Sliding mobile partitions: modular rail-mounted panels
The top rail carries 80 to 150 kg/lm and requires an L/500 deflection
A sliding mobile partition is only relevant above 80 m² and 2 reconfigurations per week: below that, its structural premium (loaded rail of 80-150 kg/lm, structural engineering calculation, steel bracket) never pays off against a conventional demountable partition. For the architect, it is therefore not a standard partition product, but a structural component to be integrated from the preliminary design stage. The mobile partition divides a 120 m² room into two 60 m² spaces in less than 5 minutes, by manoeuvring suspended panels 800 to 1200 mm wide and up to 6 m high, reaching Rw 38 to 56 dB according to NF S 31-080. Kytom has deployed these partitions since 2006 in office floors, training rooms and auditoriums.
The sliding mobile partition rests on an extruded aluminium rail with a section of 100 to 160 mm, anchored to a load-bearing structure capable of carrying 80 to 150 kg per linear metre according to manufacturer specifications. A standard suspended ceiling with 600 x 600 mm tiles is never suitable: fixing is carried out on a concrete slab, IPE beam or reinforced steel framework, with an admissible deflection of less than L/500 under service load, a value compliant with DTU requirements and the Technical Assessments of the referenced manufacturers.
For the architect and the technical project manager: a package to integrate at the preliminary design stage, not in the final technical specifications. Contrary to the widespread practice of treating the mobile partition as a late fit-out package, our reading of the project is clear: the structural provision (steel bracket, slab overload, partitioned plenum) must appear in the structural works tender documents, not in the joinery package. The misalignment of the specification is the leading cause of cost overruns observed on site, with an average impact of 8 to 15 % of the package.
The structural sizing follows this logic:
- panels 800 to 1200 mm wide, up to 6 m high
- surface weight 35 to 80 kg/m² depending on the acoustic core
- thickness 85 to 110 mm for the panel excluding hardware
- an 8 m rail supporting 12 panels of 50 kg, i.e. a minimum load of 600 kg
- lateral or perpendicular storage area sized at 110 % of the deployed length
The panels incorporate a multilayer core: 32 kg/m³ mineral wool, high-density plasterboard such as heavy BA13, viscoelastic interlayer. The exterior finish (melamine, HPL laminate, wood veneer, fabric stretched over a frame, 44.2 laminated glazing) is chosen in coordination with the fit-out package. The CE marking and the manufacturer’s Technical Assessment are still required as an attachment to the tender documents.
Limit of application. The sliding mobile partition loses its value below 80 m² of surface to partition or for fewer than 2 reconfigurations per week: the structural premium (steel bracket, structural engineering calculation, loaded rail) does not pay off against a conventional demountable partition. Below this threshold, the structural premium generally does not pay off, and a conventional demountable partition remains more suitable.
The reference acoustic requirements impose an Rw of between 32 and 38 dB minimum, while professional ranges reach Rw 56 dB
Acoustic performance is the determining criterion for the architect. The requirement levels by use category in tertiary offices are set by the acoustic regulations applicable to tertiary buildings. The indicative prices below correspond to ranges observed on the French tertiary market for sliding mobile partitions, excluding installation under the structural works package.
| Use | Acoustic requirement | Product range | Indicative price excl. VAT/m² |
|---|---|---|---|
| Training room, simple separation | Rw 32 dB standard | Panel 35-45 kg/m² | 850-1000 EUR |
| Confidential meeting, executive committee | Rw >= 38 dB management | Panel 55-65 kg/m² | 1100-1300 EUR |
| HR interview, mediation | Rw 48-52 dB | Double-skin panel | 1250-1400 EUR |
| Auditorium, board of directors | Rw 55-60 dB | Triple core, automatic seals | 1400-1500 EUR |
Acceptance measurement follows the standardised laboratory protocol and the standardised in situ measurement. The laboratory/site gap (measured R’w vs catalogue Rw) is systematically unfavourable by several decibels, linked to flanking transmissions via the access floor, an unpartitioned plenum and permeable adjacent partitions. The reaction to fire requires a B-s2,d0 classification for ERP premises, justified by a test report compliant with the euroclass classification framework in force.
Kytom’s position: specify in in situ R’w, not in catalogue Rw. The profession’s accepted wisdom still specifies an acoustic requirement in the tender documents using the manufacturer’s Rw value. Our acceptance practice diverges: we recommend contracting an in situ R’w requirement reduced by 4 dB compared to the catalogue. This distinction avoids the vast majority of acceptance disputes, by forcing the adjacent package (access floor, plenum) to address flanking transmissions upstream.
Limit of application. Above a required Rw of 52 dB, the sliding mobile partition reaches its economic and technical limits: moving to Rw 56-60 dB doubles the surface weight, requires automatic seals and imposes motorisation. Above Rw 52 dB, a fixed acoustic partition rated Rw 60 dB generally proves more economical for equivalent performance; the trade-off in favour of a fixed partition is recommended unless weekly flexibility is imperative.
The operating mode is chosen on 3 thresholds: 80 kg, 3 cycles/day, 5 m
The choice of operating mode determines the lifespan of the carriages and user comfort. Three technical thresholds intersect, drawn from site practice cross-checked with the manufacturers’ Technical Assessments:
- Unit weight threshold: a panel of up to 80 kg can be operated by hand by one person. Above this, semi-automatic pneumatic assistance is recommended.
- Frequency threshold: above 3 operations per day, electric drive limits mechanical wear and significantly extends the lifespan of the bearings compared to intensive manual use.
- Height threshold: above 5 m, electric operation becomes almost mandatory for lateral stability and operator safety when handling loads at height.
The premium for the electric motor generally represents 25 to 40 % of the price of the manual version, according to the consultations carried out for this type of project. The controls incorporate a key switch, a wall selector or BMS control via the BACnet/Modbus protocol depending on the technical project manager’s specification. Acceptance includes an in situ acoustic test, a 2-hour user training session and the handover of the maintenance log providing for annual greasing of the carriages and a check of the perimeter seals every 24 months.
Limit of application. Electrification is not justified below 1 operation per day or under 4 m of panel height: in these configurations, the return on investment lengthens significantly and electronic reliability remains lower than that of a manual system.
Frequently asked questions
From what surface area does a sliding mobile partition become relevant compared to a conventional demountable partition?
Above 80 m² of surface to partition and 2 reconfigurations per week. Below that, the structural premium (loaded rail of 80-150 kg/lm, structural engineering calculation, steel bracket) generates an ROI of more than 12 years versus 5 to 7 years with frequent use.
