Perforated metal? Not in this atrium.
At the TWEED office building in Brussels, Altiplan architects selected backlit chaos AIR-board® acoustic panels from Design Composite for the atrium’s internal facade.
These translucent acoustic panels offer an alternative to the originally specified perforated metal cladding.
The project-specific system combines sound absorption with a slimmer construction and indirect architectural lighting.
The project: TWEED office building in Brussels
The previous office building dated from the 1960s, and its façade was subject to heritage protection. However, preserving the existing structure proved economically and architecturally unfeasible.
The new TWEED building combines flexible office spaces with a glazed atrium and a light natural stone facade. Set-back roof levels and terraces complement the architectural concept.
In addition, the project incorporates green roofs and photovoltaic systems. The building follows passive building standards and has achieved BREEAM ‘Excellent’ certification.
The requirement: sound absorption αw 0.80 for the interior facade
The acoustic specification for the atrium required a weighted sound absorption coefficient of at least αw 0.80.
Initially, the reference construction consisted of perforated metal cladding, a 90–100 mm air cavity and 70 mm
of rock wool. However, the architects wanted a solution that would also allow indirect backlighting. This was particularly important because horizontal bands of light define the geometry of the atrium.
Backlit acoustic panels instead of perforated metal
The selected solution uses 19 mm chaos AIR-board® acoustic panels. The installed system combines the acoustic panel with an 81 mm air cavity and a 50 mm porous absorber. According to the acoustic simulation, the complete system achieves a weighted sound absorption coefficient of αw 0.85.
This exceeds the project requirement of αw 0.80. In addition, the construction is slimmer than the original perforated metal solution and allows indirect backlighting. An alternative translucent sound absorber with αw 0.40 would have required approximately 50% more absorber area to achieve the same acoustic comfort.
Lighting design with translucent acoustic panels
An initial mock-up used LED strips along the top and bottom edges of the acoustic panels. However, this resulted in uneven light distribution.The final design therefore uses a single LED strip along the bottom edge, positioned in front of a white-faced absorber. This creates a soft gradient of light while the vertical panels remain unlit. As a result, the horizontal bands of light stand out and emphasise the geometry of the atrium.
Planned economically, built for maintenance
- Panel format 2,700 × 1,440 × 19 mm: less waste at an average panel height of 720 mm
- 1 mm translucent edge: cost-efficient, not visible from a distance
- Translucent stud joint: invisible joints, perfectly flat surface
- Dismountable via EPDM inserts: LED strips can be replaced
“Delighted to have placed chaos AIR-board® acoustic absorber by Design Composite in this beautiful project.”
Marek Kisielewicz, Partner, Altiplan architects
Frequently asked questions about backlit acoustic panels
Can acoustic panels be backlit?
Yes. Translucent acoustic panels such as chaos AIR-board® acoustic can be combined with indirect LED lighting. At TWEED Brussels, the complete acoustic system achieves a simulated sound absorption coefficient of αw 0.85. This includes the panel, air cavity and additional absorber.
What are the alternatives to perforated metal acoustic cladding?
Translucent composite sandwich panels offer an alternative to traditional perforated metal cladding. In the TWEED project, the selected acoustic system provides a slimmer construction and higher simulated sound absorption than the original reference design. In addition, the panels allow indirect backlighting.
Where can backlit acoustic panels be used?
Backlit acoustic panels are suitable for atria, foyers, reception areas, offices and internal façades. They are particularly relevant for architectural projects that combine room acoustics with lighting design.
Project facts
| Project | Atrium TWEED, Brussels (Belgium) |
| Architecture | Altiplan architects |
| Material | chaos AIR-board®acoustic, 19 mm, backlit |
| Sound absorption | αw 0.85 (build-up, simulation) |
| Certification | BREEAM “Excellent”, passive house standard |
| Manufacturer | Design Composite GmbH, Niedernsill, Austria |
Your idea. Our material expertise.
Together with our customers, we develop tailored composite solutions for architecture and acoustics. Technical data and core variants are available in the AIR-board® acoustic data sheets.
Photos: sonogamma
