Australia's Leading Range of Thermally Broken Aluminium Windows and Doors
Australia's Leading Range of Thermally Broken Aluminium Windows and Doors
Understanding Thermal Break Technology
Over the past five years an increasing number of window and door manufacturers within Australia have added thermally broken aluminum window and door systems to their product portfolio. Growing awareness of and demand for energy efficient building materials has driven product development in this area, resulting in an offering of window and door systems that deliver significant improvements in thermal efficiency and insulation properties.
Within Australia thermally broken aluminium window systems typically utilise one of two technologies to achieve the desired outcome of minimising heat transfer through the aluminium frame: pouring and de-bridging; or strut and spacer otherwise known as extrusion zipping.
1. Pouring and de-bridging
In thermally broken window systems using pour and de-bridge technology the window frame is first extruded as a single piece incorporating a hollow trough in the center. This hollow trough is then filled with a plastic that hardens to form an intermediate piece.
The connecting piece of aluminium is milled away leaving only the injected plastic to join the two halves of aluminium. Functionally the resulting piece is cut, mitred and assembled like a simple aluminium extrusion. Thermally the plastic slows the heat flow between the inside and the outside.
2. Extrusion zipping
In thermally broken window systems using extrusion zipping/ strut and spacer technology, individual extrusions are designed and extruded for the interior and exterior elements of the aluminium frame. These profiles are then joined using a number of polyamide strips, carefully positioned to maximise the insulation properties of the window. The strips are knurled and clamped between the interior and exterior aluminum elements and a machine is used to 'zip' the strips to the aluminium, creating a single profile with the same strength and expansion properties as a traditional aluminium window frame ensuring long-term functionality and durability.
Architectural Window Systems (AWS) developed a thermally broken range of aluminium windows and doors in 2008. The initial product release included sliding door, bi-fold door, hinged door and awning window systems. Since then the range has continued to expand and now includes a comprehensive offering of CentreGLAZE™ and FrontGLAZE™ framing in 100mm and 150mm platforms, along with compatible door systems for hinged, pivot, bi-fold or sliding installations.
"We've worked hard to make sure we can offer architects and designers a full and complete range of thermally broken systems for their projects, which will deliver excellent performance outcomes," comments AWS Designer Mark McCleary.
McCleary cites one of the major challenges in developing a thermally broken window system was ensuring the size of the profiles was consistent with that of traditional non-thermally broken framing. "In Australia, architects and builders commonly work with 100mm and 150mm framing platforms. When you are incorporating a thermal break into the system you need to ensure the break is wide enough to give the insulation improvements you're looking for, without making the profiles overly large or inconsistent with market expectations.
"We chose to use an extrusion zipping method to achieve our thermal break; this method allows you to create a true, wide break in the aluminium to maximise the thermal performance. The polyamide strips that provide the insulation are very stable and have similar strength and expansion properties as aluminium to ensure the finished thermally broken profiles are highly stable, consistent and strong. An added bonus with this method is the ability to offer dual colour extrusions - one colour inside, one colour outside -something previously unavailable to the Australian market, which really adds some flexibility for architects.
"When architects choose ThermalHEART™ they can work with the extrusions like they would any other commercial framing; it's proportionally the same. Our ThermalHEART™ systems have the same strength, durability and expansion properties as non-thermally broken framing, the systems are easy to specify, they are l00 per cent Australian designed to suit the Australian climate and market, and they solve many problems associated with Section J compliance," says McCleary.
