52 dB acoustic partition: guaranteed confidentiality for your executive committees and HR rooms
70/70 mm double frame: why we refuse 90 mm substitutions
A verbal leak from an HR room can cost 6 to 18 months of salary in labour tribunal compensation, and up to 4% of revenue in CNIL penalties on GDPR article 9 data. In practice, a gap of 3 to 5 dB is systematically observed between the announced laboratory performance (Rw) and the actual in situ performance (DnT,A), a phenomenon documented by acousticians and the NF EN ISO 16283 standards. It is to neutralise this gap that Kytom, founded in 2006, designs and installs high-performance 52 dB partitions that keep their promise on site: 47 to 50 dB DnT,A targeted and measured in situ at handover, delivered in 4 weeks for 20 to 50 m², between 280 and 420 euros/m² installed. Our system relies on the decoupled 70/70 mm double frame, 4 acoustic BA13 boards and 100 kg/m³ mineral wool. Here is how we secure your executive committees, HR rooms, video booths and strategic committees, and under what conditions this investment pays for itself in less than 14 months.
Our system
Our reference system combines two metal frames 70 mm apart, decoupled by a 20 mm cavity, 4 acoustic plasterboard BA13 boards (2 per side) and a high-density 100 kg/m³ mineral wool fill. The assembly reaches Rw 52 dB in the laboratory, for a total thickness of 180 mm. In the field, in situ measurements generally reveal 47 to 50 dB DnT,A, compliant with the confidentiality objectives applicable to executive spaces.
Four execution details make the difference between a partition that keeps its promise and one that loses an additional 4 dB:
- Peripheral resilient strips at the floor, ceiling and adjacent walls, to eliminate flanking transmissions.
- Acoustic BA13 boards at 12.5 kg/m² (density 30% higher than a standard board at 9.5 kg/m²).
- Flexible acrylic joints on all junctions, with mandatory visual inspection before finishing.
- Decoupled electrical boxes, installed staggered on both sides, never face to face.
We systematically require the manufacturer’s test report certifying Rw 52 dB. And we refuse substitution with a simple 90 mm frame and 4 boards, despite a cost 60 to 80 euros/m² lower. On several projects where this substitution had been approved at the detailed design phase before our involvement, the in situ DnT,A capped at 43-45 dB, below the expected executive committee confidentiality threshold. The mechanical decoupling of the two frames is the determining factor, not the cumulative mass.
Your challenges
CFO and Asset Manager: an extra cost of 140 euros/m² that pays for itself in 14 months
52 dB is not a matter of comfort, it is protection against a quantifiable contractual risk. Three situations where the extra cost of 140 to 180 euros/m² compared to 45 dB pays for itself on a single incident avoided:
- HR confidentiality (disciplinary interviews, mutually agreed terminations): a verbal leak audible from the corridor constitutes a breach of the confidentiality obligation governed by labour law. Labour tribunal compensation observed on this ground: 6 to 18 months of salary.
- Sensitive personal data (GDPR article 9: health, trade union, biometrics): the CNIL requires appropriate technical and organisational measures. An unisolated HR room may be qualified as a technical defect, with an administrative penalty up to 4% of revenue.
- M&A executive committees and strategic committees: leak of privileged information, AMF risk for listed companies.
For the Asset Manager, the 52 dB partition increases the use value of the floor for regulated tenants (lawyers, audit, M&A advisory, outsourced HR), with a prime rent of 30 to 50 euros/m²/year observed in Paris CBD and La Défense. On a typical 30 m² operation (overall budget 12,000 to 18,000 euros excl. tax), the payback through prime rent is achieved in 8 to 14 months. For the CFO, the CAPEX trade-off is therefore read as risk avoided plus asset value, never as an isolated partitioning cost.
Natural light
48 dB acoustic glazing: 80% of light transmission preserved
We frequently combine the 52 dB plaster partition with glazed modules to preserve natural light intake, a priority criterion of environmental certification approaches. Asymmetric laminated double-glazing partitions (44.2/16/66.2 mm) reach Rw 48 dB, above the minimum threshold of 39 dB required for solid partitions, i.e. 4 dB below the solid wall, while retaining 80% of light transmission.
Three technical options depending on your constraints:
- Acoustic laminated glass 44.2 or 66.2, thickness 8 to 12 mm, acoustic PVB interlayer.
- Tempered glass, reserved for areas with mechanical stress and full-height partitions over 3 m.
- Liquid crystal panels, electrically frostable in less than a second, for on-demand visual privacy.
The extra cost of liquid crystals amounts to 380 to 520 euros/m² compared to standard glazing. On several of our completed operations, the acoustic glazed module is integrated as a key component.
