Quick Answer
Quick Answer
BS EN 10025 is the UK-adopted structural steel standard covering hot-rolled products for grades S235 to S460. Post-Brexit, structural steel placed on the Great Britain market must carry UKCA marking under the UK Construction Products Regulation (UK CPR) — CE marking is no longer accepted in GB as of 1 July 2025. Northern Ireland continues to accept CE marking under the Windsor Framework. Mill certificates must reference a UKAS-accredited body and include a UK Declaration of Performance.
BS EN 10025 governs hot-rolled structural steel products — flats, sections, and plates — for use in load-bearing steel structures. The standard was originally harmonised across Europe as EN 10025; the UK retained it post-Brexit as a UK-adopted standard through BSI, but the conformity marking regime diverged completely on 1 July 2025. From that date, products placed on the Great Britain market (England, Scotland, Wales) require UKCA marking supported by a UK-issued Declaration of Performance and a UKAS-notified body's involvement. The Republic of Ireland and Northern Ireland remain under the CE/EU system.
Scope and Applicability
BS EN 10025 applies to hot-rolled steel products for structural purposes, specifically:
- Flat and long products (flats, plates, wide flats, sections, bars)
- Thickness and width ranges defined per part
- Grades in six sub-parts covering different alloy and toughness families
The standard does not cover cold-formed sections (see EN 10219), hollow sections (EN 10210/10219), reinforcing bar (BS 4449), or stainless steel.
UK CPR applicability: Structural steel products that are construction products under the UK CPR — meaning they are permanently incorporated into construction works — require UKCA marking when placed on the GB market. This covers standard structural sections and plates used in building frames and bridges.
Grade Coverage
BS EN 10025 is published in six parts. Each part addresses a specific steel family:
| Part | Title | Grades |
|---|---|---|
| Part 1 | General technical delivery conditions | — (common clauses) |
| Part 2 | Technical delivery conditions for non-alloy structural steels | S235, S275, S355, S450 |
| Part 3 | Normalized/normalized rolled weldable fine grain structural steels | S275N/NL, S355N/NL, S420N/NL, S460N/NL |
| Part 4 | Thermomechanical rolled weldable fine grain structural steels | S275M/ML, S355M/ML, S420M/ML, S460M/ML |
| Part 5 | Structural steels with improved atmospheric corrosion resistance (weathering) | S235W, S355W, S355WP |
| Part 6 | Flat products of high yield strength structural steels in the quenched and tempered condition | S460Q/QL/QL1, S500Q/QL/QL1, S550Q/QL/QL1, S620Q/QL/QL1, S690Q/QL/QL1 |
Suffix letters indicate toughness sub-grades: J0 = 0 °C Charpy, J2 = −20 °C, K2 = −20 °C (higher energy), N/NL = normalized, M/ML = thermomechanical, Q/QL/QL1 = quenched and tempered.
Chemical Composition Requirements
Part 2 — Non-Alloy Structural Steels (ladle analysis, wt% max unless ranged)
| Grade | C max | Mn max | Si max | P max | S max | N max | CEV max |
|---|---|---|---|---|---|---|---|
| S235JR | 0.17 | 1.40 | — | 0.035 | 0.035 | 0.012 | 0.35 |
| S235J0 | 0.17 | 1.40 | — | 0.030 | 0.030 | 0.012 | 0.35 |
| S235J2 | 0.17 | 1.40 | — | 0.025 | 0.025 | — | 0.35 |
| S275JR | 0.21 | 1.50 | — | 0.035 | 0.035 | 0.012 | 0.40 |
| S275J0 | 0.18 | 1.50 | 0.40 | 0.030 | 0.030 | 0.012 | 0.40 |
| S275J2 | 0.18 | 1.50 | 0.40 | 0.025 | 0.025 | — | 0.40 |
| S355JR | 0.24 | 1.60 | 0.55 | 0.035 | 0.035 | 0.012 | 0.45 |
| S355J0 | 0.20 | 1.60 | 0.55 | 0.030 | 0.030 | 0.012 | 0.45 |
| S355J2 | 0.20 | 1.60 | 0.55 | 0.025 | 0.025 | — | 0.45 |
| S355K2 | 0.20 | 1.60 | 0.55 | 0.025 | 0.025 | — | 0.45 |
| S450J0 | 0.20 | 1.70 | 0.60 | 0.030 | 0.025 | 0.025 | 0.47 |
CEV = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15. Values above are for t ≤ 40 mm; thicker product has relaxed limits — refer to the current BSI edition.
