Is Dincel Wall a DTS Solution?

The Short Answer: It depends… Keep reading ??

What is Dincel Wall?

Let us first find out what is Dincel Wall. So Dincel Structural Walling system is a permanent polymer formwork for re-enforced walls and columns, filled with ready mixed concrete.

The Question:

The Question is, do you require a Performance Solution when using Dincel Wall system in your building? Or is it a Deemed To Satisfy (DTS) Solution?

This article is discussing how to answer this question in detail. First, we must differentiate if the building that we want to use Dincel Walls for is considered ‘residential’ to which Volume 2 of the Building Code of Australia (BCA) applies? Or ‘commercial’ to which Volume 1 of the Building Code of Australia applies.

According to Code Mark Certificate CM20242, dated 16 June 2023,

• Volume 1 Applies,
• Volume 2 of the BCA is not applicable to this type of walling system!

Volume 1 of the NCC

What does the code mark certificate mean for Volume 1? Does it mean that this code mark certificate can be relied upon to demonstrate compliance with performance requirements of the NCC under Volume 1, without the need to go through the performance solution process?

Given that the National Construction Code (NCC) is a performance-based code, according to A2G1 of the NCC.

As such, compliance with the NCC can be achieved by complying with

A.????? Performance Solution; or

B.????? Deemed-to-Satisfy Solution; or

C.????? A combination of both solutions

In Appendix B, on page 6 of the Code Mark Certificate outlines the evaluation methods used. Method 1 (Spread of Fire assessment) lists that it has been taken to comply with A2G2(2)(a). Which is a reference to ‘Evidence of Suitability’.

Although there are 2 types of ‘Evidence of Suitability’ that can be applied:

• ‘Evidence of Suitability’ for a Performance Solution under A2G2(2)(a).
• ‘Evidence of Suitability’ for Deemed To Satisfy Solution under A2G3(2)(a).

This is illustrated in the diagram below from ABCB website that have been marked up to demonstrate the point graphically.

Deduction

-??The Code Mark Certificate is referring to A2G2(2)(a).

-??This is known as ‘Evidence of Suitability’ which is one of the methods of demonstrating compliance with the Performance Requirements of the NCC.

-??This method is used as part of a ‘Performance Solution’.

-??This means you would require a Performance Solution where Dincel-Walls are used.? ????

The Groves/Wynn-Jones report is more comprehensive and appropriate for the CodeMark Certificate and Volume 1. This can be obtained from their website or by submitting a written request.

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How Performance Solution works (A2G2)

Performance Solution is obtained by demonstrating that it either satisfies all applicable Performance Requirements or is at least equivalent to the DTS provisions that are deemed to be satisfied.

Through one or a combination of the following Assessment Methods, it must be demonstrated that a Performance Solution complies with the relevant Performance Requirements:

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1.?????? Evidence of suitability in accordance with Part A5 demonstrating that a material, or design meets the applicable Performance Requirement.

2.?????? Verification method that incorporates the following:

a.?????? The verification methods listed in the NCC.

b.?????? Other verification methods?approved by the appropriate authority.

3.?????? Expert Judgment, which is a determination made by an experienced professional.

4.?????? Comparison with the Deemed-to-Satisfy Provisions, demonstrating that the solution is equal or exceeds DTS requirements.?

Now, let us look at Volume 2.

Volume 2 of the NCC (N/A)

What does the code mark certificate mean for Volume 2? Does that mean that Dincel Wall is not a DTS Solution under Vol.2? meaning Dincel walls cannot be used for Class 1 buildings?

Or simply this is not required to be tested as it is widely known and used as an acceptable DTS Solution under NCC Vol.2 to the point that it does not even need to be certified!

Well, the Warrington Fire Report that was relied upon states that Dincel wall system “when tested to AS1530.4 can demonstrate compliance with DTS provisions of the NCC”.

Now comes the following question:

The Pressing Question?

Just tell me in simple English, does the Dincel wall system meet the DTS requirement of the NCC for Volume 2 or not?

Well, I recon the answer to this question is as follows:

To make such statement, it means that the wall meets the 3 required FRL values. (Structural Adequacy/ Integrity / Insulation).

In terms of Integrity / Insulation, they do comply and can be met and measured. However, with regards to Structural Adequacy, this must be certified by a structural engineer. The reason for this is because this value cannot be measured or tested for. But why?

Because (from my perspective) although the AS 1530.4 testing is a full panel test, it has a height limit of just above 3m. Therefore, if the tested walls exceed these parameters of the test. As such, this first value of the FRL which is the ‘Structural Adequacy’ must be provided by the structural engineer of the project to ensure that it meets the level of structural adequacy required for the project. So, it is a project-based assessment and determination.

In my humble opinion and based on my own research and discussions and consultations with other building professionals including from Dincel Wall Company itself, this is the reason why the Warrington Fire Report was cautiously worded as such, stating “can demonstrate compliance” or “Could meet the performance requirements” & “can comply with the acceptable construction provisions of the NCC” etc.?

