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The purpose of this technical advice note is to define a consistent mandatory approach for the verification of steel materials on NZ Transport Agency projects. This is an interim measure until a full specification has been developed and issued based on the recently released version of AS/NZS 5131 Structural steelwork – Fabrication and erection(external link), when this has been formally accepted by the Ministry of Business, Innovation and Employment.

It is critical that steel components are adequately verified to ensure that they comply with the specified standards. Many projects have instituted appropriate measures to address the risk of counterfeit mill certificates, independent laboratory test certificates, and shipping documents being issued for steel components that may subsequently fail during erection or in service. However, there have been inconsistencies in the approach across previous Agency projects.

Mandatory requirements

Local random verification testing shall be carried out where any one of the following applies:

1. Steel traceability requirements to AS/NZS 5131 cannot be met.
2. Reinforcing, pre-stressing and structural steel materials are not sourced from and certified by an ACRS, API, or JAS-ANZ accredited 3rd Party Certification Scheme accredited supplier. (ACRS = Australasian Certification Authority for Reinforcing and Structural Steels, API = American Petroleum Institute and JAS-ANZ = Joint Accreditation System of Australia and New Zealand).
3. Reinforcing and pre-stressing steels are not certified as having been tested to clauses B6 or B7 of AS/NZS 4671, or clauses 7 or 12 of AS/NZS 4672.2 respectively.
4. High strength bolts are not certified as complying with AS/NZS 1252.2.
5. Mill or test certificates are not endorsed by an ILAC signatory holding accreditation for the correct scope of testing to the named steel Standard of supply. (ILAC = International Laboratory Accreditation Cooperation).
6. Mill or test certificates are not able to be verified as genuine.
7. When steel materials do not perform as expected during fabrication or erection.

Where any of the above applies, local random verification testing of the chemical and mechanical properties of critical components shall be carried out on a sample from every heat or batch by an IANZ (International Accreditation New Zealand) accredited testing laboratory in accordance with the relevant standard(s). 

Depending on the criticality of the component, this may, if acceptable to the Engineer, be reduced to 10% of the heats or batches where materials have a verifiable test certificate that has been endorsed by a third party accreditation scheme signatory recognised by ILAC, but shall be increased to 100% if any non-conformance is found. Additional local testing by fabricators may still be carried out as part of their own in-house inspection test plan.  

All test certificates must be endorsed, ie they must carry the symbol of their accreditation body and/or a statement that they are accredited by a named accreditation body for the reported tests, and they must be signed by the laboratory’s authorised signatory.

IANZ and NATA (National Association of Testing Authorities) in Australia are both signatories to the ILAC MRA (Mutual Recognition Arrangement), so material that has been certified as compliant by a NATA accredited laboratory is not required to be retested by an IANZ accredited laboratory.  

Application

These requirements are applicable to all NZ Transport Agency projects whose tenders close after 30 June 2017. Their use should also be considered for other existing projects where possible. 

Further information

For further information contact the Highways and Network Operations Structures team at bridgemanual@nzta.govt.nz.

Neil Cree