Two Documents Called 3.1: the Fastener’s and the Material’s

The conclusion first. The number 3.1 belongs to two sets of documents at once: the material’s and the fastener’s. ISO 16228:2017 §4.1 hands the material documents 2.1, 2.2, 3.1 and 3.2 over to ISO 10474 or other relevant technical specifications — the example the standard itself gives is EN 10204 — and governs only F2.1, F2.2, F3.1 and F3.2.

§4.3.4 then says the results in a fastener F3.1 shall be taken from raw material certificates (3.1 or 3.2), fastener in-process control and/or final inspection. So the two are not synonyms and neither replaces the other. One is the other’s input.

⚠️⚠️ And the last sentence of §5.4 closes the most common shortcut outright: transferring of non-specific test/inspection results from F2.2 (or from 2.2 for material) into an F3.1 inspection document is not allowed.

Why “3.1 required” is not a requirement

This site already said, in what belongs on an enquiry, that writing "3.1" alone is incomplete because more than one standard uses that number. The reason given there was a name collision. Having read the clauses, the reason is more specific than that.

A material 3.1 is about a heat of steel: composition, mechanical properties, which melt it came from. A fastener F3.1 is about a lot of fasteners: that this delivery conforms to the order and the relevant standards, with results from specific inspection attached.

The relationship runs one way. §4.3.4 allows the results in an F3.1 to come from three places: raw material certificates 3.1 or 3.2, fastener in-process control, and fastener final inspection. So the chemical composition in an F3.1 may have come across unaltered from the steel mill’s paper — and that paper does not, and cannot, carry the hardness of your fastener lot.

That is why “3.1 required” does not constitute a requirement on a purchase order. It does not say whose 3.1, and it does not say whether you want evidence at the material layer or at the finished-part layer. Both can be called 3.1, and which one you get is the supplier’s choice rather than yours.

The four types, and who signs

Table 1 in §4.3.1 sets them out in four columns: type and name, when, content, validation. The fourth column is the one worth reading, because it is not worded the same way down all four rows.

ISO 16228:2017 Table 1, the validation column
Type	Content	Validation
F2.1	Declaration of conformance, without results	The manufacturer or distributor authorized representative
F2.2	With results based on non-specific inspection	The manufacturer authorized representative
F3.1	With results from specific inspection	The manufacturer or distributor authorized representative
F3.2	With results from specific inspection	The manufacturer’s or distributor’s authorized representative and either the purchaser authorized representative or the external authorized representative

F2.2 is the only row without “or distributor”. The body text in §4.3.3 matches: issued by the manufacturer, full stop. The other three all say issued by the manufacturer or distributor.

It is easy to read that as F2.2 being the stricter type. It means close to the opposite. An F2.2 carries results from non-specific inspection, which need not come from your delivery, and §4.3.3 makes it the manufacturer’s responsibility to determine the correlation between those results and the delivered fasteners. Only whoever ran the process knows that correlation, so a distributor has no standing to originate one.

Two of the terms repay a look at the definitions. §3.1 defines the authorized representative as a person authorized as a quality assurance representative to validate and sign inspection documents on behalf of the supplier or the purchaser; §3.2 defines the external authorized representative as a third party agreed between the purchaser and the supplier, or a purchaser’s requested inspection representative, or one designated by an official regulation. §3.3 says validation means confirming the content and final approval by means of signature.

⚠️ One thing is easy to carry across by mistake. EN 10204’s phrase for its 3.1, "independent of the manufacturing department", does not appear in ISO 16228’s Table 1 or in §4.3.2 to §4.3.5, which say "authorized representative" and define that by reference to quality assurance. ⚠️⚠️ Do not read that as "ISO 16228 has no independence requirement for the signatory." §5.9 is titled Validation of the inspection document, and it falls outside the preview I can read. What I can say is narrower: the phrase does not appear in the clauses I read.

A distributor can issue an F3.1, and the rules split distributors three ways

§5.4 is called Inspection document sources, and it sets out who may generate what in three groups. The manufacturer’s group is the shortest: it may generate F2.1, F2.2, F3.1 or F3.2, and may transfer original data from its own suppliers into its document, provided full traceability is ensured and the test/inspection results of the original document are not modified.

The two distributor groups are written in much more detail, and the detail cuts both ways.

Pass-through and repackaging distributors may generate F2.1 or F2.2 only by transferring data from the manufacturer’s F2.1 or F2.2; but they may generate F3.1 or F3.2 themselves; they may supply the manufacturer’s incoming document as it stands; and they may transfer original data from the manufacturer’s F3.1 into their own F3.1, again provided traceability holds and results are not modified
The alteration distributor carries one more duty: it shall test and/or inspect the properties which have been altered. It may transfer F2.2 data from the manufacturer only where the reported properties have not been altered, and must then test the altered properties and add its own results

So “who issued this F3.1” is a question with an answer, and the answer is not always the manufacturer. §5.4 adds a general rule on top: data transferred from an external source shall be validated by the supplier before inclusion, and the supplier is responsible for the conformity and traceability of that data.