The limit to know: the 48 dB glazed module loses its benefit when the specifications require DnT,A greater than or equal to 48 dB over a large glazed surface (more than 50% of the wall). The weak glazed link then drops the overall performance to 44-45 dB in situ, below the NF S 31-080 threshold. For executive committees requiring DnT,A greater than or equal to 50 dB (lawyers, M&A, strategic committees), we recommend a 100% solid partition, the only coherent answer.
Budget
280 to 420 euros/m² installed, delivered in 4 weeks
The price of a high-performance 52 dB partition installed by Kytom is between 280 and 420 euros/m² excl. tax, standard finishes included: matt paint, skirting boards, flexible joints. Adding a custom 42 dB acoustic door and laminated glazed modules brings the overall price to 480-550 euros/m².
| Configuration | Price excl. tax/m² | Manufacturing lead time |
|---|---|---|
| Solid 52 dB acoustic BA13 partition | 280-340 EUR | 1 week |
| Partition + 42 dB acoustic door | 380-450 EUR | 6 weeks |
| Partition + 48 dB laminated glazing | 420-500 EUR | 4 weeks |
| Partition + liquid crystals | 700-900 EUR | 8 weeks |
For a typical 30 m² operation with an acoustic door, the overall budget stands between 12,000 and 18,000 euros excl. tax. Beyond 80 m², we apply significant economies of scale, thanks to the pooling of tooling and the optimisation of the cutting plans for the 1.20 x 2.50 m boards.
When 52 dB is not the right answer: for a standard closed office or a classic meeting room without sensitive data, the extra cost of 140 to 180 euros/m² compared to 45 dB is not justified. 45 dB covers 80% of common tertiary needs. We reserve 52 dB for premises where verbal confidentiality is contractually required: executive committees, HR, legal, strategic video booths.
Choosing the right level
38, 45 or 52 dB: which Rw for which use
We set the Rw sound reduction level on the sensitivity of the exchanges and the contractual pressure on confidentiality. Three levels structure the tertiary market today:
| Rw level | Construction system | Target use | Price excl. tax/m² |
|---|---|---|---|
| 38 dB | Standard 72/48 mm partition, 2 BA13 boards | Individual office, non-confidential meeting room | 90-130 EUR |
| 45 dB | 98/48 mm partition, 4 BA13 boards, 60 kg/m³ wool | Standard meeting room, manager’s office, partitioned open space | 180-240 EUR |
| 52 dB | Decoupled 70/70 mm double frame, 4 acoustic BA13 boards, 100 kg/m³ wool | Executive committees, HR room, legal, strategic video booths, M&A | 280-420 EUR |
At 38 dB, a normal-voice conversation remains audible from the corridor: this level covers no formalised confidentiality requirement.
At 45 dB, the voice becomes unintelligible at 2 metres in the corridor, which is sufficient for 80% of common tertiary configurations. This is our default recommendation on executive floors without a GDPR article 9 requirement.
At 52 dB, even a raised voice becomes unintelligible: it is the only level that legally secures premises subject to contractual or regulatory confidentiality. We support your choice with a usage audit during the preliminary design phase to set the right level room by room, rather than imposing a uniform standard that inflates the operation by 30 to 40%.
Method
- Usage audit and target Rw setting
We start with a room-by-room audit with your legal, HR and IT departments to identify the premises subject to a contractual confidentiality requirement (executive committees, HR, legal, video booths). We set the target Rw (38, 45 or 52 dB) on the actual sensitivity of the exchanges, never on a uniform standard. Deliverable: premises x target Rw x quantified risk avoided matrix, within 5 working days. - Detailed design and system selection
Our design office produces the partitioning plans and arbitrates between solid wall (52 dB) and laminated glazed modules (48 dB) according to your acoustic constraints, ensuring that the signal-to-noise ratio remains below the 5 dB threshold that characterises a situation of no concern for the neighbours. We require the acoustic test reports of the selected manufacturers, and we refuse any single-frame substitution that would drop the in situ DnT,A below the NF S 31-080 threshold. Deliverable: complete tender documents in 2 weeks. - Manufacturing and trade coordination
We launch the manufacturing of the custom 42 dB acoustic doors (6 weeks) and laminated glazing (4 weeks) in parallel with the site preparation. Our site managers coordinate electricians, acoustic plasterers and joiners to avoid breaks in decoupling during the fit-out phase (staggered electrical boxes, flexible joints on all junctions). - Installation and in situ quality control
Installation in 1 week for 20 to 50 m², with visual inspection of the peripheral resilient strips, the flexible joints and the decoupling of the electrical boxes before closing the boards. We photograph each critical junction for contractual traceability. - DnT,A acceptance measurement
We carry out an in situ acoustic measurement post-delivery compliant with the applicable standard protocol and we target a DnT,A between 47 and 50 dB (depending on glazed or solid configuration). In the event of a discrepancy, we rework the identified weak points (junctions, technical penetrations) at our own expense. Deliverable: measurement report and acoustic acceptance report.
