2018 NCC Seminars: Performance-based design

Like now to move on to one of the main components of our seminar today, and that is performance based design.

As we all know, performance based design is facilitated through the national construction code. In 2012, the ABCB commissioned a study that quantified in dollar terms, the value of regulatory reform, three particular regulatory reforms, one of which was the introduction of the 1996 performance based building code of Australia. That study estimated that performance based design had generated an annual 700 million dollar productivity gain to the industry. The study also estimated that that productivity gain could be readily doubled through the further promotion acceptance and application of performance based design.

Now, the methodology of building design using performance requirements is undertaken through what we call performance solutions, which is one pathway for achieving compliance with the NCC performance requirements. Compliance can also be achieved via deemed to satisfy solutions or a combination of either.

Each of those three pathways is independent, and each is equally valid. Some people have commented in the past that quantification of performance may not necessarily equate to the same metrics that can be derived from deemed to satisfy. There are many ways of quantifying performance. The fact that you have differences in outcomes is not significant. Either pathway is valid.

So, what is a performance solution? In essence, it's anything other than compliance with a deemed to satisfy solution. So, if you want to implement a component of building design that is other than deemed to satisfy, it becomes a performance solution, and it becomes a performance solution irrespective of the quantity of variation between the deemed to satisfy and performance solution.

While the ABCB produces the national construction code, which facilitates performance based design, the administration of performance based design is governed by specific requirements of state and territory governments.

How to develop a Performance Solution

We're now going to move on to one of the main topics of today's seminar and that is to provide information on how to develop a performance solution. The answer is simple, just follow the ABCB guide.

We've produced a guide called development of performance solutions. It looks like that. There's a copy of the four page guide in your pack, and there's a copy that's also available on our website. The guide establishes four steps in a process to develop a performance based design, a performance solution. We're going to discuss that four step process in the next few slides, and then after we've discussed the four step process, we'll apply that process to a hypothetical case study.

So, we'll learn what's required generally, and then we'll look at application of the process to a hypothetical proposal. It may be easier to follow the discussion if you retrieve the copy in your pack. Don't necessarily need it unless you want to write on it. We'll have all the information up on the screen.

So, this four step process that we're going to go through, it can be applied to any proposed performance solution. It can be applied to

Energy efficient requirements

Stair geometry

Size of window openings

Number of sanitary facilities

Anything at all

When the process is applied, it should be applied with respect to the assumed complexity of what's being proposed. If you're proposing a complex performance solution or a number of performance solutions that will interact together to produce a complex outcome, that's what our guide describes. It is comprehensive. It is thorough. It is a complete solution for an A to Z performance process. Therefore, in that context, if you have a very simple proposal, you may still be governed, or you may still need to consider the content of our guide, but apply it to a simpler degree than what's described in the document.

First step of a four step process, we need to prepare a brief. This slide shows a copy of page one of the four page document, and I don't expect anyone to be reading this. I'm going to talk to it. I'm going to break it down into bits and pieces, but the essence of this page is to prepare a brief.

So, what is a brief? A brief is a document prepared in collaboration with stakeholders that, when completed, becomes the agreed basis for the development and assessment of a proposed performance solution, the development and assessment of a proposed performance solution.

So, when this document's prepared, who should manage the preparation? Who should manage the process? Doesn't really matter who does it. Typically, a designer, the principal designer perhaps, the architect, or the approval authority of a performance solution. They may be suited to managing the preparation of the document and to nominating initial key stakeholders, and I say initial key stakeholders because the key stakeholders that start the process may not continue through the whole process, and others may be called in at a later time when it's determined that someone additional to the existing number of people is needed.

One of the key stakeholders in any performance solution will be the approval authority, and the involvement of the approval authority in step one of this process, the preparation of the brief, appears to be generally accepted as not being a conflict of interest for the purposes of legislation within each of the states and territories. Typically, it's considered that the approval authority should not be involved in a design of a building that it is going to approve or consider for approval.

So, in our four step process, because the step one is the preparation of a brief that describes what's going to be done and how it's going to be done, it's not considered to be part of the design, and therefore, the approval authority can participate in the development of the performance solution at step one, but then must not participate in the process for steps two, three, and four. The involvement of the approval authority and the development and assessment of a performance solutions is generally considered necessary to cease at the end of step one.

So, who would be our key stakeholders? Who would be the group that would consider the development, assessment of our performance solution? The selection of stakeholders typically depends on the characteristics of the building that will be the subject of the performance solutions, and the scope and the complexity of the performance solutions. We'll consider who should be stakeholders when we look at our case study, and you'll probably gain an understanding of why certain people may or may not be considered to be a key stakeholder for the purposes of this process.

