Average quantity system for packers and importers

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The Weights and Measures (Packaged Goods) Regulations 2006 apply to packages which are made up away from the customer in pre-determined constant quantities, by weight or volume, including most food and non-food items. The purpose of these controls is to ensure customer confidence in the stated quantity, whilst recognising and defining acceptable tolerances to the variation inherent in the packing process.

The 'average quantity' system controls the overall average quantity of a batch of packages and the proportion that fall below the stated nominal quantity through a set of defined packers' rules. It also lays down what checks you need to take, records to keep and how to mark packages. The controls apply to both packers and importers to the EU.

Package definition

A package is a product plus its wrapping when it is combined together without the purchaser being present, and the quantity cannot be altered without the wrapping being opened or changed. Specifically included in the above definition are knitting yarn and unwrapped bread.

'Outer containers' containing two or more 'packages' (at least one of which is a package to which these Regulations apply) which:

• were placed in the outer container without the purchaser being present
• can't be altered without the package being opened or undergoing a perceptible modification and
• the container is intended to be sold or would normally be regarded as appropriate for sale, as the outermost layer of packaging to a consumer are also caught by the requirements.

Excluded are very small and large items of less than 5g or 5ml, or more than 25kg or 25l. If you are in doubt about the product you are packing or importing, please contact us for specialist advice.

The three packers' rules

A batch of packages must, at the time of packing, comply with the following rules:

1. the actual contents of the packages must not be less, on average, than the nominal quantity
2. the proportion of packages which are short of the stated quantity by a defined amount (the 'tolerable negative error' or 'TNE') should be less than a specified level
3. no package should be short by more than twice the TNE

Checks

Packers and importers to the EU have a duty to carry out sufficiently rigorous checks to ensure that all of the three packers' rules are met. This means that you should establish a system that:

• controls the production process
• sets up effective sampling and checking plans
• uses appropriate equipment for checking
• trains staff
• keeps appropriate records

You have a duty to check the quantity of the packages, either:

• by checking every package on suitable equipment or
• by checking a statistical sample of the production on suitable equipment and keeping records of the results

Equipment

The equipment used to carry out the checks must be suitable for the use to which it is put. This means that it should have a reasonable degree of sensitivity to 0.2TNE for the package you are producing and be suitable for the environment in which it is used. If it is 'in use for trade' it has also to comply with its relevant regulations, depending on when it was first put into use. Please ask your local trading standards service for advice on specific equipment.

Actual Content of Packages

The actual content of a package is the total gross weight of the package less the weight of the packing. The weight of the packing without the contents is known as the 'Tare weight'. Tare weights may be constant for a production in which case the actual content of the packages is easy to determine by simple subtraction. However, where the Tare varies from pack to pack, an allowance must be made for this.

In summary, the best guide is to weigh 40 empty packages (or packing material) and determine the average and standard deviation of that group. If the standard deviation of the sample is less than 1/10 TNE for the package, it can be assumed to be constant. If it is over 1/10 TNE an allowance for the variation must be made in setting your target quantity for the production run. A regular check of the Tare variation should be made to see if it changes over time or with differing packing materials and the allowance adjusted accordingly. For more detail and advice you should contact your local trading standards service.

Records

If you are checking packages by statistical sampling, you must make records of the checks you have carried out. These records must show that you have complied with the three packers' rules. It is recommended that, as a minimum, you should record the product, the batch number, the date, the number of packs in the batch, the number checked and the results of the check. The records must be kept for 12 months from the time the packages leave your possession or the shelf life of the product, whichever is the earliest.

Markings

Marking needs to be easily legible and visible under normal conditions of presentation. This means taking into consideration use of colour and contrast. Packages must be marked with the following:

1. A statement of the nominal quantity. This statement must be in metric and the size of the marking is prescribed, e.g. for a 500g pack, the marking must be at least 4mm high.
2. Your name and address. Alternatively, you may give the name and address of the person who arranged for you to make up the packages.

You may mark the packs with the 'e' mark only on packages up to 10kg or 10L:



It must be at least 3mm high, indelible, easily legible and appear in the same field of vision as the statement of quantity. The 'e' mark acts as a metrological passport for goods sold throughout the European Economic Area. If you want to export goods with the 'e' mark, you may need to notify your local trading standards service first, so check with them before applying it.

Importers and average quantity

If you import goods from outside the EEA, you are responsible for ensuring that the packs comply with the three packers' rules and that they are marked correctly. However, you may obtain and keep suitable documents from the actual packer (before the packages leave your possession) that provides sufficient evidence to show that the packages comply with the packers' rules.
More detailed guidance on the application of the Regulations can be found on the Department for Business, Innovation and Skills website.

Tolerable Negative Error or 'TNE'

The following is a table of the TNE values that you should use when complying with the three packers' rules.

Nominal quantity (g or ml)	Tolerable Negative Error (TNE)
5 to 50	9% of nominal quantity
from 50 to 100	4.5g or ml
from 100 to 200	4.5% of nominal quantity
from 200 to 300	9g or ml
from 300 to 500	3% of nominal quantity
from 500 to 1,000	15g or ml
from 1,000 to 10,000	1.5% of nominal quantity
from 10,000 to 15,000	150g or ml
above 15,000	1% of nominal quantity

If you require further clarification or advice on this subject, please contact us using the details below.

Contact information

• email: ts.es@renfrewshire.gov.uk
• phone: 0141 840 3184 (select option 2)
• call in or write to us at:
  Renfrewshire Council
  Environmental Services
  Trading Standards
  Renfrewshire House
  Cotton Street
  Paisley
  PA1 1BR