Look closely at a deli scale, a fuel dispenser or a weighbridge indicator and you will usually find a small label or stamp with nine characters on it. People search for it as the NMI sticker. For a verifier, it is the mark that says this instrument was tested, by whom and when.
Here is how the mark is built, where it goes and how it differs from a seal, based on National Measurement Institute (NMI) guidance for servicing licensees. Check NMI’s current guidance for anything specific to your licence.
The nine characters
A verification mark has nine letters and numbers in three parts:
1. Servicing licensee mark: three uppercase letters that identify the licensee. 2. Verifier code: four numbers, the last four digits of the verifier’s registration number. VR-00234 becomes 0234. 3. Month and year code: one uppercase letter for the month and one digit for the year the instrument was verified.
NMI’s own example is ABC0234K2: licensee ABC, verifier VR-00234, verified in November 2022.
Month and year codes
Months run from A to L: A January, B February, C March, D April, E May, F June, G July, H August, I September, J October, K November, L December.
The year code is the last digit of the year: 5 for 2025, 6 for 2026, 7 for 2027. An instrument verified in October 2026 by verifier VR-00234 for licensee ABC carries ABC0234J6.
Because the year is a single digit, the same code comes round every ten years. The mark tells you who verified the instrument and in which month; the instrument’s records tell you the rest.
Where the mark goes
NMI says the mark can go on a label fixed to the instrument, on a stamp plug secured to it, or on the instrument’s surface. Put it where a servicing licensee or a trade measurement inspector can easily reach it, where it is unlikely to be damaged and will stay clean and legible, and, if possible, where customers can see it. Each instrument carries one verification mark.
Marks must be permanent. NMI suggests a stamping tool on labels. If you use a pen or permanent marker, cover the label with clear contact so cleaning does not wipe the mark off. Labels must be attached to the instrument permanently, not folded over or stuck on a case or a wall next to it.
Stamp plugs may not have room for all nine characters. NMI asks licensees in that position to contact it about how to comply.
NMI supplies adhesive verification labels to servicing licensees at no cost. The licensee’s nominated contact person asks for them, giving the licence number, the quantity and the business address.
Marks and seals are different things
Many instruments must be sealed after verification; the certificate of approval says whether. Seals must be tamper evident. They can be lead plugs, sealing wire with a crimp seal, an adhesive label or foil, or an electronic access counter.
- A seal carries only the servicing licensee mark, the three letters.
- NMI-supplied verification labels must not be used as seals, and a seal should not be mistaken for a verification mark.
- If you break one sealing point to make a repair, only that point needs resealing with your licensee mark.
Advertising stickers are fine, as long as they can’t be confused with a verification mark. NMI suggests adding “this is not a verification mark” to them.
The mark on the form
On Form 6 and Form 6A, the verifier’s mark field takes seven characters, the licensee mark and verifier code, such as ABC0234, without the month and year code. The verification date has its own column. NMI’s form rules ask for the licensee and verifier parts only; see Form 6 and 6A mistakes for the rest.
When an instrument is re-verified or fails
When an instrument is re-verified after adjustment or repair, NMI says to remove or obliterate the previous verification mark. When an instrument is tested and not verified, the regulations require any verification mark on it to be obliterated. Our guide to re-verifying a repaired scale covers which repairs call for a new verification.
How OpsChase builds the mark
In OpsChase for trade measurement verifiers, the mark is built for you from the licensee mark, the verifier’s code and the test date’s month-and-year code, so nobody at the end of a long run stamps last month’s letter. Pass, fail or non-verification is recorded with a reason, and the form export uses the seven-character version automatically.
Each verifier’s registration number, statement of attainment and the licence subclasses they are competent for sit on their profile, so a job can only be assigned to someone qualified for that instrument. Every mark, test and form is kept against the instrument, and customers get a branded verification certificate and a reminder when their next check is due. OpsChase is independent software, and it is not made or endorsed by NMI.
Where to start
Add your licensee mark and each verifier’s registration number, then bring across your customer sites and instruments. From the next job, every mark and every form comes from the same record.
Read about the servicing licensee behind each mark, check pricing or book a demo.