Glazing into the Future of Australia’s Building Codes.
Abanoub Mina, JHA Consulting Engineers Intern.
Into the Real World
While undertaking my university degree, I’d have to learn many formulas, rules and principles. Using these skills, I attempted to gradually decipher the Building Code of Australia (BCA). Every section was further broken down into smaller sections which I found quite overwhelming and confusing at times. However, I did not let this affect my confidence.
I then broke down each section even further into smaller sections and analysed them to the best of my ability, and when I could not understand something I reached out to my team. My colleagues generously took the time to help me understand the codes in further depth, which I deem to be very important in any field of work.
There were many other challenges which I faced, including classifications of buildings, glazing values, performance requirements, verification methods and specifications.
However, I started to slowly feel that I was grasping many concepts and identifying their connection to other sections in the BCA. I felt that I had support when I needed it and that this wasn’t as daunting of a task as I initially thought.
I felt that I had support from my colleagues when I needed it, and the task of understanding the codes was not as daunting as I initially thought.
Building Fabric and Glazing Requirements
NCC 2016 vs NCC 2019
Looking at the current building Codes and comparing it with the new upcoming Codes, it is quite clear what direction the board aims to take. In the new Codes, they have combined the building fabric and glazing into one assessment as a whole, whereas in the past they were considered as separate elements.
In order to calculate whether the facade complies or not, the new codes give us two methods of assessment:
METHOD 1
This method takes into consideration the total wall area, total glazing area, SHGC value and shading multiplier to calculate the Façade Solar Admittance (FSA) Value on each façade. The façade must perform below the maximum specified FSA to comply. Additionally, the U-Value of the façade is essential which uses the total wall area, total glazing area, U-Value of the glazing and the U-Value of the wall.
Simply, this means that EACH façade must perform according to a certain standard which is also highly dependent on the buildings climate zone and class.
Figure 1: Factors effecting Method 1
METHOD 2
This method takes into consideration everything from Method 1, but uses a few more factors such as the façade direction, to determine whether it complies or not. An Air-Conditioning Energy Value is then calculated for each façade and is summed up to give a value for the whole storey. If the actual calculated results are below the maximum value allowed, then the storey itself complies.
Similarly, the U-Value is calculated as an average of the whole storey and must be below a certain standard to comply.
Figure 2: Influencing façade factors
In summary, Method 1 is dependent on each façade performing to a certain standard, whereas Method 2 is dependent on the whole storey complying with a certain standard.
Key Findings
SHGC Comparison
Figure 3: Showing more stringent 2019 codes
As I further studied the Codes, it was beneficial to present my findings to my ESD (Environmentally Sustainable Design) colleagues. I was confident in my results but I did find it a little nerve wracking when I knew that they would have a lot more experience in the field than I did. However, after the presentation I was quite satisfied with my overall performance and did receive constructive feedback on my findings.
The presentation allowed us as a team to grow in our knowledge in the field as well as gather what direction the future Codes are taking. We concluded that the shading and wall-glazing percentage greatly influences the compliance of a building and that energy consumption would be reduced.
- The overall U-Value and SHGC values are more stringent on the new BCA as in Figure 3
- The BCA wants more shading or better glazing to comply compared to 2016
- Method 2 MAY comply even if Method 1 does not. Method 2 will always comply if Method 1 does comply
Why It’s Important?
The new Codes have proven to be stricter in comparison to the 2016 version, which does impact multiple people such as engineers, architects and the occupants.
How does it affect engineers and architects?
Reduced Energy Consumption through windows and walls
Reduced costs of HVAC systems
Higher demand on more thermally efficient windows
May affect the aesthetics of the buildings, making the building look less modern
How does it affect the occupants/clients?
May increase the costs required for glazing
Reduced costs for HVAC systems
May affect how the occupants feel
– Less glazing results in darker spaces
– May result in less open space, making the occupant feel more enclosed
The new Codes have proved to be stricter, comparative to the 2016 standards, which have multiple effects on engineers, architects and occupants. These effects are overall quite beneficial in reducing the overall energy consumption for the building; however, they may increase construction costs. This is a great step for the future as this will benefit the environment and it will doubtlessly assist in the battle of global warming.
The NCC Codes seemed quiet complex initially, but by being exposed to them, the support of my colleagues and taking the time to interpret them, my knowledge naturally grew and the codes became much simpler.