Part 3 — Normalized Fine Grain Steels (selected grades)
| Grade | C max | Mn | Si max | P max | S max | Al min | Nb | V | Ti |
|---|---|---|---|---|---|---|---|---|---|
| S355N | 0.18 | 0.90–1.65 | 0.50 | 0.030 | 0.025 | 0.020 | ≤ 0.05 | ≤ 0.12 | ≤ 0.05 |
| S355NL | 0.18 | 0.90–1.65 | 0.50 | 0.025 | 0.020 | 0.020 | ≤ 0.05 | ≤ 0.12 | ≤ 0.05 |
| S420N | 0.20 | 1.00–1.70 | 0.50 | 0.030 | 0.025 | 0.020 | ≤ 0.05 | ≤ 0.12 | ≤ 0.05 |
| S460N | 0.20 | 1.00–1.70 | 0.60 | 0.030 | 0.025 | 0.020 | ≤ 0.05 | ≤ 0.12 | ≤ 0.05 |
Mechanical Properties
Part 2 — Non-Alloy Grades (by nominal thickness)
| Grade | ReH min MPa (t ≤ 16 mm) | ReH min MPa (16 < t ≤ 40 mm) | ReH min MPa (40 < t ≤ 80 mm) | UTS MPa | A min % (t ≤ 40 mm) |
|---|---|---|---|---|---|
| S235 | 235 | 225 | 215 | 360–510 | 26 |
| S275 | 275 | 265 | 255 | 410–560 | 23 |
| S355 | 355 | 345 | 335 | 470–630 | 22 |
| S450 | 450 | 430 | — | 550–720 | 17 |
Elongation measured on gauge length L₀ = 5.65 √S₀ (proportional specimen). Impact test requirements differ by Charpy sub-grade (JR/J0/J2/K2) — see impact test section below.
Part 3 — Normalized Fine Grain Grades
| Grade | ReH min MPa (t ≤ 16 mm) | ReH min MPa (16 < t ≤ 40 mm) | ReH min MPa (40 < t ≤ 63 mm) | UTS MPa | A min % |
|---|---|---|---|---|---|
| S275N | 275 | 265 | 255 | 370–530 | 24 |
| S355N | 355 | 345 | 335 | 470–630 | 22 |
| S420N | 420 | 400 | 390 | 520–680 | 19 |
| S460N | 460 | 440 | 430 | 540–720 | 17 |
Impact Test Requirements
Charpy V-notch tests per EN ISO 148-1. Test temperature and minimum energy per sub-grade:
| Sub-grade suffix | Test temperature | Min. absorbed energy (longitudinal, 3 specimens avg.) |
|---|---|---|
| JR | +20 °C | 27 J |
| J0 | 0 °C | 27 J |
| J2 | −20 °C | 27 J |
| K2 | −20 °C | 40 J |
| NL / ML | −50 °C | 27 J |
| QL1 | −60 °C | 30 J |
For the NL (normalized low) and ML (thermomechanical low) sub-grades, the minimum individual value must be ≥ 70% of the average minimum. Impact testing is mandatory; the MTC must report individual specimen results and the 3-specimen average.
Additional Tests
The following supplementary tests may be invoked on the purchase order:
| Test | Reference standard | When typically required |
|---|---|---|
| Z-quality (through-thickness properties) | EN 10164 | Welded T- and cruciform joints with high restraint |
| Ultrasonic examination | EN 10160 | Thick plate for critical nodes |
| Product chemical analysis (check analysis) | EN ISO 14284 | Quality audits, dispute resolution |
| Surface quality enhanced | Class A or B per EN 10163 | Architectural/visible surfaces |
| Flatness tolerance enhanced | EN 10029 Class N or S | Machined base plates |
UKCA vs CE Marking
The post-Brexit conformity marking position for structural steel in the UK is:
| Territory | Marking required | Notified body type | Applicable regulation |
|---|---|---|---|
| Great Britain (England, Scotland, Wales) | UKCA | UKAS-approved body (UK Approved Body) | UK Construction Products Regulation (UK CPR) |
| Northern Ireland | CE or UKCA | EU notified body or UK(NI) approved body | EU CPR (Windsor Framework) |
| EU / Republic of Ireland | CE | EU notified body | EU CPR 305/2011 |
Transition timeline: CE marking was accepted in GB under a transitional period that expired on 30 June 2025. From 1 July 2025, UKCA is mandatory for all new structural steel placed on the GB market. Existing stock imported before that date retains CE as evidence of conformity.
