Scaffold Beam Clamp (Girder Coupler): What EN 74-1 Covers and What to Ask

The couplers covered in the other type guides on this site join tube to tube. The girder coupler joins a scaffold tube to a steel beam. That one difference puts it outside Part 1 of the European coupler standard, the document those guides are built on, and it is the reason this page has no load table.

What follows is what the standards and the supplier data in our source ledger say about this fitting, where they say nothing, and what a buyer has to get from the supplier instead — flange range, load direction, the pair-or-single basis of any figure, and the document behind a test claim.

What a beam or girder coupler is, and what it is called

The fitting has two ends with two different jobs. One end holds a scaffold tube. The other end holds onto the flange of a steel section. The four types in Table 1 of BS EN 74-1:2022+A1:2025 all join tube to tube — two tubes crossing at a right angle, two crossing at any angle, two lying parallel, and two joined end to end coaxially. A girder coupler has a tube on one side only.

The names vary more than the object does.

The last two rows of that table are worded differently on purpose. GB 15831-2006 is a standard we have read in full, so the absence of a beam coupler from its type codes is a fact about the document. For AS/NZS 1576.2:2016 our ledger holds the clauses that concern right-angle, swivel, end-to-end, parallel, check and putlog couplers, not a full transcription, so the absence is a fact about what we hold.

Where it sits in the EN 74 family

BS EN 74-1:2022+A1:2025, the current edition, sets out its own boundaries in two places. Its scope clause says it specifies materials, design requirements, strength classes, test procedures and assessment for right angle, swivel, sleeve and parallel couplers working by friction. Its introduction then divides the family into three parts: Part 1 for the common types of friction couplers, Part 2 for other, less common types, and Part 3 for plain base plates and loose spigot pins.

Everything that follows in Part 1 is built on those four types. Table 1 lists them, with the codes RA, SW, PA and SF. Table 2 assigns their classes — A, B, AA and BB for the right-angle coupler; A and B for the swivel, parallel and sleeve couplers. Table 8, the table of test parameters and specified values, has rows for those four types and no others. A girder coupler is not in Table 1, so it has no class in Table 2 and no row in Table 8.

The obvious next question is whether Part 2 picks it up. The introduction to Part 1 describes Part 2 only as covering other, less common types; it does not list them in the text we hold. We have not obtained EN 74-2. This site therefore does not say that EN 74-2 covers girder couplers, does not say that it does not, and attributes no requirement to it.

The superseded edition was framed around tube as well. EN 74:1988, published in the UK as BS 1139-2.1:1991, applied to couplers, loose spigots and base-plates for connecting steel tube of 48,3 mm outside diameter with a nominal wall of at least 3,2 mm, and framed its requirements as the assessment of prototypes. The coupler codes our ledger records for that edition are RA, SW, PA, SF, SS and LS; none of them is a beam or girder coupler. Because that list is our ledger’s summary rather than a transcription of the whole document, this page reports it as what our sources record, not as a statement about everything the 1988 edition contained.

The sequence of coupler-standard editions from BS 1139 to the current EN 74-1 is tabled in the coupler types guide. This page compares only the two editions we have read, EN 74:1988 and BS EN 74-1:2022+A1:2025.

Why there is no load table on this page

A guide to a coupler type on this site ordinarily leads with the requirement table from the current standard. This one cannot, and the reason matters more than the missing table, because “no figure” can mean three different things and they lead to different questions.

A standard can print a dash. Table 8 of BS EN 74-1:2022+A1:2025 uses an en dash where it deliberately sets no value — for example against several rows in the paired right-angle columns. A dash is the standard looking at a fitting and declining to set a figure for that property. That is not the girder coupler’s situation. It has no row in Table 8 at all, so there is not even a dash to report.

A standard can leave a fitting outside its type list. Table 1 of BS EN 74-1:2022+A1:2025 does not list the girder coupler, and the four type codes of GB 15831-2006 do not include one. We have read both documents, so these are facts about how the documents are structured. They say that neither document sets requirements for this fitting. They do not say the fitting is weak, untested or unsuitable.

Our sources may simply not record it. We have not obtained EN 74-2, the part the current edition names for less common coupler types. We hold AS/NZS 1576.2:2016 as clause extracts, not as a full text. We have not obtained GB/T 15831-2023, which replaced GB 15831-2006. Any of those could contain requirements for a beam or girder coupler; no beam- or girder-coupler requirement from any of them is recorded in our ledger. That is a gap in what we hold, and it is reported as one.

What an “EN 74-1 Class B” label on a girder coupler can mean

Class letters in BS EN 74-1:2022+A1:2025 are defined type by type. Table 2 gives the right-angle coupler four classes and the swivel, parallel and sleeve couplers two each, and each class of each type is tied to its own rows in Table 8. There is no class for a type that is not in Table 1.

