The e-mark on prepackages: the three rules

If you sell a fixed quantity in a package - 500 g of cheese, 1 kg of flour, 750 ml of sauce - you may put the e-mark next to it. That is not a quality mark from an authority but a declaration by yourself: this batch has been filled according to the European average quantity system. This is what that system requires and what you need to be able to demonstrate it.

What the e-mark says

The small e sits next to the nominal quantity on the package and means that the packer complies with the European rules for prepackages. The advantage is that the package may then be traded throughout the European Union without each country checking it separately. The system applies to packages from 5 g to 10 kg and from 5 ml to 10 l; outside that range other rules apply.

The e-mark is something different from the M mark. The M mark concerns the instrument: it has been verified. The e-mark concerns the contents of the package, and that is your own declaration.

The three rules

A batch of prepackages complies if all three are true:

1. the average content of the batch is not less than the nominal quantity;
2. no more than two per cent of the packages fall short by more than the tolerable negative error;
3. no single package falls short by more than twice that error.

The first rule is the core: on average the package must contain what it says. The second and third rules ensure that you do not reach that average by heavily overfilling one package and leaving another well short.

How much a package may fall short

The tolerable negative error depends on the nominal quantity. The smaller the package, the larger the percentage:

• 5 to 50 g: 9 per cent
• 50 to 100 g: 4.5 g
• 100 to 200 g: 4.5 per cent
• 200 to 300 g: 9 g
• 300 to 500 g: 3 per cent
• 500 to 1000 g: 15 g
• 1 to 10 kg: 1.5 per cent

At 500 g the error is therefore 15 g: no more than two per cent of the packages may be below 485 g, and none below 470 g. The same table applies to millilitres, with ml instead of g.

What you measure it with

The scale must be able to see the difference that matters. The rule of thumb is that the scale interval is at most one fifth of the tolerable error: at 500 g with a 15 g error you therefore weigh with 2 g or finer, and preferably with 1 g. A scale that reads in steps of 5 g simply cannot demonstrate the second and third rules.

If the instrument is used to check prepackages, it must also be verified and carry the green M mark - see legal metrology and your scale. We supply verified scales and checkweighing scales built for this purpose, verified from the factory; the initial verification is carried out by the manufacturer.

Tare: the empty weight is not constant

You weigh the filled package and deduct the empty weight. That empty weight varies per batch of film, box or jar, sometimes by more than the tolerable error itself. So determine the tare per batch of packaging material, with a sample of ten to twenty empty packages, and record the average. A scale with a tare memory per product holds that value, so the operator does not have to type it in.

What you must be able to show at an inspection

The inspector looks at two things: the instrument and your records. For the instrument, the M mark and the seal must be intact and the error must be within tolerance - a calibration certificate is the evidence for that. Your records must show that you really do check: how often you take a sample, how large it is, which tare you use and what the results were. The rules do not prescribe a fixed number of measurements; you must be able to demonstrate that the batch meets the three rules.

What we supply

Scales with a minimum and maximum limit that accept or reject without the operator having to calculate, with a count of the number of pieces weighed and the average. Verified where required, with a certificate where it helps. Indicators with a connection to a printer, a PC or your ERP system, so that the sample goes straight into your records. And we carry out calibration and repair in-house, on site or in our workshop; verification and re-verification are arranged through the manufacturer. See verification, calibration and repair.

How to set the limits and record the results is explained in checkweighing in production.

Frequently asked questions

Am I obliged to use the e-mark?

No. The e-mark is optional, not mandatory. If you apply it, you declare that the batch meets the three rules and the package may be traded throughout the EU. If you do not apply it, the national rules of each country where you sell apply.

Which scale do I need to check prepackages?

A scale whose scale interval is at most one fifth of the tolerable negative error of your package, and which is verified if you use it to check prepackages. At 500 g that means 2 g or finer.

What is the difference between the e-mark and the M mark?

The M mark is on the scale and means that the instrument has been verified. The e-mark is on the package and is your own declaration about the contents. You usually need both: the M mark on the scale you use to check the batch, the e-mark on what you sell.

Does this also apply if I weigh in the shop in front of the customer?

No. Then there is no prepackage but a weighing in the presence of the customer, and the rules for verified scales apply: the price follows from the weight weighed, so the scale must carry the M mark.

How often should I take samples?

The rules do not state a fixed number. You must be able to demonstrate that each batch complies, so the frequency depends on how stable your filling process is. It is common to take a sample per batch or per production hour, with more measurements as soon as the process changes: different material, different setting, different shift.