UKCA marking on structural steel: The UKCA mark itself is not physically affixed to steel products in the same way as consumer goods; conformity is demonstrated through the UK Declaration of Performance (UK DoP) and accompanying mill test certificate. The UK DoP must:
- Reference the UK-adopted standard (BS EN 10025 Parts 1–6 as applicable)
- Name the UK Approved Body (UKAS-accredited) and its UK(AB) number
- State the system of attestation of constancy of performance (SACP) — for structural steel this is System 2+
- Declare the essential characteristics and their performance levels
Cross-Standard Equivalents
| BS EN 10025 Grade | Closest ASTM equivalent | Closest IS equivalent | JIS equivalent |
|---|---|---|---|
| S235JR | A36 (approx.) | IS 2062 E250 | SS400 |
| S275JR | A36 (approx.) | IS 2062 E275 | SM275 |
| S355J2 | A572 Gr 50 (approx.) | IS 2062 E350 | SM490 |
| S420N | A572 Gr 60 (approx.) | IS 2062 E410 | — |
| S460N | A572 Gr 65 / A913 Gr 65 | IS 2062 E450 | — |
| S690Q | A514 (approx.) | — | HT690 |
Equivalences are approximate. Chemical limits and impact test requirements differ. Always verify against the actual standard before substitution on a project.
MTC Verification Checklist
A compliant UK MTC for BS EN 10025 material under UKCA should contain:
| # | Field | What to check |
|---|---|---|
| 1 | Standard reference | "BS EN 10025-2:2019" (or relevant part and edition) |
| 2 | Grade and sub-grade | Full designation e.g. "S355J2+N" including delivery condition suffix |
| 3 | UKCA / UK DoP reference | UK Declaration of Performance number and issuing UK Approved Body name + UK(AB) number |
| 4 | Heat number | Must match physical marking on product |
| 5 | Chemical analysis | Ladle analysis values within the standard limits for the declared grade and thickness |
| 6 | Mechanical test results | ReH, Rm, A% and (if applicable) Charpy energy at the correct temperature |
| 7 | Product dimensions | Nominal thickness confirmed — determines which column of the property table applies |
| 8 | Authorised signature | Signed by the mill's responsible test authority per EN 10204 Type 3.1 or 3.2 |
TestCert stores the BS EN 10025 composition and mechanical limits as structured data keyed by grade, sub-grade, and thickness range, automatically flagging any MTC value that falls outside specification without requiring manual table lookup.
Frequently Asked Questions
Is CE marking still accepted for structural steel in the UK?
No. The CE marking transitional period for Great Britain expired on 30 June 2025. From 1 July 2025, UKCA marking (supported by a UK Declaration of Performance from a UKAS-approved body) is required for structural steel placed on the GB market. Northern Ireland is the exception: CE marking remains valid there under the Windsor Framework.
What is the difference between BS EN 10025 and EN 10025?
The technical content — grades, chemical limits, mechanical properties — is essentially identical. The difference is the conformity marking framework. BS EN 10025 is the BSI-published UK adoption; EN 10025 is the CEN-published EU standard. UK manufacturers reference BS EN 10025 in their UK DoP; EU manufacturers reference EN 10025 in their EU DoP. Both draw on the same underlying technical data.
What is SACP System 2+ for structural steel?
System 2+ means the manufacturer operates a factory production control (FPC) system certified by a UK Approved Body, and that UK Approved Body conducts an initial inspection of the factory and ongoing surveillance. The manufacturer is responsible for performing and declaring all product tests. System 2+ is the attestation level specified in the UK CPR for structural steel — it requires third-party FPC certification but not third-party product testing on every batch.
Which delivery condition suffix should I specify when ordering S355?
The most common delivery conditions are: +AR (as-rolled), +N (normalized or normalized rolled), +M (thermomechanical rolled), and +Q (quenched and tempered). S355J2+N is widely stocked. For improved through-thickness properties or Z-quality, also invoke EN 10164 Z25 or Z35. For seismic or highly restrained welded connections, S355J2+M offers better Charpy values at thicker sections.
Does BS EN 10025 cover hollow sections?
No. Hollow sections (structural tubes) are covered by EN 10210 (hot-finished) and EN 10219 (cold-formed). These are separate standards with their own chemical and mechanical requirements, though they share some grade designations with EN 10025.
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