Fire Safety in Façades: System Performance Over Individual Products
Continuing our focus on fire safety, this article explores why system performance matters more than individual product classifications. While a membrane might meet the required fire rating, compliance cannot be assumed without considering all components of the façade system, including tapes, grommets, and sealants. We will examine both new build and retrofit scenarios, highlighting the key standards, testing methods, and practical implications for architects and façade specialists.
Approved Document B, the cornerstone of UK fire safety regulations, is divided into two volumes: Volume 1 covers dwellings, while Volume 2 applies to non-residential buildings such as offices, shops, and factories. Both volumes focus on limiting fire spread within and between buildings, protecting escape routes, providing access for firefighters, and ensuring that building users receive clear fire safety information.
Recent amendments in 2025 have updated the framework. The outdated National Classes for fire testing have been replaced by the more rigorous European Standard BS EN 13501, sprinklers are now mandatory in all new care homes, and additional requirements for Regulation 38 mandate comprehensive delivery of fire safety information.
The Euroclass system, defined in BS EN 13501, classifies building products based on combustibility, smoke emission, and flaming droplet production. Membranes used in external walls above ground must achieve at least B-s3, d0. However, compliance does not stop at the membrane. Accessories such as tapes, sealants, and grommets must also meet equivalent fire ratings. A high-performance membrane paired with lower-performing accessories will compromise the system’s fire resistance, potentially putting occupants at risk. System continuity is critical, particularly in high-rise façades, where every second counts during a fire.
Even high-rated membranes cannot prevent fire spread if service penetrations are not properly sealed. The BS EN 1366-3 fire resistance test assesses the performance of pipes, cables, ducts, and other penetrations, ensuring that they maintain the integrity of fire-resisting structures under fire conditions. Collars, grommets, and sealants must all be fire-rated to avoid creating weak points in the system. By testing the entire assembly rather than individual components, architects and specifiers can ensure consistent, reliable fire safety across building projects.
Air and fire barriers are closely linked. Standards such as BS EN 12114, primarily designed to measure air permeability and improve energy efficiency, also contribute to fire safety by limiting pathways for smoke and flames. Discontinuous layers break both airtightness and fire safety, making it essential that membranes, tapes, and sealants are tested together as a complete system. Only then can professionals demonstrate compliance while achieving optimal safety and energy performance.
Retrofit projects present additional challenges. Many older buildings constructed before 2017 may feature Class E or untested membranes, leaving them vulnerable. While retrofit offers an opportunity to improve fire safety, energy efficiency, and occupant comfort, it must be approached carefully. The MHCLG, now DLUHC, has provided guidance on assessing combustible cladding systems, particularly aluminium composite materials (ACM) with polyethylene fillers, which can pose significant hazards on buildings over 18 metres tall. Compliance is demonstrated through BS 8414 large-scale cladding tests, system compatibility statements, and careful evaluation of existing assemblies.
Safe façade remediation requires a holistic view of the system rather than simple membrane replacement. The Declaration of Performance (DoP) documents product-level fire reaction, BS 8414 test reports demonstrate full system performance, and compatibility statements confirm that modified components still meet fire safety standards. Architects must ensure that all elements of the façade are compliant and that building occupants receive appropriate fire safety information.
For practical application, specifiers should always request EN 13501-1 classification reports for each product, BS 8414 system test evidence where relevant, and confirmation of accessory compatibility. By considering the entire system, architects can design façades that meet the latest regulations, improve fire safety, and provide reassurance to clients and occupants alike.
In conclusion, fire safety in façades cannot rely on individual products alone. Evidence-based system performance is essential, whether in new build or retrofit projects. By prioritising tested, compatible components and maintaining continuous barriers, architects and façade specialists can ensure that buildings are both compliant and safe, future-proofing them for years to come.
References
UK Government – Approved Document B: Fire Safety (2020 edition, with 2022 amendments)
Irish Government – Technical Guidance Document B – Fire Safety (2020)
Guidance Cladding remediation
NHBC – Standards 2021, Chapter 6.9 Curtain walling and cladding (NHBC, 2021):
Fire Resistance Test for Service Installations BS EN 1366 Part 3
Guidance Cladding remediation
EN 13501-1: Fire classification of construction products and building elements (CEN, 2018).
BS EN 1366-3: Fire resistance tests for service installations – Penetration seals (BSI, 2021).
BS 8414: Fire performance of external cladding systems (BSI, 2020).
