This site will look much better in a browser that supports web standards, but it is accessible to any browser or Internet device.
ToolsRelated topicsResourcesAccuracy Requirements for Net Quantity DeclarationsConsumer Packaging and Labelling Act and RegulationsOctober 1999
Table of ContentsAccuracy Requirement PrinciplesAppendix IAppendix IIAppendix IIIAppendix IV
Appendix V
Appendix VIAccuracy Requirements for Net Quantity DeclarationsThe Fair Business Practices Branch, Competition Bureau, Industry Canada, administers the Consumer Packaging and Labelling Act and Regulations which establish the accuracy requirements for net quantity declarations for most prepacked consumer products. Amendments to the Regulations, in effect since December 20, 1989, define the procedure for verifying the accuracy of net quantity declarations.Briefly, the requirements specify that:
These requirements benefit both consumers and packers. Consumers are assured that over the long term, they will receive at least the quantity paid for. Packers benefit from having reasonable tolerances within which to operate and some assurance that these requirements meet most international standards for accuracy. BackgroundIn developing the regulations, the primary source document was the Organisation Internationale de Métrologie Légale (OIML) recommendation "Net Contents in Packages". This document was modified to allow for differences of application within Canada as the OIML recommendation is designed to apply only to prepackaged commodities that are to be traded internationally. The Consumer Packaging and Labelling Regulations, however, apply solely to commodities intended for sale in Canada. In the OIML document the inspection methods, compliance criteria and sampling procedures, commonly known as the Average System, were developed through referencing existing standards that had already received widespread international acceptance. These standards were developed primarily by an international standards writing organization and others such as U.S. Military Specifications (MILSPEC). The ISO standards from which test methods for the Canadian regulations were derived are: ISO 2854 Statistical interpretation of data - Techniques of estimation and tests relating to means and variances. ISO 2859 Sampling procedures and tables for inspection by attributes. Copies of these standards may be purchased through:
Accuracy Requirement PrinciplesThere are three principles that must be met to comply with the accuracy requirements of the Consumer Packaging and Labelling Act and Regulations: 1. The declared quantity on a package should accurately reflect the quantity being supplied, so the average net contents of the packages in a lot may not be less than the declared quantity.Knowing that production techniques are neither perfect nor ideal, it is sufficient to ensure that on average the packages contain the declared quantity. The average requirement provides protection to consumers who purchase more than one package of a particular product. Generally, a deficiently filled package will be compensated for by an overfilled one. 2. The control over production should be such that the individual packages are within allowable tolerances. No more than 2.5% of the lot may have a negative error larger than the tolerance.A lot will not meet the requirements of the Consumer Packaging and Labelling Act and Regulations if in a sample the number of units containing less than the declared net quantity, by more than the prescribed tolerance, exceeds the number permitted by the Regulations. 3. The number of packages which may have excessive negative errors is limited. Not more than one package may contain less than twice the permitted tolerance.In recognition of an occasional mishap in the packing process, the presence of one significantly defective package in the sample will not jeopardize the results of the inspection. The pass/fail criteria are related to an Acceptable Quality Level (AQL) rather than the performance of individual packages. Appendix I to Appendix V highlight excerpts from the Consumer Packaging and Labelling Act and Regulations relating to net quantity. Explanatory notes are provided under the "Guide" heading. This document is not provided to instruct on the precise method whereby a packer may comply with the regulatory requirements, but only to advise on what those requirements are. Appendix VI is an example of a lot inspection to assist in understanding how compliance is assessed. For additional information on the application and interpretation of the requirements of the Consumer Packaging and Labelling Act and the Consumer Packaging and Labelling Regulations, please contact the Competition Bureau:
For information on industrial, commercial and institutional packages, which are subject to the Weights and Measures Act, contact Measurement Canada.
