When it comes to building a structure that is safe, sustainable and healthy for its inhabitants, there should be no room for ambiguity.
However, previous iterations of Australia’s National Construction Code (NCC) have been a little short on detail, resulting in confusion and interpretation when reading the mandatory minimum performance requirements for buildings.
This looks set to change with the release of the 2019 edition of the NCC, which includes more measurable targets to help practitioners quantify building performance.
The Code contains all the operational requirements for the construction of buildings. A building, plumbing or drainage solution must satisfy these requirements in order to be compliant.
The latest edition came into effect on 1 May; however, adoption of the Fire Safety Verification Method has been delayed to next year.
“The NCC is basically our bible for building a building,” said Elissa Fazio, Engineers Australia’s Technical Representative on the Australia Building Code Board’s Building Codes Committee.
“It’s relevant to structural engineers and architects, fire safety engineers, mechanical engineers and energy efficiency consultants to name a few. One of the risks with the code in the past is that it has been too open to interpretation.”
Setting clear targets
The latest edition of the code aims to remove ambiguity by quantifying more of the performance requirements. For example, P2.4.4(a), which pertains to natural lighting, now provides a measure of the minimum amount of natural light that must be provided to a room.
However, Neil Savery, Chief Executive of the Australian Building Codes Board (ABCB), said practitioners still have flexibility to develop innovative solutions.
“The aim is to provide practitioners with a better understanding of what the target of the performance requirement is, without prescribing the solution,” he said.
The NCC’s performance requirements may be met through either prescriptive ‘deemed-to-satisfy solutions’ or through ‘performance solutions’, which allow engineers and architects to use their professional judgment for unique situations.
However, Savery said practitioners have been discouraged from using performance solutions as they have been regarded as too subjective.
The 2019 NCC update includes direct quantification for four performance requirements and introduces 28 new verification methods.
“The verification methods are a de facto way of establishing a target without giving you a metric,” said Savery.
“That still leaves a fair bit of scope for a practitioner, but provides a much greater degree of guidance about the expectation of the performance requirement.”
Key changes to the code
Savery estimated that around 40 per cent of the requirements were now quantified, either directly or via a verification method, and ABCB’s ambition is to quantify all of the code’s requirements.
“The metrics will vary, as a disability access metric is going to be different to a structural liability metric, for instance,” he said.
“However, the board has accepted the methodology we’ve used in establishing metrics for all of the fire safety and the structural reliability performance requirements. We’ve consulted industry experts like Engineers Australia to help us determine the metrics.”
The new edition of the code includes a number of other changes. Those most relevant to engineers include changes pertaining to fire safety for residential buildings between four storeys and 25 metres, energy efficiency for commercial buildings, a range of plumbing code requirements, and consolidated and acceptable construction practices for domestic residential construction.
“There is also a new performance requirement for how to manage condensation and water vapour,” said Brett Fairweather, mechanical engineering consultant at It’s Engineered.
“There’s also an overhaul to energy efficiency provisions in Section J.
“An important thing to remember is that the code is about minimum requirements to comply,” adds Fairweather. “Performance requirements in the past have not been very specific, but now they are being quantified. That’s a good thing, but there’s still plenty of room for engineers to approach things in different ways.”
Making the code more accessible
The latest edition of the NCC is also more accessible and has been redesigned to enhance readability and navigation of content.
“The code is now much more user-friendly for its online audience,” says Fazio. “A lot of work has been put in to making it more accessible on your phone as well. You can now scroll through and filter different elements. It’s definitely moving with the times by making the actual document more accessible no matter where you are.”
Fazio adds that the inclusion of more targets and verification methods in the NCC creates an even playing field for practitioners. “How you get there in the end may vary, but at least the end game’s the same,” she says.
While the NCC sets mandatory minimum performance requirements for buildings, Fazio stresses practitioners should aim high.
“All industry groups that are involved with the construction of a building from concept to end of life, need to ensure there are better checks and balances in place to make sure that the design’s done correctly, it’s signed off properly, the occupiers are using the building in the way it’s been designed and that it’s being maintained as needed.”