⚠️⚠️ Then comes the last sentence of §5.4, the sharpest line in the whole preview: transferring of non-specific test/inspection results from F2.2 (or from 2.2 for material) into an F3.1 inspection document is not allowed.

What it closes is a very specific route: you hold only non-specific results, you put them under a different heading in the F3.1 format, and they now look like specific inspection. The standard does not leave that to judgement. It says is not allowed.

On the lot number, two types say should and two say shall

§5.1 covers all four types in one sentence, and that sentence contains two different modals.

F2.1 and F2.2 should include the fastener manufacturing lot number of the delivered fasteners; a trace lot number may replace or complement it
F3.1 and F3.2 shall include the fastener manufacturing lot number of the delivered fasteners

So an F3.1 with no lot number fails, on that point, the type it claims to be. This site made the same point in how to read a mill certificate — a certificate that lists results but carries no heat number is not doing the one thing the document is for. The difference is that there it was an inference, and here it is a clause.

⚠️ Lot number and heat number are still two different things. ISO 16228 requires the fastener manufacturing lot number. Whether that number can be traced back to the melt the steel came from is a separate level of traceability you have to write into the order yourself. The type number does not guarantee it — a point this site made before, and one that survives reading the clauses.

Three clauses that move the responsibility to the buyer

§5.1 and §5.3 contain three sentences that all run the same direction: having the document is not the end of the job.

"Even when receiving an inspection document, the purchaser is responsible for the approval of the delivered fasteners by acceptance inspection procedures in accordance with ISO 3269 unless otherwise agreed." The document does not replace incoming inspection. ISO 3269 is the standard behind what passing inspection means
"Each inspection document is only valid for the as-delivered condition of the related fasteners." Any further processing after delivery — the example the standard gives is coating — may invalidate all or part of the content. So if you send them out for plating after goods-in, the document no longer covers what leaves
⚠️⚠️ "Upon opening the original packaging, the purchaser assumes full responsibility for all subsequent traceability." That is §5.3 verbatim. The handover point is opening the box — not acceptance, not putting it in stores, not signing for it

The third one is worth a second pass. It means that tipping four boxes into one parts bin destroys traceability in that single movement, and the responsibility for it is yours. §5.3 has a matching sentence on the supplier’s side: fasteners shall be fully traceable by the manufacturing lot number (or trace lot number), and to maintain lot integrity, manufacturing lots shall not be commingled.

§5.3 also leaves a way back: in case of dispute, the supplier shall be able to provide all necessary documentation and test/inspection records related to the manufacturing lot number (or trace lot number). §5.2 puts a clock on that: the fastener supplier issuing an inspection document shall maintain in-process control and/or final test/inspection records, in hardcopy or electronically, for a minimum period of three years.

So “will this still be traceable in three years” has a floor, and the floor is exactly three years. Longer than that is something you write into the order.

What F3.2 actually adds: the sampling changes hands

The difference between F3.2 and F3.1 is usually described as an extra third-party countersignature. §5.6 describes something more substantial than that.

"In case of test reports F3.2, sampling is under the responsibility of either the purchaser authorized representative or the external authorized representative." The supplier does not sample and then have someone else sign it off; the act of sampling itself changes hands.

The same clause carries a requirement that applies to all three test reports: for F2.2, F3.1 and F3.2 the quantity of tested or inspected parts shall be included in the report for each test, except where all results are reported. If you need a specific quantity tested for particular tests, §5.6 says that is agreed at the time of the order.

§5.5 settles another common worry: tests and inspection may be subcontracted. The results can be attached as a complete report or transferred into the document, under the responsibility of the supplier issuing it. The subcontracted samples must be traceable by manufacturing lot number (or trace lot number), and the subcontractor’s report must reference that number. So “this was tested outside” is not itself a problem. “This cannot be traced back to the lot” is.

One thing the standard says it does not do

The last paragraph of the scope in §1: this document does not apply to special-purpose or specially engineered applications requiring other types of procedures, and the example it gives is initial samples.

So whatever a sample approval needs, it is not one of these types answering it. What the sample stage is actually testing, and why it has to run down the production line, is in the samples arrived, now what.

§1 also repeats the naming point, and it is worth copying out because it is the standard’s own note: the term “certificate” is in common use, however for fastener inspection documents the terminology to be used is “test report”.

The introduction is worth noticing too, because it puts the weight of the evidence back onto the process: data in inspection documents may be collected from in-process control during manufacture and/or from final control on the finished fasteners based on sampling, and in-process control within a certified quality assurance system operated by the manufacturer gives the most reliable information about conformance.

Three lines to change on the purchase order

This site has published five lines before. Three of them can now be written more precisely.

Turning the clauses into order text
Was	Becomes	Basis
3.1 required	Fastener: ISO 16228 F3.1. Material: EN 10204 3.1 (or ISO 10474 3.1)	§4.1, §4.3.4
Lot number required	F3.1 shall state the fastener manufacturing lot number, and that number shall trace back to the steel heat number	§5.1 for the shall; the heat-number layer is added by us
Inspection required	Quantity tested shall be stated per test; for F3.2, sampling to be performed by our representative	§5.6

One line is new, and it is a single sentence: "If we process these after delivery (for example, surface treatment), state which items in this document will no longer apply." That turns the as-delivered clause in §5.1 into a question the other side has to answer.