Appendix IRelevant Excerpts from Section 7 of the Consumer Packaging and Labelling ActSection 7 of the Consumer Packaging and Labelling Act states:
Appendix IIRelevant Excerpts from Section 38 of the Consumer Packaging and Labelling RegulationsSection 38 of the Consumer Packaging and Labelling Regulations states:
GUIDE: The tolerances correspond to those accepted internationally. Appendix IIIRelevant Excerpts from Section 39 of the Consumer Packaging and Labelling RegulationsSection 39 of the Consumer Packaging and Labelling Regulations states: Examination
GUIDE: Section 39, in its separate paragraphs, defines how a lot is to be inspected. This subsection makes it mandatory to test a "lot" of products by drawing a sample and applying the tests of the subsequent subsections to the sample to determine if the lot is acceptable.
GUIDE: Minimum sample sizes are set out in Schedule II. All testing will be carried out on the sample to determine compliance of the lot. Inspectors have the authority, and may use larger samples if it is felt necessary, but additional sampling will rarely be required.
GUIDE: In some cases it will be necessary to destroy the product in order to verify the contents of a package. This section restricts the number of packages that will be destroyed.
GUIDE: On average, a lot must contain the declared quantity. The formula referred to uses the sample mean to which a weighting factor is applied to determine if the lot average meets this requirement. There is no tolerance on the weighted lot average, so the value calculated by the formula must be equal to or greater than the declared quantity.
GUIDE: Some packages are allowed to be below the tolerance, but the total number allowed is dependant on the sample size. The number of units shown in the table indicates when a lot will fail.
GUIDE: Only one package in the sample can be deficient by more than twice the tolerance, regardless of lot size. NOTE: The above tests are designed to give an overall picture of the lot. The requirements of the three subsections must all be met in order for the lot to pass. Appendix IVSchedule I of the Consumer Packaging and Labelling RegulationsSCHEDULE I(Section 38)PART ITolerances for net quantities declared in metric units of mass for catch weight products
GUIDE: The tables in Schedule I, set out the tolerances for individual packages. The table that is referenced is dependant upon the commodity and the net quantity declared on its label. PART IITolerances for net quantities declared in canadian units of mass or weight for catch weight products
PART IIITolerances for net quantities declared in metric units of mass or volume for prepackaged products other than catch weight products
PART IVTolerances for net quantities declared in canadian units of mass or weight for prepackaged products other than catch weight products
PART VTolerances for net quantities declared in canadian units of volume for prepackaged products other than catch weight products
PART VITolerances for net quantities of solid prepackaged products declared in metric units of volume
PART VIITolerances for net quantities of solid prepackaged products declared in canadian units of volume
PART VIIITolerances for net quantities of prepackaged products declared in metric units of length
PART IXTolerances for net quantities of prepackaged products declared in canadian units of length
PART XTolerances for net quantities of prepackaged products declared in metric units of area
PART XITolerances for net quantities of prepackaged products declared in canadian units of area
PART XIITolerances for net quantities of prepackaged products declared by number
Appendix VSchedule II of the Consumer Packaging and Labelling RegulationsSCHEDULE II(Section 39)PART ISamples
GUIDE: Schedule II provides the statistical basis for determining compliance of lots against the requirements of section 39. Part I gives minimum sample sizes, Part II provides the necessary formulas for calculating the lot average from the sample mean, and Part III lists the values for "t" which are the weighting factors that are used in Part II. PART IIFORMULA FOR DETERMINING THE WEIGHTED AVERAGE QUANTITY OF THE UNITS IN A SAMPLEFor the purposes of paragraph 39(4)(a), the formula for adjusting the sample mean to determine the weighted average quantity of the units in the sample is as follows:In the formula above:
t is the value determined in accordance with Part III for the selected sample size n is the number of units in the sample s is the standard deviation of the sample, calculated as follows:
GUIDE: These formulas provide a statistical method that eliminates any bias which may be introduced by the selection of the sample. The mean (average) of the sample is adjusted by a factor that is related to the demonstrated packaging accuracy (standard deviation). Relating the sample mean to the weighted lot average in this way provides a confidence level of 99.5% that good lots will not be failed in error. PART III
GUIDE: Because the "t" values are used to calculate the lot average from the sample mean, this weighting factor is not required in those cases where every package in the lot is tested. Therefore, as the footnote above shows, the value of "t" is equal to zero for those cases. PART IVMinimum number of units for the purposes of
|
Item | Column I | Column II |
---|---|---|
Sample Size | Minimum Number of Units*** | |
1. | from 2 to 8 | 1 |
2. | from 9 to 20 | 2 |
3. | from 21 to 32 | 3 |
4. | from 33 to 50 | 4 |
5. | from 51 to 65 | 5 |
6. | from 66 to 80 | 6 |
7 | from 81 to 102 | 7 |
8 | from 103 to 125 | 8 |
GUIDE:
For any sample size listed above, the number in Column II represents the minimum number of defective packages in the sample which would fail the lot. If the total number of defective packages equals or exceeds the number in Column II, the lot fails regardless of any other test results.
