Buying weighing scales can be a difficult thing to do, least of all when there are legalities to consider. In this post we will try to explain some of the laws surrounding trade approved scales and hopefully provide some insight into whether you need it for your business or organisation.

(I) WHAT IS NAWI?

The NAWI directive is what tells us what should and shouldn’t be approved. NAWI stands for Non Automatic Weighing Instrument and essentially means a weighing scale that has human interaction at some point along its process.

The NAWI directive tells us that certain weighing scales do not require an approval. This would cover items for use at home, for instance a kitchen scale or a bathroom scale. Even scales used in Gyms do not need to be approved.

On an industrial level, scales that are used for internal processes are also not required to be approved. If, however, you are charging or buying by weight and you are declaring a weight for this purpose then your scales need to be checked and verified by a qualified person, organisation or company, in other words Trade Approved.

(II) DIFFERENT CLASSES

There are 4 separate classes that govern this directive. Classes I & II would normally be used for a very high accuracy scale, as an example this could be used for weighing precious metals at a jewellers.

Class III is what most approvals fall under and would be used for the following applications for eg.:

  • Retail and industrial weighing machines
  • Supermarket checkout weighing systems and weighbridges
  • At post offices to have your parcel weighed to ship it out
  • Laboratory, pharmaceutical balances and medical weighing machines

Class IIII is generally used in medical environments where a patient’s weight needs to be checked or monitored, but at no stage can medication be prescribed based on weight given by a Class IIII approved scale, this would need to be done on a class III machine.

In short, if you are prescribing by weight, selling by weight or even buying by weight then your scales should be class III approved at the very least. If you are doing a stock take or even weighing your pet for eg then your scales do not need to be approved.

(III) LABELLING MARKS

Approved scales will generally have a green M on them and a CE mark. This does not make them approved, though, and simply means they could be should all criteria be met. To be approved your scale will also require the relevant paperwork as well as a tamper proof seal on the instrument to stop the calibration being affected without a re-verification being completed along with other identifying labels and marks.