Handbook 44, NTEP & Legal-for-Trade Compliance

"Legal-for-Trade" is not a brand name, a certification level, or a voluntary designation. It is a legal status that applies to any weighing device used in a commercial transaction where the measurement determines the basis of sale — what is bought, what is sold, what is paid for. If a weight printed by your scale determines a dollar amount, that scale is almost certainly required to be Legal-for-Trade under Michigan state law, regardless of industry.

In Michigan, the Division of Weights and Measures within the Michigan Department of Agriculture and Rural Development (MDARD) administers the legal framework governing commercial weighing devices. That framework is built on NIST Handbook 44 — the federal specification document that defines performance requirements, installation standards, and maintenance obligations for all commercial weighing and measuring devices.

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NIST Handbook 44: What It Is and What It Requires

The Foundational Standard for Commercial Weighing

NIST Handbook 44 ("Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices") is published by the National Institute of Standards and Technology and updated annually through the National Conference on Weights and Measures (NCWM). For commercial scales, it establishes performance tolerances by device class, installation requirements (foundation stability, environmental protection, approach conditions), zero-setting and automatic zero-tracking requirements, tare and net weight accuracy requirements, and the conditions under which a device must be removed from commercial service.

Tolerance Classes in Plain Language

Class III scales — the most common class for industrial and commercial applications — must perform within one scale interval of the true value at acceptance and within 1.5 scale intervals in maintenance (in-service) testing. Class IIIL scales, used for vehicle and axle-load scales, follow the same framework with capacity-adjusted tolerances. Understanding which class applies to your device and what the tolerance means in real units — pounds, tons — is essential for interpreting calibration results and knowing when a scale is legally out of tolerance.

NTEP: The National Type Evaluation Program

The National Type Evaluation Program (NTEP) evaluates whether a specific scale design meets Handbook 44 requirements. A scale with an NTEP Certificate of Conformance (CoC) has been tested by an NTEP-recognized laboratory and found to conform to applicable HB44 specifications for its design and accuracy class.

NTEP certification is required for any weighing device used in commerce in Michigan. The CoC number is visible on the scale nameplate. When a Weights and Measures inspector visits, one of the first things they check is whether your commercial scales carry valid NTEP CoC numbers. A scale that is accurate but lacks a valid NTEP CoC is not Legal-for-Trade — regardless of calibration status.

NTEP CoC confirms the design was approved. Calibration confirms the installed device is performing correctly. You need both for a scale to be Legal-for-Trade.

Michigan MDARD Inspections: What to Expect

MDARD inspectors visit commercial weighing operations on a schedule based on device type, commercial volume, and industry. High-volume applications — grain elevators, quarry truck scales, livestock markets — are typically inspected annually. Inspectors verify the NTEP CoC on the device nameplate, test zero-setting and automatic zero-tracking, apply test weights at multiple load points against maintenance tolerances, evaluate installation for code compliance, and review calibration certificates and service records.

A scale found outside maintenance tolerances is placed Out of Service with a condemning tag. Commercial use of a condemned scale violates Michigan law and can result in penalties. Cech provides emergency response for condemned scale situations — repair, recalibration, and coordination with MDARD for re-inspection.

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