FIREFLY™ Membrane NB is a high-performance, A2-rated non-breathable membrane engineered for use in commercial wall construction and façade applications. Manufactured from a woven glass substrate laminated with aluminium foil, it delivers outstanding fire resistance, weatherproofing, and durability while acting as a highly effective water and vapour barrier.
Designed for non-combustible wall build-ups, FIREFLY™ Membrane NB achieves EN 13501-1 Class A2-s1, d0 and BS 476 Parts 6 & 7 (Class 0), ensuring suitability for high-rise applications and fire-critical environments. Lightweight and robust, it’s easy to install and delivers long-term mechanical stability under demanding site conditions.
Key Features & Benefits:
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A2-s1, d0 Fire Rated – Fully compliant with EN 13501-1:2018 and BS 476 Parts 6 & 7
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Non-Breathable Barrier – Prevents moisture ingress; ideal for façades and rainscreen systems
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Durable & Strong – Woven glass substrate laminated with aluminium foil for mechanical resilience
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Lightweight & Easy to Install – Can be cut and fixed with standard tools; jointed using FIREFLY™ foil tape
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Weatherproof Protection – Acts as an impermeable layer for external wall applications
Technical Specifications:
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Dimensions: 1.25m wide x 50m long (62.5m² roll)
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Thickness: Approx. 0.2mm
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Weight: Approx. 14kg per roll
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Product Code: EKA161/1.25/50
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Fire Classification: A2-s1, d0 (EN 13501-1); Class 0 (BS 476 parts 6 & 7)
Installation Notes:
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Mechanical fixing is required—do not adhere using tape or adhesive directly to substrate
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Use stainless steel staples or self-drillers with washers depending on substrate type
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All joints and overlaps must be sealed using a fire-rated foil tape such as Bostik Idenden T303
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Horizontal overlaps: 150mm; vertical overlaps: 150mm; external corner overlaps: 300mm
Application Areas:
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Ventilated façades and rainscreen cladding
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Non-combustible external wall systems
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Projects requiring A2-rated fire-resistant membranes above 18m height
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Ideal for both new builds and refurbishments