S&T Committee

Specifications and Tolerances Committee

The Specifications and Tolerances (S&T) Committee is dedicated to issues related to the design, testing, tolerances and user requirements for commercial weighing and measuring devices.  This broad scope includes scales, meters, measure containers, grain analyzers, taxi meters, timing devices, length measuring devices and more.  The standards adopted through the S&T Committee are published in Handbook 44 Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices .

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   Task Groups

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NCWM received a proposal in 2017 that would add security measures to Handbook 44 to protect against the installation of credit card skimmers in commercial weighing and measuring devices.  Increasingly, these skimmers are installed illegally to steal consumers’ credit card data.

The proposal would require the device manufacturers or end-users of weighing and measuring devices to restrict unauthorized access to components previously considered to be non-metrological.  During Open Hearings of the 2017 NCWM Interim Meeting, the Specifications and Tolerances Committee was asked to consider whether the proposals were outside the scope of legal metrology and therefore not within the scope of Handbook 44

The Specifications and Tolerances Committee recognized the significance of this question, but also recognized the role of the weights and measures official to protect buyers and sellers in commercial transactions.  At the committee’s request, a special Credit Card Skimmer Task Group was formed in 2018 to address the issue.

The charge of the task group is to determine if these types of security standards are appropriate in Handbook 44.

If yes, the next steps will be to:

  1. Consider whether the proposal should be a design specification for the device manufacturer and a security requirement for the end user.
  2. Develop and submit recommendations to the S&T Committee for further consideration by NCWM.

Task group members include Active members representing each of the 4 regional weights and measures associations and Associate members representing equipment manufacturers and trade groups.

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Based on the majority of the comments received during open hearings at the 2019 NCWM Interim Meeting, related to the items contained in Block 1, Block 2, and the items GEN-3, LPG-3, MFM-5, and HGM-6, there is a desire to uniformly define what is considered a “standard” for tests in the field and to establish criteria for the standards not already addressed through the NIST 105 Series of handbooks.

 The S&T Committee requested a Field Standards Task Group be formed to complete the following:

  •  Find, examine, and develop a definition(s) for standards used in field testing
  • Make appropriate changes in Handbook 44 which may include:
    • replace the definition in Appendix D for transfer standard, if appropriate
    • replace the term “master meter” in the definition of “master meter test method” if appropriate
    • replace references to transfer standards and/or other uses of terms in the handbook for standards used in field testing, with the new term(s) if appropriate
  • Work with the appropriate stakeholders to develop criteria to determine what is a suitable standard, which may include:
    • adding a statement to Section 3.2 in Handbook 44, Fundamental Considerations, to address another option for standard accuracy during testing, elaborate on traceability and how it is achieved, and language concerning regulatory responsibility similar to what is included in Handbook 130.

Goal for completion is within two (2) years, July 2021.

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The task group will submit its recommendations to the Specifications and Tolerances Committeee for consideration by the NCWM membership.

The mission of the WIM TG is to:

  1. Propose changes to Handbook 44, Section 2.20 Scales and, if necessary, Appendix D to allow for the use of Class IIIL WIM devices in commercial applications.
  2. The WIM Task Group may decide to request or review data from a manufacturer of a Class IIIL WIM device.  Data considered by the WIM Task Group will be gathered based on the following criteria as specified by the S&T Committee:

i. Witnesses present during data collection procedures - Local weights and measures officials, as well as NTEP and NIST representatives, should be present during testing of the reference scale and during the data collection process.

ii. Reference Scale - Class IIIL static vehicle scales tested in acceptance tolerance, in accordance with Handbook 44 test procedures, as directed by local weights and measures officials as well as NIST and NTEP representatives.

iii. Field Standards - Field standards used to test the Class IIIL static vehicle scale should meet the calibration requirements specified by local weights and measures officials.

iv. Reference Standards - The suitablility of the vehicle(s) to be used for data collection purposes will be determined by local weights and measures officials as well as NIST and NTEP representatives.

v. Data Collection - The procedure to collect data will be determined by local weights and measures officials as well as NIST and NTEP representatives.