FIBRANskin FIRE SHIELD | Breathable membrane for pitched tiled roofs with fire-retardant properties

FIBRANskin FIRE SHIELD is a breathable waterproofing underlay membrane, manufactured in accordance with EN 13859-2:2010, with a reaction to fire classification of B-s1,d0 in accordance with EN 13501-1. It combines very low water vapour diffusion resistance (Sd = 0.015 m) with W1-class watertightness and a water column of 1.4 m — it allows moisture to escape outwards whilst preventing water from entering. Mass 68 g/m², tensile strength 275 N/50 mm in both directions, retaining ~82% of its strength after artificial UV and heat ageing. Operates from -40 °C to +100 °C and is airtight. It is installed on the cold side, over the thermal insulation, on ventilated façades and pitched tiled roofs. Roll size: 1.50 × 50 m (75 m²).

The ARGYNET View

FIRE SHIELD is purchased for one reason: its B-s1,d0 classification. And that is precisely the detail the specifier needs to know before including it in the technical specification.

The footnote in the official TDS is categorical: the B-s1,d0 classification applies when the membrane is installed on stone wool or mineral fibre boards. When installed on timber, the same membrane is classified as D-s2,d2.

This is not a technicality — it is simply how EN 13501-1 works. The reaction to fire of a thin material is tested on top of its application substrate, because the substrate determines how much heat accumulates and how much fuel is supplied to the flame. A 175 μm membrane does not have its own ‘classification’ independent of the material beneath it.