References, and how far the reading goes

ISO 16228:2017, Fasteners — Types of inspection documents. First edition 2017-11, ISO/TC 2/SC 7, ICS 21.060.01, 26 pages, catalogue number 55935. Confirmed on iso.org: Stage 90.93, International Standard confirmed, last reviewed and confirmed in 2022, so this version remains current; a corrected French version was issued 2018-12.
⚠️⚠️ How far this page reads: the free preview, which stops on page 6 of the body, part-way through §5.7. That covers the scope, normative references, terms, the whole of clause 4, and §5.1 to §5.6 plus the opening of §5.7. Table 2, §5.8, §5.9 Validation of the inspection document, clause 6 (required content for each type), clauses 7 and 8, Annex A, Annex B and the bibliography were not read, so this page does not state which fields each type must carry, does not state the minimum reportable results, and does not claim the standard has no independence requirement for the signatory.
⚠️ This site has not read EN 10204 itself. The four-type table in how to read a mill certificate rests on secondary sources, and this page does not take the opportunity to write EN 10204’s clauses — it records only that ISO 16228 §4.1 points the material documents there. ISO 10474 is likewise named, not read.
ISO 3269, Fasteners — Acceptance inspection: the standard named in §5.1. This site’s account of it is in what passing inspection means.
ISO 1891-4:2017 — the source of the terms in §3, including manufacturing lot number, trace lot number and commingling. This site has not read it.

This page covers step 6, the documentation. The whole order is substrate, thread, head, drive, finish, documentation, and why doing it out of order is rework rather than a tweak is in specifying a screw.

Common questions

Is “3.1 required” enough on a purchase order?

No, and the reason is more specific than a name collision. ISO 16228:2017 §4.1 hands the material documents 2.1, 2.2, 3.1 and 3.2 over to ISO 10474 or other relevant technical specifications — the example the standard gives is EN 10204 — and governs only F2.1, F2.2, F3.1 and F3.2. §4.3.4 then says the results in a fastener F3.1 shall be taken from raw material certificates (3.1 or 3.2), fastener in-process control and/or final inspection. The two documents sit upstream and downstream of each other, so the order needs two lines: the fastener type, and the material type.

Can a supplier put F2.2 data into an F3.1?

No. The last sentence of ISO 16228 §5.4 is direct about it: transferring of non-specific test/inspection results from F2.2 (or from 2.2 for material) into an F3.1 inspection document is not allowed. It closes a very specific route — you hold only non-specific results, you put them under a different heading in the F3.1 format, and they now look like specific inspection. The standard says “is not allowed”, which leaves no room for judgement.

Can a distributor issue an F3.1?

Yes. The body text of §4.3.4 says issued by the manufacturer or distributor, and the validation column of Table 1 says the manufacturer or distributor authorized representative. §5.4 splits distributors three ways: pass-through and repackaging distributors may generate F3.1 or F3.2 themselves but may produce F2.1 or F2.2 only by transferring the manufacturer’s data; the alteration distributor carries one more duty — it shall test or inspect the properties that have been altered. ⚠️ Going the other way, F2.2 is the only one of the four types with no “or distributor”, because §4.3.3 makes determining the correlation between the results and the delivered fasteners the manufacturer’s responsibility.

Do we still need incoming inspection after receiving an F3.1?

Yes. §5.1 states it: even when receiving an inspection document, the purchaser is responsible for the approval of the delivered fasteners by acceptance inspection procedures in accordance with ISO 3269 unless otherwise agreed. The same clause adds two sentences in the same direction — the document is valid only for the as-delivered condition, and further processing after delivery (the standard’s example is coating) may invalidate all or part of it. And §5.3 says that upon opening the original packaging, the purchaser assumes full responsibility for all subsequent traceability. The handover point is opening the box.

What does F3.2 add over F3.1?

It is usually described as an extra countersignature, but §5.6 describes something more substantial: in case of test reports F3.2, sampling is under the responsibility of either the purchaser authorized representative or the external authorized representative. It is not only the signature that changes hands; it is the act of sampling. §5.6 also requires, for F2.2, F3.1 and F3.2 alike, that the quantity of tested or inspected parts be included in the report for each test, except where all results are reported.

How long must the supplier keep the records?

§5.2: the fastener supplier issuing an inspection document shall maintain in-process control and/or final test/inspection records, in hardcopy or electronically, for a minimum period of three years. That is the floor the standard sets; anything longer goes into the order. §5.3 separately requires that, in case of dispute, the supplier be able to provide all necessary documentation and records related to the manufacturing lot number or trace lot number.

Can initial samples be specified using ISO 16228 types?

No — the standard excludes them itself. The scope in §1 says the document does not apply to special-purpose or specially engineered applications requiring other types of procedures, and the example it gives is initial samples. §1 also repeats the naming point: the term “certificate” is in common use, however for fastener inspection documents the terminology to be used is “test report”.

Two documents called 3.1: one is the fastener’s, one is its material’s