The Ministry of Business, Innovation & Employment talks about inconsistency in steel reinforcing mesh testing, Building & Housing Minister Nick Smith talks about strengthening the testing requirements.
Either way, they want your opinion – but quickly. The ministry called for submissions on Friday on the proposed changes to B1 structure: B1/AS1, B1/VM1, and wants feedback within 3 weeks, closing on Thursday 8 September.
The ministry said: “A number of potential issues have been raised with MBIE around the use in New Zealand of the steel reinforcing testing standard AS/NZS 4671:2001: Steel reinforcing materials, which is referenced in both B1/AS1 & B1/VM1 for grade 500E ductile welded steel mesh.
“These relate to both the content of the standard & how it is interpreted for use in New Zealand. This has resulted in inconsistent application of the standard by New Zealand testing laboratories and uncertainty over the performance of ductile steel reinforcing mesh in the New Zealand market.
“Apart from a minor amendment in 2003, the content in AS/NZS 4671 dates from the late 1990s. The ministry intends to update the acceptable solution B1/AS1 & the verification method B2/VM1, and AS/NZS 4671 will also be updated by Standards Australia & Standards NZ.
“It is proposed that the amendments to the acceptable solutions & verification methods will be published on, and have an effective date of, 7 October 2016, apart from the requirement for testing laboratories to be accredited by IANZ (International Accreditation NZ) or an ILAC (International Laboratory Accreditation Co-operation) signatory. This latter requirement would come into effect on 1 January 2017.”
Smith says more tests required
Dr Smith said: “The Government is tightening the requirements for verifying that steel mesh used in New Zealand matches up to our standards. We are increasing the number of tests required, clarifying exactly how the tests are done and requiring the tests to be undertaken by internationally accredited testing laboratories.
“There have been issues with the quality of a small amount of steel mesh, which the Commerce Commission is investigating. The updated verification standard & acceptable solution will apply to all steel mesh of grade 500E being sold in New Zealand, whether made locally or imported. This will make it absolutely clear to the industry exactly what should be tested and the standard to which that must be done. It will help ensure the product meets our 10% ductility requirements for residential buildings, and gives certainty to the public that the mesh used in new houses is fit for purpose.
“The issue that has caused concern is ductility, or the capacity of mesh to retain its strength when stretched. The rules were toughened in response to the Christchurch earthquakes, so that all new homes had to have steel mesh of 10% ductility to increase the resilience of floor slabs after a quake.
“There have been problems with suppliers meeting both the old & new standards, and disputes over how they are applied. These new requirements will better ensure consistency & compliance.
“The building industry is booming, and this is putting additional pressure on our quality assurance systems. This is one of more than 30 changes we are making to Building Code compliance documents to ensure we get both quality & quantity.”
Dr Smith said these new requirements meant additional testing capacity would be needed in New Zealand: “We currently have 2 accredited laboratories, and IANZ has additional applications being processed.”
25 April 2016: Commission lifts ‘stop’ on Euro Corp steel mesh
5 March 2016: Suppliers recheck as commission questions steel mesh, ministry not worried
8 April 2016: Steel & Tube undertakes dual mesh testing
Attribution: Ministerial & MBIE release & documents.