Standards for reinforcement

Standards relating to concrete reinforcing and prestressing steels are:

BS 4449: 2005+A3: 2016 Steel for the reinforcement of concrete weldable reinforcing steel, bar, coil and decoiled product

This standard defines three grades of reinforcement conforming to the now withdrawn BS EN 10080: B500A, B500B and B500C.  The characteristic yield strength is set at 500 MPa and the tensile properties and ductility of the three grades are described in Table 1.

Characteristic tensile properties


Yield Strength



Tensile/yield strength ratio


Total elongation at maximum force, Agt












1.15, < 1.35


a Rm/Rc characteristic is 1.02 for sizes below 8 mm

bAgt characteristic is 1.0% for sizes below 8 mm

Values of Rc specified are characteristic with p = 0.95

Values of Rm/Rc and Agt specified are characteristic with p = 0.90

Calculate the values of Rm and Rc using the nominal cross sectional area

The absolute maximum permissible value of yield strength is 650 MPa.

The three grades conform to the three recommended ductility classes in BS 1992-1-1: 2004 (Eurocode 2). It should be noted that below 8mm diameter, reinforcing steel to BS 4449 does not conform to BS EN 1992-1-1 with respect to ductility.

BS 4449: 2005 uses the term 'bar' for ribbed reinforcing steel. The terms 'rod' and 'wire' should be restricted to describe reinforcing steel in coil, or wire in reinforced concrete products.

BS 8666: 2020 Specification for scheduling, dimensioning, bending and cutting of steel reinforcement for concrete

The 2020 revision of this code involved restructuring and general updating of the 2005 edition. The 2005 edition was produced in order to conform to the anticipated implementation of EN 10080, and incorporated:

  • Shape codes available under BS EN ISO 3766: 2003. 
  • Revised notation in accordance with BS 4449: 2005  and BS EN 10080: 2005. 
  • Revisions to BS 4449: 2005 (including the omission of grade 250 reinforcement), BS 4482: 2005 and BS 4483: 2005. 
  • The provisions of EN 1992-1-1 (including the preclusion of wire to BS 4482: 2005 for use for structural purposes).  
  • Measurement of properties of decoiled material.
  • Inspection frequencies of component dimensions. 

BS EN 10080: 2005 Steel for the reinforcement of concrete, weldable, ribbed reinforcing steel 

Weldable steel for the reinforcement of concrete has become subject to the European Standard, BS EN 10080. In 2008 it had to be withdrawn as a harmonized standard because some countries legal requirements for additional properties of reinforcement were not met. However, it was implemented in the UK in late 2005 and its subsequent withdrawal has no effect on BS 4449 etc.

BS EN 10080:2005 gives no actual specification or figures; that is left to the National Standards.

BS EN 10080: 2005 Requires that technical classes should be specified by values of:

  • Re,               yield strength; 
  • Rm/Re,          Ratio of tensile strength/Yield strength, 
  • Agt,              Percentage total elongation at maximum force, 
  • Re,act/Re,nom    (where appropriate), Ratio of actual to specified value of yield strength, 
  • fatigue strength, 
  • bend performance, 
  • weldability, 
  • bond strength, 
  • tolerances and 
  • dimensions. 

It contains an informative Annex ZA, which describes how the standard may be used for the purposes of CE marking. Please note that the CE mark is not a quality mark. It merely identifies the product as conforming to the essential requirement laid down by the European Commission in their 'mandate' to CEN. CE marking is not a requirement of BS 4449:2005 and reinforcement cannot be CE marked as the harmonized standard has been withdrawn.

BS EN ISO 17660: Welding of Reinforcing Steel

This standard has two parts:

  • BS EN ISO 17660-1: 2006. Welding. Welding of reinforcing steel - Load-bearing welded joints
  • BS EN ISO 17660-2: 2006. Welding. Welding of reinforcing steel - Non load-bearing welded joints 

BS 4482: 2005 Steel wire for the reinforcement of concrete products - Specification

This standard incorporates plain, indented and ribbed wire, coiled or decoiled. Grade 250 has been incorporated. The characteristic strength of the high yield steel has been set at 500 MPa and the ductility aligned with B500A in BS 4449:2005, but no fatigue performance is specified. 

Most wire to BS 4482 is unlikely to comply with BS EN 1992-1-1. To avoid any confusion, any design to BS EN 1992-1-1:2004 should have reinforcement specified to BS 4449:2005. Similarly, any fabric used for structural purposes should be manufactured to BS 4483 using material specified to BS 4449:2005.

BS 4483: 2005 Steel fabric for the reinforcement of concrete - Specification

Apart from wrapping fabrics D49 and D98, fabric will be made from and evaluated as BS 4449:2005 material. A requirement for the strength of welded joints in BS EN 1992-1-1 has necessitated the withdrawal of A98 and B196 and has increased the diameter of transverse bars in some other designated fabric types.

BS 5896: 2012 High tensile steel wire and strand for the prestressing of concrete.  

This standard provides the requirements for uncoated high tensile strength steel wire and strand for prestressing concrete.  It can be used while prEN 10138 standards are in preparation.

BS 4486: 1980 Specification for hot rolled and hot rolled and processed high tensile alloy steel bars for the prestressing of concrete.

This British Standard specifies requirements for preferred sizes of smooth or ribbed alloy steel bars in straight lengths supplied in the hot rolled or hot rolled and processed conditions. It can be used while prEN 10138 standards are in preparation.

EN 10138 Prestressing Steel

prEN 10138 Prestressing steels is in four parts:

  • prEN 10138 Prestressing steels. Part 1 General requirements 
  • prEN 10138 Prestressing steels. Part 2 Wire 
  • prEN 10138 Prestressing steels. Part 3 Strand 
  • prEN 10138 Prestressing steels. Part 4 Bars 

These parts are currently under development.

BS 6744: 2023 Stainless steel bars – Reinforcement of concrete – Requirements and test methods.

This revision made a general update and revised the standard such that it can be used in conjunction with BS8566: 2020. The document may be used while prEN 10370 is under preparation.

prEN 10370 Steel for the reinforcement of concrete. Stainless steel

This standard is currently under development.