BS 4449:2005+A3:2016 · WELDABLE RIBBED REINFORCEMENT · B500B & B500C
Procure BS 4449 ribbed reinforcing steel for concrete projects, with clear B500B and B500C options, nominal sizes, tensile criteria, welding-related chemical controls and lot-specific inspection requirements. Send your bar schedule for a tailored factory quotation.
Compare B500B & B500C ↓
Standard grades and sizes are technical references. Product-specific stock, origin, certification scope and delivery dates are confirmed for each enquiry.
A single procurement entry for BS 4449 bar, coil and decoiled reinforcement, with dedicated grade pages when detailed acceptance criteria matter.
BS 4449:2005+A3:2016 defines weldable reinforcing steel for use in concrete, covering ribbed bars, coils and decoiled products. It distinguishes the B500A, B500B and B500C ductility classes, each with 500 MPa characteristic yield strength.
This page focuses on B500B and B500C, which have separate product pages for the specified tensile/yield ratios, elongation and testing requirements.
Start with the structural design and approved grade. Then specify the nominal diameter, straight-bar or coil supply, length or cutting schedule, ordered tonnage, certification and delivery requirements.
Submit grade, diameter, length, tonnage and required mill documentation for line-by-line confirmation.
Compare both available grade pages before finalizing a construction reinforcement order.
Class B ductility: a 500 MPa characteristic yield class with Rm/Re ≥1.08 and Agt ≥5.0%. Frequently specified where the approved design requires B-grade reinforcement.
Class C ductility: a 500 MPa characteristic yield class with Rm/Re ≥1.15 and <1.35, and Agt ≥7.5%. Choose only where the approved schedule specifies Class C.
All three BS 4449 classes share the 500 MPa characteristic yield strength. The tensile/yield-strength ratio and Agt distinguish their ductility requirements.
| Mechanical criterion | B500A (context) | B500B — Class B | B500C — Class C |
|---|---|---|---|
| Characteristic yield, Re | 500 MPa | 500 MPa | 500 MPa |
| Characteristic Rm/Re | ≥1.05* | ≥1.08 | ≥1.15 and <1.35 |
| Characteristic Agt | ≥2.5%* | ≥5.0% | ≥7.5% |
| Ductility class | A | B | C |
| Material reference | BS 4449 | BS 4449 | BS 4449 |
| Published detail page | Reference only | View B500B grade → | View B500C grade → |
Request grade-specific technical confirmation before accepting a proposal or changing the material schedule.
Use the steel product standard for material conformity and the bar scheduling standard for fabrication dimensions and shape codes.
Material specification for weldable reinforcing steel in bar, coil and decoiled form. Covers declared grades, characteristic tensile properties, chemistry, rib geometry, nominal mass, marking, test methods and conformity requirements.
Cutting and bending specification for reinforcement schedules, dimensional notation, bar shape codes and fabrication tolerances. It supports processing instructions but does not replace BS 4449 material testing.
Specify the complete grade and standard edition to avoid confusion with rebar grades from other national systems.
| Order field | Specification reference |
|---|---|
| Product family | Weldable ribbed reinforcing steel for concrete |
| British Standard | BS 4449:2005+A3:2016 |
| Grade selection | B500B (Class B) / B500C (Class C) |
| Characteristic yield strength | 500 MPa, both grades |
| Typical nominal diameter references | Ø6, 8, 10, 12, 16, 20, 25, 32, 40, 50 mm; confirm actual availability |
| Product forms | Straight bars / coils / decoiled product, subject to grade and size |
| Commercial lengths | As specified in the purchase order and confirmed for supply |
| Ribbed surface | Deformed reinforcement, identification and bond geometry per applicable clauses |
| Chemical verification | Cast/product analyses, carbon equivalent (Ceq) and special exceptions |
| Tests and documents | Tensile properties, rib geometry, nominal mass, rebend, MTC and lot traceability |
| Optional processing | Cutting / bending to approved BS 8666:2020 schedule when agreed |
| Quotation basis | Grade, diameter, form, lengths, quantities, tests, destination and delivery terms |
Use the nominal mass per metre for initial purchasing estimates. Physical rolled bars have permissible tolerances and may be invoiced on an agreed weight basis.
| Nominal diameter | Nominal area (mm²) | Reference mass (kg/m) | 12 m example (kg) |
|---|---|---|---|
| Ø6 | 28.3 | 0.222 | 2.664 |
| Ø8 | 50.3 | 0.395 | 4.740 |
| Ø10 | 78.5 | 0.617 | 7.404 |
| Ø12 | 113.1 | 0.888 | 10.656 |
| Ø16 | 201.1 | 1.579 | 18.948 |
| Ø20 | 314.2 | 2.466 | 29.592 |
| Ø25 | 490.9 | 3.854 | 46.248 |
| Ø32 | 804.2 | 6.313 | 75.756 |
| Ø40 | 1,256.6 | 9.864 | 118.368 |
| Ø50 | 1,963.5 | 15.413 | 184.956 |
Nominal weight depends on bar dimensions; B500B and B500C use the same nominal size/mass basis. Grade testing and delivery are quoted separately.
Chemical and carbon-equivalent limits are important to a weldable BS 4449 rebar specification. The full standard allows defined conditions and exceptions.
Common reference limits, shown as mass percentages, apply across the BS 4449 weldable grades. Distinguish cast and product testing:
| Element | Cast analysis max. | Product analysis max. |
|---|---|---|
| Carbon (C) | 0.22% | 0.24% |
| Phosphorus (P) | 0.050% | 0.055% |
| Sulphur (S) | 0.050% | 0.055% |
| Copper (Cu) | 0.80% | 0.85% |
| Nitrogen (N) | 0.012% | 0.014% |
| Carbon equivalent (Ceq) | 0.50% | 0.52% |
Ceq = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15. Use the heat analysis or contractually required basis to check the declared carbon equivalent.
BS 4449 is a weldable material specification; it does not by itself authorize every joint design, welding process or site procedure.
A compliant purchase covers identifiable reinforcement, not just a specified yield-strength number.
Choose the form and processing workflow needed by the bar fabricator or project receiving yard.
Ordered by nominal diameter, length and piece or tonnage schedule. Bundle labels and agreed inspection records support stock handling and fabrication.
Use when the ordered diameter, grade and processing route allow coiling or decoiling. Final dimensional, ductility and inspection requirements must apply to the delivered form.
A selection guide for engineers, reinforcement fabricators and distributors sourcing steel to project specifications.
Footings and ground beams to the approved reinforcement schedule.
Longitudinal reinforcement and ties where design calls for the selected class.
Rebar assemblies for concrete floor and beam structures.
Project reinforcement subject to design authority and exposure requirements.
Repeated reinforcement sizes for scheduled precast assemblies.
Cut and bent items to approved schedules and shape codes.
Buying to BS 4449 requires accurate materials documentation as well as competitive shipment planning.
8 million MT of annual steel output across company product categories supports broader long-products procurement coordination.
1 million MT of combined regular inventory across steel categories supports quote-based stock verification; individual rebar availability is checked.
Grade, tensile properties, weldability chemistry, rib pattern, lot records and agreed MTCs are treated as purchase-order requirements.
Support for packing, documentation, loading and agreed destination handover, with lot and shipment details confirmed before dispatch.
Estimate nominal material weight by metric diameter. Use the same tool for B500B and B500C when their nominal sizes match.
Enter the nominal diameter, ordered bar length and piece count for one line item.
Each diameter is linked to a nominal kg/m reference. The total is calculated from length and piece count; the actual rolled rib height is not used as a solid round-bar diameter.
Example: Ø20 mm at 2.466 kg/m, 12 m long and 100 bars equals 2.9592 MT, displayed as 2.959 MT.
Planning estimate only. Confirm the invoicing basis, delivered weight, permissible mass deviations, length and final packing list.
Confirm grade, form, size and inspection scope before scheduling mill allocation or dispatch.
Grade-specific stock is verified by size, origin, documentation and delivery requirement, not inferred from overall inventory totals.
Submit the B500B/B500C tonnage split, bar diameter, cut length, delivery location and target date. Stock allocation or planned production can then be checked on the relevant supply route.
Company-wide regular inventory is reported as 1 million metric tons across steel categories. This figure is not a live count of British Standard reinforcement in each size.
Technical documentation must identify the actual supplied material and reflect the conformity criteria stated by the approved project specification.
Align a material purchase with the approved reinforcement fabrication instructions; processing is arranged only where technically and commercially agreed.
Plan handling and paperwork early so site teams can reconcile bundles against the project schedule.
Clear project requirements reduce material substitutions, schedule revisions and shipment mismatches.
We will confirm the technical specification, available supply route and delivery arrangement before quoting.
Use the appropriate standard and grade from the approved reinforcement design; matching yield numbers alone does not establish interchangeability.
Answers on B500B/B500C selection, nominal mass, documentation and project purchasing.
BS 4449:2005+A3:2016 is the current British material standard for weldable reinforcing steel in bar, coil and decoiled form. State its edition and the required grade in the purchase order.
Both have 500 MPa characteristic yield strength. B500B has characteristic Rm/Re ≥1.08 and Agt ≥5.0%; B500C has Rm/Re ≥1.15 and <1.35, and Agt ≥7.5%.
No automatic substitution should be made. The engineer or approval authority must review the design grade, ductility, fabrication, joining and project acceptance requirements.
It denotes the 500 MPa characteristic yield-strength class, while B and C denote different ductility classifications.
Common metric nominal diameter references include Ø6, Ø8, Ø10, Ø12, Ø16, Ø20, Ø25, Ø32, Ø40 and Ø50 mm. Confirm product-grade, diameter, form and quantity availability when requesting a quotation.
Multiply nominal kg/m by length in metres and piece count. For example, 2.466 kg/m × 12 m × 100 Ø20 bars equals 2,959.2 kg, or 2.9592 metric tons.
BS 8666:2020 covers reinforcement scheduling, cutting, dimensional notation and bending. BS 4449 governs the reinforcing steel material and its product characteristics.
No. Material chemical controls support weldability, but welding procedures, joint type and site/engineering acceptance still require an applicable approved method.
No. Any requested CARES or other certification must be checked for the actual manufacturer, product, scope and shipment. Ask for verifiable approval documents.
Depending on the contract, specify heat or lot identification, chemistry, carbon equivalent, tensile and elongation properties, bend/rebend testing, nominal mass and relevant traceability information.
Cut-length and BS 8666 bending requirements can be reviewed by enquiry. Supply and processing availability, fabrication drawings and costs are confirmed individually.
Send B500B or B500C grade, BS 4449 edition, diameter and length schedule, total quantity, processing needs, MTC/certification requirements, destination and requested delivery terms.
Send your required grade, dimensions, quantity and destination. Our team will review the inquiry.