So, the stakeholders are going to prepare the brief. What does it record? The information that's circled here is presented in the flowchart under step one in your guide, and we're now going to talk about this component. The content of a brief records

Data relevant to the characteristics of the building

It records data relevant to the scope of the proposals

The agreed performance requirements

The agreed assessment methods

The agreed acceptance criteria

The scope of required evidence

And the format of the final report

So, we're going to talk about what is in, what's required to be recorded under each of those headings, and then we'll have a look at our case study.

Under step two of the guide, we test the proposal. So, in step one, we've recorded all the characteristics that we think are relevant to the performance solution, the approval authority steps out of the process, we're then going to test, analyse, model, whatever word you want to use, whether or not the performance solutions will comply with the NCC.

Each proposal will require specific analysis, modeling or testing relevance to its complexity. For some particular issues, there may be generic methodologies that are used, but each of the performance solutions has to have its own testing, analysis, evaluation process. The role of the stakeholder group is to ensure that the brief describes an appropriate scope of analysis. It has to agree on what's required to demonstrate that the performance solutions will comply.

Step two, testing of the proposal, is generally carried out by respective experts. So, if your performance solution related to stair geometry, for instance, one of your key stakeholders may be an ogonomist. They will be the relevant expert, which will test or provide a means of compliance with the relevant NCC performance requirements.

So, the outcomes of step two, the outcomes of your testing method of your testing process should be documented and should be presented to the stakeholder group for review.

So, on to step three. The stakeholder group will consider the results of step two. They will collate and evaluate the results. During the ocnduct of step two, it may be necessary to undertake multiple design scenarios. What that means is that you can take the opportunity when you're testing something, if it is demonstrated not to work, to make a variation to the proposal to find out whether or not a slight variation will work. For instance, a travel distance.

If you're looking to extend travel distance, your original proposal is to extend it by 30 meters. During step two, the experts determine that's not appropriate. At that time, they might test whether 25 is appropriate, whether 20 is appropriate. They will be optional design scenarios. So, in step three, the outcomes of step two must be evaluated, and conclusions will be drawn by the stakeholders as to whether or not the outcomes achieve the acceptance criteria set out in the brief.

And then finally, after their evaluation and conclusions are drawn, the whole process is finalized by the preparation of a report, a report that demonstrates the brief was produced, testing was undertaken, the outcomes of testing were assessed, and the stakeholder group concluded that the proposal met the performance requirements of the NCC.

So, that's an outline of the four step process, and you'll note that in step one, one of the issues that we addressed was a need to agree on appropriate assessment methods. To assess a performance solution, you need to accept that while the deemed to satisfy provision of the NCC are deemed by regulators to comply with performance requirements, performance solutions must be assessed specifically to determine whether they comply. So, deemed to satisfy are taken as complying. Performance solutions must be specifically assessed, and the NCC describes how these performance solutions must be assessed.

In volume one, clauses AO3B and AO5 will describe how performance solutions are to be assessed. In volume two, clauses 103B and 105 will describe how performance solutions are to be assessed and equally, volume three has similar provisions.

Volume one as an example, volume AO103B says a performance solution will only comply with the NCC when the assessment methods used satisfactorily demonstrate compliance with the performance requirements.

The other provision that will relate to the assessment methods for performance solution are in AO5, and AO5 includes four assessment methods of which any combination of them can be used to determine that a performance solution or a deemed to satisfy solution complies with the performance requirements as appropriate. First form that's acceptable is evidence, evidence to support that the use of a material or product form of construction of design meets a performance requirement or a deemed to satisfy provision, as described in A 2.2.

We spoke earlier this morning about the evidence of suitability handbook that the ABC has produced to assist in the application of clause A 2.1 and A 2.2. So, the second assessment method described in AO5 relates to verification methods. The term verification methods is in italics, and therefore it's a defined term within the NCC, and it refers to verification methods that appear in the NCC or other such verification methods as the appropriate authority accepts for determining compliance with the performance requirements.

So, you can use other verification methods than those included in the NCC. The third assessment method listed in AO5 refers to expert judgment. Once again, the term's written in italics, and it's defined in the NCC, and basically, it's a provision or a methodology that relates to an assessment undertaken by an expert, suitably qualified expert. The fourth assessment method is to compare the performance of the performance solution with that of a deemed to satisfy provision.

So, the assessment method is a matter of comparing the outcome of the application of the deemed to satisfy solution to the outcome of the application of the performance solution, and providing a suitable comparison that's deemed to be an appropriate assessment method.

When it comes to performance solutions, there is a lot of education material on our website at the moment. This slide presents an outline of that material, and I encourage you to go to our website and have a look at the information that is available. I think you will be pleasantly surprised.