As new European thermal insulation regulations for building envelopes become increasingly stricter, thermal insulation of façade components is a means of lowering the energy needs of buildings. Owens Corning went to JEC with high-energy efficiency façade panels based on composite profiles for which they were awarded the JEC Innovation Award 2013 in the Building and Construction category. Plastics went there and spoke to Arnaud Genis, President Composite Solutions Business and Dr Eric Dallies, Science & Technology Leader Composite Solutions Business, Owens Corning.
Plastics: Congratulations on your award! Can you please specify the characteristics of your prize-winning composite façade solution?
Dallies: EU member states have made a commitment to reduce consumption of primary energy by 20% by 2020. As the building sector represents 40% of the European Union’s total energy consumption, the energy performance of buildings is a domain where new solutions regarding thermal regulation are required. So we teamed up with several partners and developed a panel to increase the thermal insulation of the buildings. The profile component uses composites to replace the PA thermal breaks and part of the aluminium of the former panel solution, thereby achieving better insulation while keeping good mechanical properties.
A composite profile inside a façade panel solution
Plastics: Current façade panels consisting of an aluminium profile with polyamide thermo breakers inside will meet these regulations at the lowest level. What improvement in terms of thermal insulations does the Cofahe solution offer?
Dallies: If you continue to use those alu profile solutions with PA thermal breaks and standard insulation materials such as glass whool or insulated foam, it would result in thicker and thicker wall constructions to meet the regulations. So we made several improvements: the opaque panel consists of 55mm vacuum insulation panel combined with glass reinforced cement supported by a composite profile. The aluminium profile with PA thermal breaks were replaced by pultruded glass and high loaded unsatured vinylester resin, in this case reinforced with Xstrand H glass combined with a continuous filament mat, a standard product from Owens Corning named Unifilo. So the pultruded parts are resistant to load and wind force. A third solution is the use of Cem-Fil, a glass fibre concrete reinforcement, also a standard solution.
Plastics: You specified the market for this solution as being the new-build and renovation projects for buildings below 28m in height. Why?
Dallies: This is because for buildings below 28m, the fire regulation is on the full panel fire resistance, even if some part are not M0 certified. For higher buildings you need a M0 certification for each component, which we do not have. According to our market assessment we think that we have a potential market of 4-5 million m2 in Europe. Right now we are going through the authorisation process which will be completed soon.
Plastics: What impact on energy saving do the new façade panels have?
Dallies: Aluminium has a psi value of 2.3W/mK. With the new composite part we have a psi value of 0.85W/mK. We have significant energy savings during winter time of about 5-12%. In summer it is more difficult. When the temperature inside the building increases, the isolation prevents an easy cooldown.
Plastics: What are the costs compared to the standard solution?
Dallies: At the moment this system is still more expensive than the standard solution. This is mainly because the assembly is more expensive. A next step will be to optimise the assembly to make the whole system more cost efficient.
Plastics: How significant a role does the building sector play within the Owens Corning group?
Genis: We have a broad range of industry sectors for our glass formulas, for example, the transportation business, renewable energy, E&E and construction. In respect to quantities, construction is our largest market. In the US this market is recovering, but we are also targeting markets like Russia where our new furnace in Gous-Khroustalny, a glass reinforcements facility, is operational. Besides that, expansions in Mexico and China now are in place.
Plastics: Dr Dallies, Mr Genis – thank you very much.
The Cofahé global panel solution is the result of a partnership among key industrial players:
The Centre Scientifique et Technique du Bâtiment (CSTB)/French public body for the evaluation/certification of building solutions. They were responsible for evaluating the Cofahe solution versus technical specifications and were also the project coordinators.
The building façade panel manufacturer and installer Goyer made the façade system development and prototypes.
The glass material manufacturer Owens Corning were the drivers behind the implementation of the composite solution.
Navier Lab, Ecole Nationale des Ponts et Chaussées, ParisTech, was in charge of composite dimensioning, design and calculation.
The Agence de l’Environnement et Maîtrise de l’Énergie (Ademe)/French Agency for the Environment and Energy Management financially supported the Cofahé project.