4 Questions Certifiers should be asking about the Cold-formed Steel Framing Industry

The construction industry relies heavily on the quality of its materials to ensure buildings are safe, durable, and fit for purpose. However, recent findings from a 15-month investigation by Rondo have uncovered alarming concerns about the use of substandard imported steel products. This investigation published by Rondo, which included six rounds of rigorous independent laboratory testing, shines a light on the risks posed by using materials that fail to meet the necessary standards.

So, what are the 4 questions?

1. What is the "ACTUAL" BMT 

Base Metal Thickness (BMT) of steel products, which represents the thickness of the steel material before the application of any coatings or treatments. This measurement is crucial as it determines the steel's strength, structural integrity, and suitability for specific applications. Some imported wall and ceiling products that we investigated failed to meet AS/NZS 4600 standards, which require cold-formed steel to be at least 95% of the designed base metal thickness. Our testing and an importer’s own published test data revealed some imported steel wall and ceiling components ranged between 85% to 94% of their specified Base Metal Thickness (BMT).

Some imported wall and ceiling products examined during our investigation failed to comply with AS/NZS 4600 standards CL 1.5.1.5, which mandate that cold-formed steel must be at least 95% of the specified base metal thickness (BMT). Both our independent testing and an importer’s published test data revealed discrepancies, with some imported steel components measuring only 85% to 94% of their specified BMT.

For example, certain products labeled as 0.50 BMT were found to have stud and track components measuring between 0.46 and 0.47 BMT, while furring channels measured between 0.45 and 0.46 BMT. Additionally, one importer’s product catalogue listed a steel stud at 0.50 BMT and track at 0.55 BMT; however, their own test data indicated actual measurements of 0.468 BMT and 0.484 BMT, respectively. These findings highlight significant inconsistencies that raise concerns about the structural adequacy and reliability of these imported materials.
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2. What is the "REAL" Zinc Coating

Zinc coatings play a pivotal role in safeguarding the steel against corrosion, as they act as a sacrificial barrier to ensure a longer-lasting product. In some cases, importers may source steel from overseas with a thinner zinc coating as a way of reducing costs, which impacts the protection against corrosion and deterioration of the steel.

The Australian Standards for Suspended Ceilings AS2785:2020 recommend in clause F.4 that steel coating protection for all ceilings inside the building envelope that are more than 300m from breaking surf should be a minimum of Z180, and for ceilings outside the building envelope, a minimum steel coating of Z275 should be used in areas more than 1km from salt water. AS1397 Cl 3.3.2 Table 3.1 explains the minimum requirement.

A lower zinc coating can lead to corrosion because the thickness of the zinc coating directly affects how long it will last. The component with the thinnest zinc coating will be the first to corrode. So check with the manufacturer on the exact coating in g/m².

3. What FIRE Report do you have to comply with NCC C2D9?

It is essential that steel products used in walls and ceilings with fire-rated requirements fully comply with the National Construction Code (NCC) Specification C2D9. This ensures that the materials meet the necessary safety standards when used in conjunction with plasterboard for fire resistance level (FRL) and provide adequate protection in case of a fire.

Both Knauf and CSR fire reports specify Rondo steel in their fire-tested systems to comply with NCC Specification C2D9. Their fire-tested systems are unique to Rondo product, with our investigation revealing differences in steel base metal thickness, shape, and manufacturing tolerances between Rondo and the imported products we tested. For other steel manufacturers, fire tests in accordance with AS1530.4:2014 is required to confirm those steel has been tested and have evidence of suitability to confirm its FRL performance.

4. What Structural Test Report do you have to comply with NCC Specification 6?

The National Construction Code (NCC) requires greater levels of abuse and impact resistance in several critical areas (such as fire-resisting walls and lift shafts) to ensure the safety of the property and its occupants. Specification 6 C6 in the NCC 2022 describes structural tests to be applied to and criteria to be satisfied by a wall system of lightweight construction. These tests include:

• Material tests — The methods specified for the constituent materials of the construction of the standards adopted by reference in the NCC.
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• Resistance to static pressure — The provisions for testing walls under transverse load in ASTM E72-15.
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• Resistance to impact — The soft body impact test in ASTM E695-03.
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• Resistance to surface indentation — The test for resistance to surface indentation, which involves a steel ball of 10mm diameter with a load of 150N placed on the surface of an undamaged test sample for five minutes, and the impression of the ball on the surface measured after it is removed. To be compliant, the wall system or the specimen of it must fulfil the criteria in Clause S6C11.

Conclusion

To ensure a compliant lightweight system is being installed properly, and to prevent the possibility of reputational damage, harm and litigation, it is important to ensure:

• Architects are confident on the product/system they specified have test reports to confirm evidence of suitability in accordance with the NCC
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• Building certifier/surveyor who are requesting for test reports from whoever that purchased the products from
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• Contractors are installing trusted brands with the support of manufacturer's test reports
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• Builder to confirm whoever subcontractor they employed are building in accordance with NCC and Australian Standards.
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Ensuring safer building standards requires a collective effort from all stakeholders in the construction industry. Together with manufacturers, architects, builders, contractors, and building certifiers must take responsibility for verifying the quality of materials by actively requesting and reviewing test reports. By prioritizing compliance with Australian standards, these professionals can mitigate risks associated with substandard or non-compliant products. This collaborative approach not only enhances the structural integrity of projects but also protects the safety and trust of end users. When everyone fulfills their role in upholding quality assurance, the industry moves closer to creating buildings that are durable, reliable, and fit for purpose.

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