The standards for prestressing steel are:

BS 5896 Specification for high tensile steel wire and strand for the prestressing of concrete gives the requirements for steel wire and 7-wire strand.

BS 4486 Specification for hot rolled and hot rolled and processes high tensile alloy steel bars for the prestressing of concrete gives th requirements for preferred sizes of bars, with two nominal strength levels (835 and 1080 N/mm2).

Test methods to determine the properties of steel sheaths for tendons are covered by BS EN 524 Steel strip sheaths for prestressing tendons: test methods.

Note that these Standards are in the process of being replaced by BS EN ISO 15630, Steel for the reinforcement and prestressing of concrete.