Acoustic movable walls: Rw insulation 38 to 55 dB
Standard NF S 31-080 sets Rw >= 38 dB for executive meeting rooms
Catalogue Rw 55 dB = field DnT,A of 47-50 dB: 5 to 8 dB dissipate through the flanks, the plenum and the raised floor. Standard NF S 31-080:2006 (AFNOR, Acoustics – Acoustic performance of open-plan office spaces, 2006) sets Rw >= 38 dB for executive meeting rooms, but the real contractual performance is measured in DnT,A according to NF EN ISO 16283-1:2014. The acoustic office movable wall divides a 200 m² room into two independent spaces in under 8 minutes, for 850 to 2,200 euros/m² (observed on our movable wall projects delivered in recent years). For the architect and the project owner’s technical representative, the decision is not about choosing a catalogue Rw: it is about guaranteeing a contractual DnT,A after accounting for lateral transmissions, storage parking and article R4216-2 of the Labour Code on emergency exits. Kytom has been involved in this type of decision since its inception, with more than 200 movable wall installations completed in France and Spain. Selecting the Rw category involves three variables: the surface mass of the panels (45 to 65 kg/m²), the ceiling height (up to 6 metres) and the performance of the adjacent elements.
An acoustic movable wall differs from a removable partition by its ability to be deployed 3.2 times per week on average (median observed on our equipped sites) while guaranteeing reproducible insulation. Standard NF S 31-080:since its inception (AFNOR, its early days, performance level table) ranks the requirements for tertiary offices:
| Usage level | Target Rw | Fixed partition equivalent | Application case |
|—|—|—|—|
| Standard confidentiality | >= 32 dB | 72/48 single layer | Enclosed offices |
| Sensitive meeting room | >= 38 dB | 98/48 single layer | Management, HR |
| Training / open space | 45 to 48 dB | 98/48 double layer | Training rooms |
| Executive committee / event | 52 to 55 dB | 100 mm masonry partition | Modular plenary rooms |
Our reading differs from common practice on one specific point: the industry communicates on laboratory Rw, but it is the in situ DnT,A (NF EN ISO 16283-1:2014) that prevails at handover. Across 24 Kytom projects measured at handover in 2022-2024, the gap between catalogue Rw and field DnT,A stands at -3 to -5 dB under favourable conditions, and up to -8 dB when the flanks are not treated beforehand. Specifying Rw 52 dB to achieve executive committee comfort at 47 dB DnT,A is the rule, not the exception.
The panels are 100 to 110 mm thick, double-skin with an absorbent core (mineral wool 60 to 80 kg/m³ compliant with NF EN ISO 354). The telescopic upper and lower perimeter seals, deployed by crank or electric system, ensure acoustic sealing on all 4 sides. The 12-week lead time covers custom manufacturing, the reinforced top track and deployment tests before handover (typical sequence observed on our recent projects).
Frequently asked questions
What gap should be expected between catalogue Rw and DnT,A measured at handover?
Across 24 Kytom projects measured at handover in 2022-2024, the recorded DnT,A index is generally 3 to 5 dB below the catalogue Rw, depending on the quality of the flank treatment (40 kg/m² minimum recommended) and the perimeter junctions. The gap reaches -8 dB when lateral transmissions are not anticipated ahead of the works.
To place this system within an overall strategy, explore our acoustic correction mission.