Result:

Up on review of relevant testing reports and certification depigmentation and enquiries with the technical team of Dincel Structural Walling it was understood that laboratories have limitations in regard to their testing equipment. For example, when conducting an AS 1530.4 test at CSIRO, the maximum vertical load that their equipment can apply is 800 kN (over a 3 metre length of wall). This equates to 267 kN/m, which in real life structural engineering terms is not a significant load. This may be equivalent to a wall supporting only 3 or 4 floors above.

In addition to the load limitation, there is a height limitation. The height of the wall tested is typically max. 3 metres.

Therefore, what they are highlighting is that test results can only be relied on when within the limitations which the testing is carried out to. In other words, the maximum load on the wall must not exceed the load which it was tested for, and the maximum height of the wall must not exceed the height it was tested as.

Therefore, a much more flexible approach for concrete walls is to design to AS 3600 (Concrete Structures Standard).

155 Dincel = 155mm – 2.5mm thick external skin – 2.5mm thick external skin = 150mm thick concrete.

Therefore, 155 Dincel Wall can be designed as 150mm thick concrete for axial compression and for fire design to AS 3600.

This design approach is confirmed by the certification from the University of Technology Sydney (screenshot below).

Communication with Technical Manager from Dincel Structural Walling

When asked, Bobbee Phung the Technical Manager from Dincel Structural Walling, kindly responded with his email below confirming that the structural adequacy of Dincel wall provided that the certain design engineering principles are adopted by the designer, the It would be deemed compliant with B1.1(b) and B1.4(b)(i) from Vol. 1 and 3.0.4(d) from Vol. 2 of the NCC.? So long as they are within those parameters and limits of the test.

Anything outside those parameters must be certified by structural engineer to satisfy the ‘structural adequacy’ which is the first component of the FRL.??

Below is part of his detailed email:

I have attached the two certificates most certifiers ask for Class 1 buildings and a picture inside a Dincel concrete wall.

Volume 2 of the NCC (i.e Class 1 buildings) - P2.1.1 – Structural Stability and Resistance

Please firstly find the?attached?photo showing the inside of a typical Dincel concrete wall. Dincel structural walling complies with?3.0.4 (d)?as a form of acceptable construction, as certified by UTS (see?attached?certificate).

Dincel is simply a formwork material and the concrete on the inside is designed by the projects structural engineer to AS3600 (just like it would be with a conventional concrete wall). The structural engineer for the project typically provides a design certificate for the whole structure, inclusive of the Dincel concrete walls, to satisfy P2.1.1.

Conclusion:

Therefore, the last 2 numbers of the FRL (i.e. integrity and insulation) is essentially provided by the concrete thickness alone. The below provides a breakdown of the insulation and integrity values which is achieved by the different Dincel wall thicknesses in accordance with AS 3600:

• 110mm thick Dincel Wall = Greater than 100mm thick concrete, which provides 90 minutes in accordance with AS 3600
• 155mm thick Dincel Wall = 150mm thick concrete, which provides 180 minutes in accordance with AS 3600
• 200mm thick Dincel Wall = Greater than 175mm thick concrete, which provides 240 minutes in accordance with AS 3600
• 275mm thick Dincel Wall = Greater than 175mm thick concrete, which provides 240 minutes in accordance with AS 3600

It is the first number of the FRL (structural adequacy) which becomes project-specific for any concrete wall. This depends on the height of the wall, concrete strength, wall thickness, load and eccentricity on the wall, etc.

Yes, there is the ability to test against AS 1530.4, however there are limitations from this test to be mindful of. For example, the wall height in the test is 3 metres.

Also, the maximum load applied on the wall being tested is limited by the capacity of the laboratory equipment. The maximum load applied by the laboratory is 800kN over the 3m long element. This equates to 267 kN/m.

This is maybe good for a wall supporting only 4 or so floor levels above. Therefore, rather than relying solely on a test result to AS 1530.4 (which comes with limitations in regard to the structural adequacy component), structural engineers always prefer to have the walls designed to AS 3600 with all the project-specific variables in consideration. This is the safest approach.?

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The short answer to the following question:

Does the Dincel wall meet the DTS requirement of the NCC for Volume 2 or not?

Yes, it does, so long as it is designed and certified by structural engineer in accordance with AS 3600.

Now, just to throw another spanner in the works:

How does Dincell meets the new NCC -2022 requirement regarding H4O7 condensation and water vapor management?

Haha, that's a discussion for another time altogether ??

Are you now more confused? ??

You can either lodge a formal complaint about me or share your thoughts, experiences, and feedback. I would love to hear from experts.

Disclaimer

This article is not to be taken out of context. It is general in nature and does not relate to any particular site. You are strongly advised to seek your independent town planning or a legal advice for your site and not to rely on the opinion of this article or any comments within.

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Regards

Firas Naji

04 February 2024