Zinc cladding system upon fire-retardant wooden battens

Following the publication of the decree of August 7, 2019 (amending that of January 31, 1986), the fire regulations came back to provisions no longer authorizing combustible materials on the facade again for 4th family buildings; and for 3rd family buildings, the facade systems must either be classified at least A2-s3,d0 for each of its constituent elements and have no air gap, or demonstrate their overall effectiveness via a laboratory assessment.

In this context, in close collaboration with VM Buildings, Woodenha Industries has had the fire behavior of a concrete (or masonry) facade insulated by zinc ventilated cladding system assessed,  the zinc cladding being implemented on continuous fire-retardant wooden battens. The laboratory assessment concerns Public Access Buildings of the 1st group from R + 2, as well as residential dwellings for 3rd and 4th families, within the limits of the prescriptions relating to the regulations specific to each type of building.

The components are used in accordance with the reference documents in force, in particular:

  • specifications CSTB 3316_V2: Timber frame and thermal insulation of fitted cladding subject to a Technical Assessment or a finding of traditionality
  • specifications CSTB 3194: Metal frame and thermal insulation of the cladding reported subject to a Technical Assessment or a finding of traditionality
  • DTU 40.41: Covers with metallic elements in sheets and long sheets in zinc, chapter 7: Protection of vertical parts.

Depending on the references covered by the Laboratory Assessment, the zinc siding can have different surface treatments and finishes. These zinc sheets are non-perforated, joined together using standing seams and fixed to the fire-retardant wooden battens with standing seam tabs, staple strips or staple tabs. The battens and wooden supports are fireproofed by Woodenha Industries.

This system also benefits from a B-s2, d0 Fire reaction classification report according to NF EN 13501-1.

These two documents combined, Classification Report B-s2, d0 and Laboratory Assessment, mean that the external thermal insulation systems presented make it possible to meet the objectives of IT 249, subject to the application of provisions specified in the official document, and justify consistency of reaction to fire performance. It is therefore a facade system which can be used for buildings of 3rd family A and B, although not classified as non-combustible (A2-s3, d0).

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