Placo fire-rated partitions: balancing resistance and modularity

Designing a fire-rated Placo partition in an office environment concentrates three structuring trade-offs, which are resolved at programme level and not during the execution phase.

1. Resistance versus modularity. An EI60 partition requires continuous anchoring at floor and head, doubled studs and complete sealing of penetrations. This constructive logic closes the door to rapid reconfigurations, whereas office floors experience frequent reorganisations incompatible with a generalised EI60 logic.
2. Fire-rating versus acoustics. Achieving Rw 32 dB (standard confidentiality) or Rw 38 dB (management) requires lining with 70 mm mineral wool and 2 BA13 boards per face, i.e. a total thickness of 98 to 120 mm.
3. CAPEX versus TCO. Certified demountable fire-rated systems carry an additional installation cost, but avoid demolition over a cycle of 7 to 10 years.

Kytom’s position, contrary to common practice among project management firms. The professional doxa favours the « generalised EI60 to secure the test report » rule. Our reading, based on office projects delivered since 2006, is the opposite: architectural value lies in differentiated zoning. A well-designed office floor superimposes a modular EI30 grid (inter-office partitions, meeting rooms) and a fixed EI60/EI90 core (technical rooms, stairwells, HVAC ducts). This separation, validated by the inspection office, restores a majority of the usable area to a reconfigurable zone without destructive cutting.

The three tensions intersect with the floor plan, the fire safety system (SSI) zoning and the HR projection before the tender dossier is submitted.

When the certified demountable trade-off is not justified. Below three reconfigurations scheduled over ten years, the CAPEX premium of the demountable fire-rated system is not amortised: the standard EI60 Placo partition with planned demolition remains more economical in TCO. Likewise, on a fixed technical compartmentation (server room, HVAC duct, enclosed stairwell), modularity is a false need and the standard 72/48 system remains the benchmark.

For the architect and the building inspector: what fire-rating changes for integration and DTUs

Placo fire-rating is not just a regulatory obligation, it is an architectural integration constraint that weighs on five deliverables at the SD and detailed design phases.

• Partition thickness and structural grid. An EI60 partition with Rw 38 dB acoustic lining reaches 120 mm excluding finish, versus 72 mm for a standard partition. On a 1.35 m grid, this represents a noticeable loss of usable area per bay if the thickness is not anticipated in the site plan.
• Height under plenum and DTUs. Where there is a demountable suspended ceiling, the EI partition must rise to the concrete slab (excluding validated compartmented plenum). This requires geometric coordination with HVAC, sprinkler and cable tray networks from the detailed preliminary design phase.
• Treatment of singular points. Partition heads under ribbed steel decking, connection to curtain walls, EI door reservations: each singular point must be detailed with a corresponding test report, on pain of disqualification at the final test report.
• Functional aesthetics. Exposed intumescent seals (red joints, collars) require careful setting out when the partition remains visible (open-space, circulation). Kytom offers painted or clad variants compatible with the test report.
• CE marking and product traceability. Fire-rated BA13 boards and frames carry CE marking attesting compliance with the applicable product standards. The as-built file (DOE) must reference the technical data sheets and test reports of each component, required by the Apave, Socotec or Bureau Veritas inspection offices.

For the building inspector, the challenge is to validate consistency between the architect’s detail book, the test reports relied upon and the DTUs (plasterboard works) and DTU (works with plasterboard facings). The absence of upstream validation systematically generates several days of detailed-design rework.

Four defects that invalidate the EI classification at the final test report

The audit of sites delivered by Kytom agencies brings out four recurring defects that disqualify the classification at the test report.

• Poorly sealed penetrations. Low-voltage cables, HVAC ducts, cable trays: each penetration must receive a certified fire-rated seal of the same degree as the partition (mortar, intumescent foam or collar).
• Interrupted partition heads. Where there is a demountable suspended ceiling, the partition must rise to the concrete slab, except in cases of a compartmented plenum validated by the inspection office.
• Neglected perimeter junction. The intumescent foam joint at floor and head is an integral part of the test report. A lack of sealing disqualifies the whole assembly.
• Unanticipated penetrations. Future doors or cable passages must appear on the execution drawings, on pain of destructive cutting.

Kytom produces a detailed sealing plan, validated by the inspection office before the site opens, then documented by geolocated photos zone by zone.

Limit of the photo-tracking approach. On operations in occupied sites with tight night-work schedules (fewer than five nights per zone), zone-by-zone geolocated photo traceability noticeably increases the labour ratio and is not always sustainable. In this case, Kytom switches to targeted sampling of one penetration in three validated in the presence of the inspection office, in line with Apave and Socotec audit practices.

Four-step contractualised Kytom method

The Kytom fire-rating methodology unfolds in four contractualised steps, structured around design and build.

1. Regulatory audit. Identification of the type of establishment (Labour Code or ERP), compartment zoning, EI30, EI60 or EI90 requirements per wall.
2. Mapping of penetrations. Exhaustive inventory of electrical, HVAC, plumbing and low-voltage penetrations, and selection of the sealing process suited to each interface.
3. TCO optimisation. Trade-off between standard Placo partition and certified demountable system according to the number of reconfigurations projected over ten years (observed switching threshold: three reconfigurations).
4. Inspection office validation. Transmission of the detail book, test report and sealing plan to Apave, Bureau Veritas, Socotec or Qualiconsult before the site opens, then clearance of reservations at the final test report.

This method mobilises Kytom’s four trades and relies on the network of 11 agencies in France and Spain, with a target lead time of 12 weeks between framing and delivery on standard operations.