Weighing Instruments

Automatic weighing instruments are tested according to international OIML recommendations.

National Swedish type approvals and international OIML-certificates are issued by SP for all types of automatic weighing instruments.

Today, the harmonising legislation in Europe for non-automatic weighing instruments has no equivalent in this area. However, all countries who are members of WELMEC (European cooperation in legal metrology) have agreed on accepting conformity with an OIML recommendation as the basis for a national type approval with little or no further examination where the instrument has already been granted approval in another signatory country.

According to WELMEC 4 (issue 2) March 1997, eighteen countries have signed the agreement. This means that a type approval from SP makes it easy to obtain national approvals for automatic weighing instruments in most European countries.

The relevant OIML recommendations are listed here:

• OIML R 50 "Continuous totalizing automatic weighing instruments",belt weighers
• OIML R 51 "Automatic catchweighing instruments (catchweighers)",checkweighers, weigh price labellers, wheel loader scales etc.
• OIML R 61 "Automatic gravimetric filling instruments"
• OIML R 106 "Automatic rail-weigh bridges"
• OIML R 107 "Automatic discontinuous filling instruments",hopper weighers

Non-automatic weighing instruments are tested according to the European standard EN 45501 and the international recommendation OIML R 76 from Organisation Internationale de Métrologie Légale. Type approval certificates accepted in all EU/EEA countries are issued by SP in accordance with the European Council Directive 90/384/EEC. OIML certificates can be issued for international use.

It is now also possible for a manufacturer to obtain an "open" type approval for weighing instruments consisting of an indicating device and approved load cells in certain types of load receptors.