The 10-storey building will comprise 35,000 sqm of gross floor area. It is owned by the Catholic Church Endowment Society and SA Water will be the anchor tenant. The project team includes Hassell as architects, Hansen Yunken as design and construct contractor and Cundall as ESD consultants.
From the initial design concept, David Clark, director at Cundall, says environmental initiatives were driven by a strong ESD brief from SA Water. But there were some difficulties with carrying out the objectives due to the large floor areas on each level. Also, integrating a laboratory into a commercial building was problematic.
One of the main problems to overcome was the building fabric. A fritted western veil was placed on the front of the building skin to reduce solar loads on the western façade. The veil is set around 1.5m off the west face of the building. Underneath is a conventional façade with a spandrel and core double glazing.
“There are actually two ways the veil works. First of all, we’ve got horizontal sun shading that’s formed by the grated walkways which support the veil. Then the veil is fritted, so it’s 50 per cent ceramic dots. This reduces the amount of direct sunlight coming in and as that glass heats up, there’s an air gap between the veil and the building façade so the hot air rises up. So you’re reducing the amount of heat that enters through the façade,” Clark says.
The idea for the veil came from Europe, and although the concept isn’t new, Clark says he isn’t aware of other projects in Australia which has used a similar technique. “It’s just adapting the concept of ventilated facades. Often you can have a façade that has an air gap. In Europe, they close it up in the winter so it retains heat and in the summer you open it up so it ventilates,” he says.
But in the Adelaide climate, Clark says there wasn’t a large benefit in closing it up in the winter. He says, “It creates something that is aesthetically interesting on the face of the building rather than just looking like a glass box. At the same time, it reduces the solar load while still allowing you the full views out of the building.
“Working out what we were going to do with that façade was a critical part of the project and it is the face onto Victoria Square. If we just put on a curtain wall with a bit of shading on it, it would have looked bad. It does create a bit of interest. We drove the concept of the double façade — this concept of a ventilated façade — which eventually became the veil.”
Cundall placed performance glazing on the other three facades. Full height glass was placed on the north and south facades and spandrels were placed on the east and west facades. By limiting the amount of glass in the building and putting in spandrels, the heat load on the building was also reduced.
“On the south we didn’t have to worry too much about solar issues so we put some vertical fins in there to cut out the late afternoon sun. The north view is the easiest façade to shade because you just put a horizontal overhang on to cut out the majority of the summer sun,” Clark says.
Inside, Cundall has also veered away from standard finishes. An ehtyl tetra fluro ethylene (ETFE) roof which runs over the full height central atrium to allow natural light in. It is two sheets of thin plastic which has very low pressure air pumping to make a pillow, creating a clear plastic aspect and can be moulded into different forms, such as bubbles.
It also installed an underfloor air ventilation system. Instead of pushing air in from the ceiling like conventional buildings, the air is distributed through an underfloor plenum on a raised floor.
“You’ve got circular grills in the floor that then let the air in so that you can move these around the same way you can move carpet tiles round. So you reconfigure where the vents are to suit fitouts just by picking them up. It gives individuals in the building a degree of control over their local environment,” Clark says. There is also a seal around the perimeter which provides air.
Underfloor systems have also been used in Council House 2 in Melbourne and Clark says it is common in Europe. The benefit is cabling is in the floor, so there is no need to run cabling in the ceiling. Clark says, “It also uses 100 per cent outside air, so the air comes in at the lower level. It comes up, takes the hot air up into the ceiling and out. So you don’t get this mixing of the air that you do in standard buildings.”
Due to the underfloor system, Cundall was able to leave some roof areas exposed. It reduced suspended ceilings by 25 per cent by exposing the concrete beams and used the gaps in the ceiling as the return air path instead of ceiling grilles.
Clark says, “I think it adds a bit of interest rather than having a flat ceiling all the way across. It means we don’t have to put any return air grills into the ceiling because the return air goes into the ceiling plenum and it just goes up between the gap and the band beam in the ceiling.
“The building does lots of basic things well, rather than using new or untried technologies.”
The building is due for completion in late 2008.
