Legal-for-trade scales

When a scale must be verified

The rules for non-automatic weighing instruments list the applications for which a verified instrument is mandatory: determining mass in commercial transactions; calculating a toll, tariff, levy, premium or fine; weighing patients in medical practice; preparing medicines on prescription in the pharmacy and analyses in medical and pharmaceutical laboratories; and determining the price of prepacked products. Butcher, market trader, recycling company, wholesaler, GP surgery, pharmacy and the manufacturer who prepacks: all of them must use verified scales. If you only weigh for your own process, you do not; then calibration is the appropriate proof.

How to recognise a verified scale

On the data plate, next to the CE mark, there is an M in a rectangle with the last two digits of the year of verification and the number of the inspection body. Alongside that, the accuracy class (I, II, III or IIII), the Max and Min capacity, and the values e and d. The seals over the screws and the adjustment module must be intact: a broken seal invalidates the verification. What those marks mean exactly is explained under what is a verified scale.

Class III, II or I

Retail, bench, floor and pallet scales are Class III: the trade class, with a verification scale interval (e) from 0.1 g and between 500 and 10,000 scale intervals. Precision balances are Class II and analytical balances Class I; there the verification scale interval e is often ten times coarser than the readability d, and for legal purposes only e counts. That is why the product pages list the verification scale interval separately for a verified laboratory version. More under OIML classes explained.

How to order verified

For each model, the versions that can be supplied verified are marked; for OHAUS and KERN you can recognise them by the M in the type designation. Choose that version and the scale arrives verified from the factory, with the declaration of conformity. If you already have a scale that needs to be verified again, after a repair or because the seal has been broken, re-verification is arranged through the manufacturer. We are authorised by KERN, Adam, OHAUS, Baxtran and Gram to repair and recalibrate their instruments, including models we no longer sell.

By type

The verified versions are also grouped by category: verifiable bench scales, verifiable floor scales and verifiable medical scales. Retail scales can almost always be supplied verified: see retail scales.