US Legal Metrology — Handbook 44 Tolerances, Tests, Standards, Handbook 133 Net Contents and NTEP Certificates (Odoo 19 Community)

US Legal Metrology — full edition

Installs on top of the free edition dyo_metrologie_us_lite — device inventory, jurisdictions, inspections, printable report — without asking for anything again, and adds everything that requires a calculation, a regulatory table or an external service.

Also searched as: NIST Handbook 44 tolerances Odoo, maintenance and acceptance tolerance, scale test record, Handbook 133 net content inspection, MAV maximum allowable variation, Category A sampling plan, NTEP certificate of conformance database, field standard traceability, weights and measures inspection plan.

The two tolerances, and the thirty-day window. Handbook 44 distinguishes acceptance tolerance — a new device, one returned to service after rejection, an overhauled device, or one undergoing type evaluation — from maintenance tolerance, for a device in service. The distinction is not a matter of preference: paragraph G-T.1 of its General Code lists the five circumstances and attaches a thirty-day window to them. The module therefore makes the circumstance an input and the tolerance a calculation: you describe the situation, the tolerance follows, and the module states in plain language why it chose that one. After thirty days it automatically switches to maintenance tolerance and says so — applying acceptance tolerance beyond that point would reject a device that Handbook 44 considers compliant.

The one-half ratio is NOT a general rule, and this is the mistake to avoid. Appendix A § 2.1 describes it only as a practice — “usually one-half of”. It is prescriptive only in certain codes: 2.20 § T.N.3.2, 2.22 § T.3.1. Other codes have a single value for both tolerances. Each tolerance set therefore carries its own acceptance rule, with four values, including “not specified” — and an unspecified tolerance is never guessed.

Table 6 of code 2.20, transcribed line by line, with its extension rule for class III L (“Add 1 e for each additional 500 e or fraction thereof”) and the rule for intermediate values in § G-T.4, which requires the lower line. It is the only table shipped, and that is deliberate: other codes are entered manually, with their citation.

Tests and their readings. Applied load, indication, error, load in verification scale divisions, tolerance read from the table, finding. Three possible outcomes per reading — within tolerance, out of tolerance, tolerance unknown — and the third matters as much as the other two.

Standards and the one-third rule. Appendix A § 3.2: “its combined error and uncertainty must be less than one-third of the applicable device tolerance”. The module checks it on every test, walks the traceability chain link by link, and flags links with no certificate, no laboratory, or an expired calibration.

The Handbook 133 net content test, carried out step by step: Category A or Category B sampling plan transcribed in full, MAV read from Table 2-5 (pound and gram series, complete), moisture allowance added to the MAV as required by § 1.2.6.1, sample standard deviation with an n − 1 denominator, sample error limit, and both requirements tested simultaneously. Each step is written out so that the calculation can be redone by hand — and challenged.

NTEP certificates, and what “traced” means. The uniform regulation in Handbook 130 makes it a conjunction: same type as the certificate and manufactured while that certificate was active. The module calculates it, and answers “undetermined” as long as one half is missing.

The verification plan and the alert. An alert warns the day before; a plan prepares the quarter. The plan only includes what has a due date, and counts separately the devices that could not be included, with the reason: inventing a date for them would include them wrongly.

Regulatory history. The module records whatever shifts a date or a tolerance — a changed state inspection interval, a newly adopted handbook edition, a reclassified device — along with the number of devices affected.

The NCWM's NTEP registry: the API AND its workaround. The NCWM publishes no documented API. The service its own website calls does respond, with no account or key, but it is undocumented and the site's terms of use set a restriction the user must read: “The information and materials contained on this site may not be used for any commercial purpose.” The source is therefore shipped inactive, with no URL and in offline mode, with this quotation in plain view, and the module works fully without it: certificates are entered by hand, and that is the default path. The source plugs into the dyo_connexions_base chain — timestamped cache, queue, log, degradation that does not lie — of which this module does not write a second one.