are generally approved for verification if they fulfil certain regulations for the quality.

The new and subsequent verification of all weighing instruments and weights are subject to national regulations and is carried out in Austria by accredited verification bodies.The interval for subsequent verification is generally 2 years for weighing instruments and weights.

See Measuring Instruments Directive MI-006

See directive 90/384/EEC for Non-automatic weighing instruments

Gravity Zones in Austria

as published in the Amtsblatt für das Eichwesen Nr. 5/1996

 

The gravity zones are valid for non automatic weighing instruments (NAWIs) of class III,

depending on the number of divisions as given below (NAWIs adjusted to the given gravity

value may be placed anywhere within the relevant zone):

n = 1000 no marking of the place of use necessary
1000 < n = 3000  one zone „Österreich“ oder „A“ with g = 9,8065 m/s² is sufficient
3000 < n = 5000 Zone „B, NÖ, OÖ, W“ with g = 9,8073 m/s²
Zone „K, S, ST“ with g = 9,8065 m/s²
Zone „T,V”with g = 9,8051 m/s²
n > 5000 place of use to be marked (eg. „Innsbruck“)

Remark: For NAWIs of class IIII no marking of the place of use is necessary. NAWIs of class I or II have to be marked with the exact place of use.