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M-12 (rev. 1) Temperature Rating of Electronic Scales - Automatic Weighing Devices

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Date: 1998-03-02
Bulletin: M-12-E (rev. 1)
Category: Mass
Supersedes: M-12-E
Document(s): SGM 1-19, SGM 3-11.1

1.    Weights and Measures Specifications SGM-1 and SGM-3 require that an electronic automatic weighing device meet or exceed the performance criteria of the Weights and Measures Regulations when tested under ambient temperature conditions from -10ºC to 40ºC.

2.    This requirement is inconsistent with the requirements of the United States, found in Handbook 44, and OIML International Recommendation R 76-1.

3.    The Specifications Relating to Non-Automatic Weighing Devices do not restrict the temperature range to -10ºC to 40ºC.

4.    In light of the above, the following policy, which is consistent with US and OIML requirements, has been developed and takes effect immediately (effective since May 1, 1994).

5.    Upon filing an application for approval, the applicant may or may not expressly specify the minimum and maximum operating temperatures for which an approval is sought.

6.    If the applicant does not specify the minimum and maximum temperatures, or if the device is marked with a minimum temperature of -10ºC and a maximum temperature of 40ºC, then the device will be tested over the regular temperature range of -10ºC to 40ºC.

7.    A device described in paragraph 6 may be used beyond the minimum and maximum temperatures of -10ºC and 40ºC, provided that it continues to perform within allowable limits of error as specified in the Weights and Measures Regulations and Specifications SGM 1 and SGM 3.

8.    If the applicant requests that the device be tested and approved for a minimum temperature higher than -10ºC or a maximum temperature lower than 40ºC, then the device shall bear markings specifying the minimum and maximum temperatures and shall not be used beyond those temperatures.

9.    Under no conditions will the difference between the minimum and maximum temperatures be less than:

9.1    5ºC for devices with more than 50 000 increments of registration;

9.2    15ºC for devices used to weigh precious metals and other commodities of comparable value; and

9.3    30ºC for devices used to weigh commodities other than precious metals or commodities of comparable value.

10.    If an applicant expressly requests a minimum temperature lower than -10ºC or a maximum temperature higher than 40ºC, the device must be tested over the expanded temperature range and marked accordingly, provided that the Measurement Canada laboratories are equipped to test this expanded range.

11.    A device approved for a minimum temperature lower than -10ºC or a maximum temperature higher than 40ºC must perform within the allowable limits of error over the range of approved temperatures. The device may be used beyond the approved minimum and maximum temperatures provided that it continues to perform within allowable limits of error as specified in the Weights and Measures Regulations and Specifications SGM 1 and SGM 3.

12.    Revision: The purpose of this revision is to:

1. render the bulletin applicable to automatic weighing devices;

2. add section 3; and

3. make minor changes to the text.

13.    For additional information, please contact:

Jeff Watters
Program Officer, Mass and Commodity Measurement
Program Development Directorate
Measurement Canada