S&T Committee

Specifications and Tolerances Committee

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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 .


Committee Handbook  |  View Members

   Task Groups

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This task group submits its recommendations to the S&T Committee for consideration by the NCWM membership.

In 2017, NCWM received a proposal to 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 at the 2017 NCWM Interim Meeting, the Specifications and Tolerances (S&T) 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 S&T Committee understood the significance of this question, but also recognized the role of the weights and measures official to protect buyers and sellers in commercial transactions.  In 2018, at the Committee’s request, the Credit Card Skimmer Task Group was formed to address the issue.

Mission:  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 NCWM members representing each of the 4 regional weights and measures associations and associate NCWM members representing equipment manufacturers and trade groups.

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This task group submits its recommendations to the S&T Committee for consideration by the NCWM membership.

Due to a 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.

Mission:

  • 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 Handbook 44, Section 3.2., 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:  Completion by July 2021.

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This task group submits its recommendations to the S&T Committee for consideration by the NCWM membership.

Mission:

  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 task group may decide to request or review data from a manufacturer of a Class IIIL WIM device.  Data considered by the 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 NTEP and NIST 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 NTEP and NIST representatives.

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

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This task group submits its recommendations to the S&T Committee for consideration by the NCWM membership.

Mission:  Review Handbook 44, Section 2.20. Scales and relevant portions of OIML R76, using the items included in Block 2 as a reference, and recommend changes as necessary to:

  1. Clarify how error is determined in relation to the verification scale division (e) and the scale division (d).
  2. Clarify which is the proper reference, the verification scale division (e) or the scale division (d) throughout this section.
  3. Ensure proper selection of a scale in reference to the verification scale division (e) and the scale division (d).
  4. Clarify the relationship between the verification scale division (e) or the scale division (d).

The group should include: the submitter, Ross Andersen (retired), a regulator from each region, representatives from the scale industry, technical advisors from NIST and NTEP, and other interested stakeholders.

Goal:  Return the task group recommendations to the S&T Committee by November 15, 2023.

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Mission:  To review (possibly recommend) changes to the tolerances that appply to milk meters, which may include milk measuring systems in:

  • Section 3.31. Vehicle Tank Meters
  • Section 3.35. Milk Meters
  • Section 3.37. Mass Flow Meters
  • Section 4.42. Farm Milk Tanks

The task group will consider the tolerances proposed by the S&T Committee Item VTM-20.2. and the tolerances in OIML R 117-2 in their discussions.

The group should include a regulator from each region, technical advisors from NIST and NTEP, the submitters from POUL TARP A/S and Piper Systems Limited and may include other meter manufacturers, industry stakeholders (producers and processors), and other interested parties.

Goal:  Return task group recommendations to the S&T Committee by November 15, 2023.