NTEP is the American counterpart to an OIML pattern approval. If equipment is going to be used for trade in the United States, most states will ask for it. This article covers who issues the certificate, what it is checked against, and what the wording on the certificate actually commits the manufacturer to.
Certificate of Conformance
The National Conference on Weights and Measures issues an NTEP Certificate of Conformance after a device evaluation is completed successfully. It states that the device described in the certificate is capable of meeting the applicable requirements of NIST Handbook 44.
Handbook 44 is the rulebook: specifications, tolerances and other technical requirements for weighing and measuring devices. An NTEP certificate is a statement about a type of device, made before it reaches commerce — not a calibration of the individual unit on your floor.
Who NCWM is, and why it exists
NCWM is a non-profit association bringing together state and local weights-and-measures officials, federal agencies, manufacturers, retailers and consumers. It has been developing national measurement standards since 1905. The reason it was needed is a story about fragmentation.
Through the 19th century. The US Constitution left each state free to regulate weights and measures inside its own borders. Every state wrote and enforced its own rules. The inconsistency held back economic growth and made interstate trade less honest.
1905. The National Bureau of Standards called the states to a meeting about the missing uniform standards — and, in many cases, the missing regulatory oversight altogether. The delegates agreed to meet again the following year, which is how NCWM began.
1915. The first NCWM model standards were published, to be used as tolerances and specifications for weighing and measuring devices.
1984. The National Type Evaluation Program was established. Its administrative and technical policies and evaluation checklists are published in NCWM Publication 14.
Today. More than a century on, NCWM keeps national standards abreast of developing technology and marketing practice, still with regulators, industry and federal agencies all at the table.
Where the rules are written down
Standards adopted by NCWM are published by the National Institute of Standards and Technology in three handbooks:
| Handbook | Covers |
| NIST 44 | Specifications, tolerances and other technical requirements for weighing and measuring devices — the document an NTEP certificate is measured against |
| NIST 130 | Uniform laws and regulations |
| NIST 133 | Checking the net contents of packaged goods |
NIST also supplies technical advisers to NCWM working groups and committees, which is what keeps the rules consistent across the federation and aligned with international standards. Full texts are published at nist.gov.
Two definitions people get wrong
What does the certificate actually promise?
That the device described in it is capable of meeting the applicable Handbook 44 requirements. It gives manufacturers a level competitive field and assures the end user that the equipment being bought is fit for the job. It does not replace the periodic verification of the installed instrument.
What counts as “commercial use”?
Any device used to sell, buy, exchange, transfer custody, or establish a charge for a service or a rental on the basis of measurement. If money changes hands based on the reading, the device is in commercial use — and most states then require NTEP certification.
Standards note
KALA Technical Notes
NTEP and OIML are separate systems with separate certificates, and holding one does not automatically satisfy the other. If your equipment has to be accepted in more than one market, tell us where it will be installed and we will confirm which approvals the load cells and indicator need to carry.
● Load cells and weight indicators with recognised pattern approvals for trade use.