The following example illustrates how an inspection is conducted for a lot of prepackaged products to determine if it meets the requirements under the Consumer Packaging and Labelling Act and Regulations. It is important to understand that this is the required procedure for the Fair Business Practices Branch when conducting inspections, however, it is not an appropriate method for a packer to use for ensuring compliance.
Assuming a lot of 3000 packages, each labelled as containing 50 grams:
The required number of packages that form the sample is randomly selected.
See notes on Section 39(2) and refer to the table in Schedule II, Part I.
A sample of 32 units is, therefore, required for a lot size of 3000 units.
The tolerance is determined for each package labelled as containing 50 grams.
See notes on Section 38(2) and refer to table in Schedule I, Part III.
For a net quantity declaration of 50 grams, the tolerance is 9%, or 4.5 grams.
Each package in the sample is weighed. The following net weights are examples:
1) 49.7 g | 7) 49.9 g | 13) 50.1 g | 18) 50.0 g | 23) 49.6 g | 28) 49.9 g |
2) 50.2 g | 8) 50.3 g | 14) 40.2 g | 19) 50.1 g | 24) 50.5 g | 29) 49.9 g |
3) 49.9 g | 9) 50.2 g | 15) 50.0 g | 20) 49.8 g | 25) 49.7 g | 30) 49.5 g |
4) 45.4 g | 10) 50.0 g | 16) 50.1 g | 21) 49.9 g | 26) 50.1 g | 31) 50.2 g |
5) 50.0 g | 11) 49.8 g | 17) 49.8 g | 22) 50.1. g | 27) 51.5 g | 32) 49.9 g |
6) 50.1 g | 12) 50.0 g |
The number of packages which are deficient by more than the allowable tolerance of 9% (4.5 grams) are counted, i.e., those packages weighing less than 45.5 grams. Two such deficient packages are found: 45.4 g and 40.2 g (items # 4 and #14).
See notes on section 39(4)(b) and refer to the table in Schedule II, Part IV.
From this table you will note that three or more deficient units will result in lot failure. Therefore in this example, the criteria stated in Section 39(4)(b) has been met as the lot sample contains two deficient units.
The number of packages which are deficient by more than twice the allowable tolerance are counted, i.e., those packages weighing less than 41 grams (4.5 grams X 2=9 grams).
One such deficient package is found: 40.2 g (item # 14)
See notes on Section 39(4)(c) which allows only one package to be deficient by more than twice the tolerance.
Therefore, in this example, the criteria stated in Section 39(4)(c) has also been met.
The weighted average of the sample is determined.
See notes on Section 39(4)(a) and refer to Schedule II, Parts II and III.
a) The average weight or mean () of the sample is calculated by adding the total weight of the sample packages and dividing by 32 (the number of units in the sample).=49.58 g
b) The Standard Deviation (s) is calculated. s=1.926 g |
c) For a sample size of 32 the value for is obtained from Schedule II, Part III, column III. =0.485
d) The weighted average is calculated by using the formula
=49.58 g + (1.926 g x 0.485)
=50.51 grams
As the weighted average is greater than the declared quantity of 50 g, the criterium prescribed in 39(4)(a) of the Regulations has been met.
This example shows that the requirements of paragraphs 39(4)(a), (b) and (c) have all been met, therefore, the lot of 3000 packages is acceptable.
NOTES:
*The value of may, instead of being calculated in accordance with this Part, be determined using the applicable value set out in column III of the table to Part III.
**Where all units in a lot are selected to constitute a sample, zero shall be used as the value of t and .
*** Minimum number of units in the sample that results in the lot not meeting the requirements of the Act and these Regulations respecting the declaration of net quantity.