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2002-08-28 Minimum amount of product weighed on a scale based on its graduation size
2002-08-28
PDF Format, 13 KB
Information
This note is to advise scale owners of the requirements governing the minimum amount of product that can be weighed on a scale based on its graduation size (increment) and intended use.
Issue:
Recent inspections have revealed instances where vehicle scales or other scales with large graduations are being used to weigh small amounts of product. Measurement Canada inspectors have therefore advised these scale owners of their obligation to comply with section 62 (Appendix A) of the Specifications Relating to Non-Automatic Weighing Devices (1998) and use a scale with a small enough graduation for accurate weight determination.
The problem with weighing a small amount of product over a scale with a large graduation, is that the scale cannot accurately determine the weight, which is automatically rounded to the nearest graduation. For example, if you were to weigh 95 kg of product valued at $1.00/kg using a scale with 10 kg graduations, the scale indicator would show either 90 kg or 100 kg, resulting in a an error of 5kg or $5.00. This rounding process can result in a loss for either the buyer or seller.
Section 62 of the Specifications:
Section 62 of the specifications was adopted in 1998, after consultation with scale manufacturers, end user groups and Measurement Canada. It outlines the minimum allowable net weighments for scales of varying graduation size, capacity and application based on the scales intended usage. It also outlines scale accuracy class requirements and ultimately requires that the correct scale be chosen for the intended weighing application.
The following are examples of how section 62 is applied:
• Refer to Appendix A, Item 7, Column III of the table. In the grain industry, the minimum allowable weight for a transaction using a scale with a capacity greater than 4000 kg, would be equivalent to two hundred times the verification scale interval “e” (graduation). For a scale with 5 kg graduations, this equates to 1000 kg (5 kg x 200). Essentially this means that within this industry the minimum weight that this type of scale should weigh would be 1000 kg in an effort to reduce the possibility of an inaccurate measurement due to the graduation size.
• For the scrap metal or recycling industry, the minimum net load for a transaction using a scale with a capacity greater than 4000 kg would fall under Item 8, Column III of the table. So if a scale has 2 kg graduations, the smallest quantity that could be weighed would be 200 kg.
Possible Solutions:
For existing electronic scales, there is the possibility of using a multi-interval or multi-range weight indicator configured for different graduation sizes. This would provide greater flexibility since the graduation size would be automatically selected depending on the amount of weight on the scale. However, prior to changing indicators, it is advisable to consult a reputable scale service company or manufacturer to determine if this is feasible for your particular scale.
Another possible solution would be to apply a flat rate for the purchase or sale of a quantity of product that is less than the minimum net load allowable for your scale. For example, some landfills accept half ton truck loads of garbage and apply a minimum charge for that type of vehicle (eg. $5/pickup).
If these solutions are not feasible, then the purchase of an appropriate scale may be the only option. Please be advised that Measurement Canada will enforce section 62 and we are requesting that you do your part to ensure equity in trade by using the appropriate scale for your weighing application.
To view legislation pertaining to scales or if you wish to discuss this matter at our annual Canadian Forum on Trade Measurement, please contact:
Eric Klawis
Senior Gravimetric Program Officer
4th Fl. 400 St. Mary Ave.
Winnipeg, Mb
R3C 4K5
ph: (204) 983-4722
fax: (204) 983-5511
email: klawis.eric@ic.gc.ca
Appendix A: Excerpt of section 62 of the Specifications Relating to Non-Automatic Weighing Devices (1998) (PDF Format)
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