May 26, 2015

4 Min Read
Package Content Compliance
Tom Dorward Mettler-Toledo Hi-Speed

Product recalls or halts in production are the nightmare of every production manager. The loss in output, additional rework costs, and damage to your company's reputation can have long-lasting effects. Understanding packaging standards and methods of ensuring compliance can provide piece of mind to any packaging operation.

In the U.S., the procedural guide for compliance testing of net content statements on packaged goods is contained within the National Institute of Standards and Technology Handbook 133 (NIST HB133). The procedures in NIST HB133 are used to verify the net quantity of contents of packages offered for sale, or sold by weight, measure (including volume, and dimensions), or count at any location in the point-of-pack, distribution, or point-of-sale. Products tested by Weights and Measures are typically done so without notice and are based on:

1. Marketplace surveys of a specific product, such as a jurisdiction-wide survey of all breads
2. Surveys based on sales volumes
3. Audit testing to cover a large variety of products in an area or location
4. Follow-up tests to ensure problems associated with prior tests have been corrected
5. Testing requested in response to a complaint or allegation of non-compliance

While NIST HB133 comprises of almost 200 pages of guidance, tables, and procedures, the two fundamental rules which must always be followed and complied with for packaging are:

1. Average Requirement: The average content weight of “Good” packages must be equal to or greater than the stated Label Weight on the package.¹
2. Maximum Allowable: No individual package can have a content weight that differs from the label weight by a value greater than the Maximum Allowable Variation (MAV) as defined in NIST HB1331.

For most, the "Average Requirement" is an understandable concept: on average, the customer should get the amount of product that they are told that they are getting. However, the Maximum Allowable Variation or MAV and its application to individual package weights may be less well known.

The MAV as defined by NIST is “a deficiency in the weight, measure, or count of an individual package beyond which the deficiency is considered to be an "unreasonable error".1 A series of tables located in Appendix “A” of NIST H133 are used to determine the MAV for a package weight which range from 10% of the label weight for weights less than 36 g to 2% of the label weight for packages over 24.67 kg. Applying the table to a 25-kg package yields a .5 kg MAV, meaning the package could weigh 24.5 kg and still meet the MAV requirement. While this may sound like the regulation makes allowance for under filled packages, remember that the average weight of the lot still must be equal to or greater than the label weight. MAV only makes allowance for the occasional process error.

This basic knowledge of NIST HB 133 may not make you an expert, but hopefully you feel better prepared to evaluate your packaging line performance and its compliance to the standard. A production process that runs without interruption is not guaranteed to be running optimally and economically. Evaluation of your line is only the first step in assuring compliance, but it is an important one that can lead to more opportunities of improvement.

Investing in an inline checkweigher or static scale is an example of an improvement that can not only assure compliance, but provide a cost savings. Modern checkweighers deliver a high degree of confidence that the net contents of packages which are being shipped to the consumer comply with local Weights and Measures regulations due to their accuracy. This accuracy translates into a cost savings by ensuring packages are not over-filled, thereby reducing product giveaway. The most accurate checkweighers will provide you the greatest opportunity to maximize your return, simultaneously ensuring you are in compliance with governmental regulations.

Concerns about weight compliance don't have to be a part of your business. Understanding the standards and partnering with the proper scale supplier can yield surprising results.

1National Institute of Standards and Technology (NIST) Handbook 133: Checking the Net Contents of Packaged Goods (2015 edition).

Tom Dorward has been with Mettler-Toledo Hi-Speed for more than 31 years. His current role is product manager, where he has responsibilities for Weights and Measures compliance.

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