my 2c on the relevant boundary question above.
Firstly a disclaimer - I don’t know the details of the building or anything of the project other than what anyone can read in the determination, but it does provide a convenient example. There is a section in the determination as attached/ below.
Using this example, there is a mid floor deck which appears to be enclosed above (by another deck), below (with a floor) and both sides, with a ranchslider recessed around 3m from the boundary and say 2m from the building face. There is a deck on the top floor with sun louvres so the deck is effectively open to the sky.
In the example of the mid floor deck, the measurement to the relevant boundary should be from the face of the building. It looks like the determination took the distance to the boundary from the ranchslider for both levels including where it is recessed.
A fire on the mid floor room can’t vent other than towards the boundary, nor can it entrain air in the side of the plume in the case of external burning where the flame temperature decreases the further from the opening. In fire terms there is no practical difference between the room inside the non fire rated glass ranchslider, and the deck outside, especially as it will not be fire sterile with furniture, BBQs etc so there will be burning combustibles in this area.
Where the deck is open above, then it can vent upwards as more of a free burning fire without compartment effects and radiation from the opening, or flames extending from the building.
Perhaps some wording something along the lines of …
The distance to the relevant boundary shall be from the face of the building where the deck or opening is recessed into the building. Where the deck is open to above to allow unrestrained fire venting, or is open on the sides and complies with the distances to boundaries as an open sided building, then the distance to the boundary shall be the closer of the glazing line or the distance of where the deck no longer complies as open sided or open topped and becomes recessed opening or room
A picture would help I suspect.