The clause 8 designation makes the point in one string. Its form is EN 74-1 <type> <class> <corrosion class> <inspection level>, and the standard’s own example is EN 74-1 RA BB C2 M. The type position takes one of the four Table 1 codes. There is no code to put there for a girder coupler, and so no Part 1 designation for one. Clause 9 requires the class to be part of the mark embossed or impressed on each coupler, which is why a class letter can appear on a fitting; what that letter is worth depends on the type and document behind it. How the full mark reads is in the coupler types guide.

A girder coupler listed or stamped “EN 74-1 Class B” is therefore carrying a letter that does not map to any requirement in Part 1. This page does not speculate about how such a label comes about. The questions that sort it out are the ones Part 1 itself sets up for the types it does cover:

• Which document is the test report written to, and which class in that document? If the answer is Part 1, ask which Table 1 type and which Table 8 rows the fitting was assessed against.
• Who assessed it? Clause 12 requires the assessment of a Part 1 coupler to be made by a person or organization other than the one that designed it.
• What does the product manual say? Clause 13 requires a Part 1 product manual to state the type and class and to identify the assessor, with a copy of the assessment statement.

The same logic applies to the general provisions of Part 1. Its bolt rules, its tightening procedure for the type test and its marking dimensions are requirements for its four coupler types, and the production-control frequencies in its Annex B are informative recommendations for those same types. A girder coupler supplier may choose to meet them, and saying so is a fair claim to ask about, but the standard does not require it of this fitting. The values themselves are in the double coupler guide and the coupler types guide.

The tube side and the beam side

It helps to treat the two ends as two separate specifications.

The tube end is familiar ground. EN 74:1988 was written for steel tube of 48,3 mm outside diameter with a nominal wall of at least 3,2 mm, and BS EN 74-1:2022+A1:2025 covers couplers for 48,3 mm outside-diameter steel and aluminium tube meeting EN 12811-1, EN 12811-2 and EN 12810-1. Those scope statements belong to the couplers the two editions specify. They do not establish which tube a given girder coupler fits: our ledger records no tube size against any girder coupler, so the tube diameter and wall have to be stated on the order and confirmed by the supplier for the exact product.

The beam end is where our sources go quiet. The ledger holds no flange thickness range, no beam section, no statement of the direction in which a girder coupler is loaded and no rule on whether figures are given per fitting or per pair. Those are not details this page has left out for brevity; they are the product data a supplier has to supply, because none of that product data is recorded in our source ledger.

That gap shapes what a load figure is worth when one does appear on a quotation. For the four Part 1 types a buyer can at least check a quoted number against a Table 8 row and ask whether it is that row. For a girder coupler there is no row to check against, so every figure needs its basis stated alongside it:

1. One fitting or a pair. A figure stated for a pair does not describe one fitting, and a figure for one fitting does not describe a pair.
2. Which direction. Along the beam, across it, or pulling away from the flange — a figure for one is not a figure for another.
3. On what. Which beam section and flange thickness the test used, and which tube.
4. What kind of number. A type-test value on a prototype, or a working load after a factor. For its own four types, clause 6.2.1 of BS EN 74-1:2022+A1:2025 sends the reader to EN 12811-1 and EN 12812 for the characteristic values and safety coefficients to be applied in use; a girder coupler figure needs its basis stated by whoever issues it.

United States, Australia and New Zealand, China

United States. The 29 CFR 1926 paragraphs in our ledger set rules for scaffolds and their components, and none of them names a beam or girder coupler. Three of them reach it all the same. Paragraph 1926.452(b)(9) requires that “Couplers shall be of a structural metal, such as drop-forged steel, malleable iron, or structural grade aluminum” and prohibits grey cast iron. Paragraph 1926.451(a)(1) requires “each scaffold and scaffold component” to support, without failure, its own weight and at least 4 times the maximum intended load applied or transmitted to it — a factor applied in design, not a rating for any fitting. Paragraph 1926.452(b)(10) requires tube and coupler scaffolds over 125 feet in height to be designed by a registered professional engineer and points to non-mandatory Appendix A for examples below that height. OSHA’s fact sheet FS-3760, which states that it imposes no new compliance requirements, adds that scaffolds must be designed by a qualified person. For a US buyer, then, the girder coupler question arrives through the design: the designer needs a figure for the fitting, and the figure has to come from the supplier’s data.

Australia and New Zealand. AS/NZS 1576.2:2016 is titled Couplers and accessories. The clauses our ledger holds from it cover right-angle, swivel, end-to-end, parallel, check and putlog couplers; none concerns a beam or girder coupler, and we have not recorded whether the standard has such a clause. Two clauses we do hold bear on how a claim should be read. Clause 1.5 requires marking on each coupler and accessory, excluding baseplates, so a girder coupler sold as conforming to AS/NZS 1576.2:2016 would be expected to carry the maker’s name or trademark and a batch-traceable code. Clause 1.6 deems couplers already tested to EN 74-1:2005 to comply, but it names two kinds of fitting only — Class B right-angle couplers and Class A swivel couplers. It gives a girder coupler no route in. The rest of the Australian and New Zealand regime is summarised in the coupler types guide.

