THERMALLY-broken aluminium windows and curtain-walls provide an energy- and acoustic-efficient solution for architect and engineers seeking to design ‘green’ buildings, says Alex Dantziguian of Dubai-based Technoform Middle East, which specialises in insulation solutions for windows and facades.

In ‘green’ buildings, every aspect of the building’s outer shell and inner core materials and systems must be energy saving, high performing, and maintenance free. These energy-saving aluminium systems – technically known as thermally-broken systems – address key issues relating to the efficiency of the outer shell, he says.

Dantziguian elaborates: “One of the most exposed parts of a building is the outer shell. While windows and curtains-wall offer designers the flexibility with regards to the aesthetics and colour they desire for their buildings, the challenge is how to make them perform as these translucent parts of the building are what separate the harsh external environment from the internal comfort of the occupants.

“Aluminium offers the most structurally strong and maintenance-free material for windows, doors, and curtain-walls. While standard aluminium profile sections conduct the outside heat into the inside, thermally-broken aluminium profiles create a barrier to insulate thermal transfer. “Furthermore, these energy-efficient aluminium windows also enhance the acoustic performance of the building’s façade offering the occupants more comfort in their work, study, or sleep.”

With outdoor temperatures at 40 to 45 deg C during summer, a significant amount of air-conditioning energy is lost and expense incurred in maintaining indoor temperatures at between 20 and 25 deg C, by not having thermally-broken windows or curtain-walls, he points out.

“No wonder U-value standards are becoming stricter year by year all over the globe,” he adds.

Turning to the acoustic behaviour of thermally-broken windows, he says the most important parameter is the acoustic performance of the insulating glazing (IG) unit. “The higher it is the better is the performance of the window. Since the acoustic insulating characteristic is linked to the weight, we must select the strongest material to build the frame of the window. Aluminium is certainly the better material compared to plastic or wood, since it can bear the heaviest insulating glazing units,” Dantziguian says.

Among aluminium systems, the ones that have the smallest cross-sections offer better acoustic performance. “Smaller frame dimensions means bigger glass and, therefore, (for the same above reason) a better acoustic performance. To compare certified values of different system houses properly, we must consider tests conducted using the same composition of IG unit, external dimensions and kind of opening,” he says.

The acoustic performance can be further enhanced by increasing the complexity of the thermal breakage, as can be seen by comparing different systems of the same series of products.

The diagrams below show some of the certified values achieved by Gastaldello Sistemi, Technoform’s Italian customer. These values were achieved for the same sample dimensions (1.23 m by 1.48 m) with the same IG unit (with an Rw value equal to 50 dB), the same kind of opening (one leaf, opening and vasistas) and the same aluminium shells (Euroline 60, Euroline 65, Euroline 72 EV).

“The acoustic performances were improved by using polyamide (PA) insulating strips (widths of 24 mm, 29 mm or 36 mm). Additionally, if the thermal insulation is improved using more complex PA strips and gaskets, the acoustic performance is also further enhanced (Euroline 72).

“Also, in the same series, the system Euroline 72 AS which has the leaf ‘masked’ by the frame – therefore, with a reduced frame dimension and a bigger glass – the acoustic behaviour is improved by 2 dB,” he points out. “Hence, the strength, glazing performance, cross-section dimension and thermal performance are the key drivers in the acoustic behaviour of the windows.”

Technoform Middle East, is part of the Germany-headquartered Technoform Group, a global leader in design, production and distribution of high-performance and thermal-insulating polyamide insulation strips for thermal-break aluminium frames.

“From design concept to supporting the quality control of its customers’ production, Technoform gears every element of its operation toward complete customer satisfaction,” Dantziguian says. “We deliver what the customer needs, whether it’s a product or service, when they need it, at a marketable price that helps our customers grow their businesses.”
Technoform Middle East will be at The Big 5 Show in Dubai later this year (November 21 to 24), providing an insight on how to enhance the thermal insulation or acoustic performance of window systems.

Link for the Acoustic performances certified at IFT: