Markings on measuring instruments

Verification mark

Indication of the next verification date

Non-automatic weighing instruments: Markings under the NAWI Directive

Marking of a non-verified ancillary equipment

Markings under the Measuring Instruments Directive (MID)

The Finnish type approval indication

EC markings under old directives

Markings of alcoholic spirits measures

Indication of the place of use of a weighing instrument

Indication of a rejected measuring instrument

 

Verification mark

The verification mark of a measuring instrument that has been verified either before its entry into service or in service is shown in Figure 1. The year and month of last verification is indicated on the mark.  

 

      Mark indicating verification

 

      Finnish seal mark         

Figure 1. Mark indicating verification.
In this example, the verification was performed in January 2012.

Figure 2. A Finnish seal mark.

 

The mark is visible in all measuring instruments after in-service verification.

If the stamp has been struck on a lead seal, etched on glass or branded on wood, there is no indication of the month. At the time of verification, it is possible to close with a seal (Figure 2) the parts of the measuring instrument that must not be tampered with after verification; for example, parts with which the display can be adjusted and the measuring result changed, must be sealed. If the seal is broken, the verification is no longer valid.

 

Indication of the next verification date

In addition to the verification mark, it is possible to affix an informative sticker to the measuring instrument, indicating the date when the next verification is due (Figure 3).

 

Indication of the next verification date 

Figure 3. Indication of the next verification date. In this example, the next verification is due in April 2012 at the latest.

 

Non-automatic weighing instruments: Markings under the NAWI Directive

Figure 4 shows the marking of a weighing instrument that complies with the requirements of the NAWI Directive.


Markings indicating the conformity of weighing instruments (Figure 4) include the CE marking with the last two digits of the manufacturing year (07), the identification number of the notified body (in this case, 0000) and a black letter M on a green background. If any of these are missing, the weighing instrument does not meet the requirements of the NAWI Directive.

 

 Markings indicating the conformity of a weighing instrument

Figure 4. Set of markings indicating the conformity of a weighing instrument.
In this example, the next scheduled verification of the weighing instrument is due at the end of 2010 at the latest.

 

The instrument is also equipped with a type plate that indicates its intended use and environmental requirements, such as accuracy class and operating temperature.

 

Marking of a non-verified ancillary equipment

It is possible to add non-verified ancillary equipment to calibrated weighing instruments, if they do not interfere with the operation of the instrument. Such equipment must be designated with a crossed M on a red background (see Figure 5) in order to indicate that verification does not apply to the data generated by the ancillary equipment.

 

Marking that limits the use of ancillary equipment.
Figure 5. Marking that limits the use of ancillary equipment. Verification does not apply to the data generated by this device.

 

Markings under the Measuring Instruments Directive (MID)

Measuring instruments approved according to the Measuring Instruments Directive (MID) are equipped with a conformity marking that consists of the CE marking, a supplementary metrology marking (M), the last two digits of the year when the marking was affixed (such as 07) and the identification number of the notified body (such as 0000) (Figure 6).

 

 Conformity with MID

Figure 6. Marking indicating conformity with MID.

 

Depending on the type of the measuring instrument, it may also be equipped with a type plate that gives further information on the intended use and recommended environment of the instrument.

 

The Finnish type approval indication

Measuring instruments that have been taken into service before the application of the NAWI Directive (in Finland: 1995) or MID (30 October 2006), or that do not fall under the scope of either directive, may have the Finnish type approval and the relevant markings. Type approvals are usually valid for 10 years after they have been issued. With respect to measuring instruments that belong to the scope of application of the NAWI Directive, those meeting the requirements of the old type approval may be taken into service until 30 October 2016.

 

Type-approved measuring instruments are equipped with a type plate in which a type approval indication is included. The Finnish type approval indication is in the form VJ.Z.XX.YY, where Z is the identifier of the kind of device in question (see Table), XX is an annual consecutive number and YY is the last two digits of the approval year (for example, VJ.E.1.94 means a Finnish approval of a cold-water meter). The letters ‘VJ’ stand for the words Vakaus/Justering (‘verification’ in Finnish and Swedish).

 

Table: Finnish identifiers of different kinds of measuring instruments

MEASURING INSTRUMENT

Z

Weighing instruments

no letter

Flow meters, liquids other than water

A

Measures of lenght

B

Grain moisture meters

C

Flow measuring systems, liquids other than water

D

Cold water meters

E

Flow sensors of heat meters

F

Temperature sensor pairs of thermal energy meters

G

Calculators of heat meters

H

 

EC markings under old directives

Most of pre-MID directives have been repealed, but due to transition periods, instruments that comply with these directives can still be taken into service, if old type approvals are valid at the time of their entry into service. These type approvals and initial verifications under old EC directives are valid also in Finland in case the approval is valid at the time of the instrument’s entry into service.

 

 EC type approval marking

EC type approval marking (in this case, D 89, meaning Germany 1989) and approval indication (in this case, 6.131.39). Such markings can be found on water flow meters, for example.

 EC initial verification mark

 

EC initial verification mark. Small letter ’e’ contains the identifier of the country and the area in the top half and the identifier of the body performing the verification in the lower half. Marking inside the hexagon indicates the verification year.

 EC initial verification mark

An alternative EC initial verification mark for measures of length.

Figure 7. EC markings under old directives.

 

Markings of alcoholic spirits measures

New alcoholic spirits measures must be placed on the market according to the Measuring Instruments Directive, in which case their markings are identical to that in Figure 6. However, alcoholic spirits measures that are in use often still have the initial verification marking shown in Figure 8 that consists of a picture of a crown, the last two digits of the year when the measure was calibrated, and the number of the body that performed the verification (xx).

 

Alcoholic spirits measure
Figure 8. Markings of an alcoholic spirits measure.

 

Indication of the place of use of a weighing instrument

Earth’s gravity impacts the measurement result of most weighing instruments. The value of gravitational acceleration varies somewhat in different parts of Earth, which means that in most cases, accurate electrical weighing instruments have to be verified either at or for the place of use. Verification can be performed in two phases, in which case a certificate is issued for the measures performed in the first phase, whereas the checks which the installation and location of the weighing instrument may have an effect on are performed in the second phase. The verification is not valid until the second inspection phase is complete. After this, it is not possible to move the verified weighing instrument very far, particularly not in the north-south direction, or the systematic error becomes too large. A notification sticker indicating the place of use (Figure 9) may be affixed on the weighing instrument.

 

  The place of use of a weighing instruments
Figure 9. Marking indicating the place of use of a weighing instrument.

 

Indication of a rejected measuring instrument

If, following the verification, the measuring instrument is rejected, a red rejection sticker (see Figure 10) may be attached to the instrument. At the same time, the body performing the verification must destroy the verification mark. If the measuring instrument is broken or its reading is found to exceed the permissible error margins, the instrument shall no longer be used, even if the next scheduled verification is not yet due. In this case, the instrument must be repaired, readjusted and verified. In case that the repair and readjustment is performed by an approved repair shop sealing the instrument with their own mark, the instrument may be used until the next scheduled verification.

 

A red rejection sticker

Figure 10. A red rejection sticker

 

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