China. GB 15831-2006, the Chinese national standard for steel tube scaffold couplers, has four type codes: Z for the right-angle coupler, U for the swivel, D for the sleeve and DZ for the base-plate. Its model designation, of the form GKZ48A GB 15831—2006, has no code for a beam coupler to occupy. GB 15831-2006 was withdrawn on 1 December 2023 and replaced by GB/T 15831-2023; we have not read the replacement and do not state whether it covers beam couplers. A Chinese quotation for a girder coupler that cites GB 15831-2006 is citing a withdrawn standard that has no type for the fitting; the question for the factory is the same as for a European claim — which document, which clause, and where is the report. The wider Chinese picture is in the double coupler guide.

What suppliers list

One supplier entry in our ledger concerns this fitting. Altrad Generation’s scaffold fittings catalogue lists a girder coupler, code 26201, at 1.56 kg (accessed 16 September 2026). Our ledger records the code and the weight and nothing else against it: no manufacturing process, no standard reference and no load figure. The other UK fittings range in our ledger, London Scaffolding Supplies, has no girder coupler entry recorded.

One supplier is below the three-independent-vendor bar our ledger sets before a weight may be published as a typical figure or a range, so 1.56 kg is Altrad Generation’s catalogue weight for one product and not a market figure. A girder coupler from another maker, or one made for a different flange range, is a different product with its own weight, and a container plan built on 1.56 kg is built on Altrad Generation’s 26201.

What to put on the order for a girder coupler

The purchase-order list in the coupler types guide is written around the EN 74-1 types; its class, marking and test-report points assume a Part 1 type and class, which a girder coupler does not have. For this fitting, the six lines below take their place.

1. Identify the product, not the category. The supplier’s code and its data sheet or drawing, in the way Altrad Generation identifies its girder coupler as 26201. “Beam clamp” alone does not identify a product.
2. State the beam. The beam section and the flange thickness the fittings will go on, and ask the supplier to confirm that the product is made for that flange. Our sources hold no flange range for any girder coupler, so this has to come from the supplier’s data.
3. Name the document behind any test claim. Which document the type-test report is written to, which clause, and who carried out the assessment. A report to BS EN 74-1:2022+A1:2025 would have to say which Table 1 type it treated the fitting as; if it cannot, the claim needs another basis.
4. Get any load figure with its basis. Per fitting or per pair, the direction of load, the beam and tube it was tested on, and whether it is a type-test value or a working load. A figure without those four items cannot be used by a designer.
5. Ask what the class letter means. If the listing or the marking carries “Class A” or “Class B”, ask which document defines that class for this fitting. Part 1 does not define one.
6. State the tube. The outside diameter and wall thickness of the tube in use, with the supplier’s confirmation that the exact product is made for it.

The joint-by-joint table in tube and clamp scaffolding explained lists the girder coupler as the fitting for a tube-to-beam-flange joint; the lines above are what turn that entry into an orderable product.

Send a girder-coupler enquiry with the beam section, flange thickness and tube details so the requested product is identifiable.

Sources

1. BS EN 74-1:2022+A1:2025 Couplers, spigot pins and baseplates for use in falsework and scaffolds — Part 1: Couplers for tubes (current edition; clause 1 and introduction, Tables 1 and 2, clauses 6.2.1, 8, 9, 12 and 13). BSI product page — accessed 2026-09-17
2. BS 1139-2.1:1991 (EN 74:1988) Metal scaffolding — Part 2: Couplers — Section 2.1: Specification for steel couplers, loose spigots and base-plates. Superseded; cited for its scope wording and coupler codes. Current edition sold by BSI — accessed 2026-09-16
3. 29 CFR 1926.452(b) Tube and coupler scaffolds, paragraphs (b)(9) and (b)(10) (Cornell LII) — accessed 2026-09-16
4. 29 CFR 1926.451(a)(1) Scaffolds — General requirements, capacity (eCFR) — accessed 2026-09-16
5. OSHA Fact Sheet FS-3760, Tube and Coupler Scaffolds — Planning and Design (11/2014) — accessed 2026-09-16
6. AS/NZS 1576.2:2016 Scaffolding — Part 2: Couplers and accessories (clauses 1.5 and 1.6). Standards New Zealand product page — accessed 2026-09-16
7. GB 15831-2006 《钢管脚手架扣件》 Steel tube scaffold couplers — type codes, clause 4; withdrawn 2023-12-01 and replaced by GB/T 15831-2023. Official catalogue record, 全国标准信息公共服务平台 — accessed 2026-09-16
8. Altrad Generation — Scaffold fittings catalogue (girder coupler code 26201, with catalogue weight) — accessed 2026-09-16