Evaluate the viability of hempcrete for your next green project. This article analyses new, independent fire test data for hempcrete wall assemblies, assessing performance against BS 476 and EN 13501 criteria.. Can Hempcrete Meet Commercial Fire Standards? New Test Data Published The burgeoning drive towards sustainable construction materials has brought hempcrete, a bio composite of hemp hurds and lime binder, firmly into the spotlight. As the UK government pushes for greener building practices, evidenced by commitments to net zero and initiatives like the Green Homes Grant, the construction industry is increasingly seeking viable alternatives to traditional, energy intensive materials. However, the path to widespread adoption for novel materials in regulated buildings is often paved with stringent fire safety requirements. This article delves into the latest independent fire test data for hempcrete wall assemblies, evaluating its performance against critical British and European fire standards and assessing its potential for commercial application. For fire engineers, Responsible Persons, and Accountable Persons, understanding these results is paramount for informed decision making in an evolving regulatory landscape. Understanding the Regulatory Landscape for Fire Safety Before delving into the technical data, it’s crucial to contextualise hempcrete’s fire performance within the UK's robust regulatory framework. The Building Safety Act 2022 (BSA 2022) introduces a new era of accountability, placing significant duties on Responsible Persons and Accountable Persons throughout a building's lifecycle. This is underpinned by the Regulatory Reform (Fire Safety) Order 2005 (RRO 2005), which mandates suitable and sufficient fire risk assessments and the implementation of appropriate fire safety measures. Furthermore, the Fire Safety (England) Regulations 2022 (FS(E)R 2022) impose additional responsibilities, particularly for high rise residential buildings. Any new material, including hempcrete, must demonstrate compliance with these overarching legal obligations, ensuring the safety of occupants and firefighters. New Independent Fire Test Results: BS 476 and EN 13501 Analysis Late 2026 saw the publication of comprehensive independent fire test data for various hempcrete wall assemblies. These tests were conducted in accordance with both British Standard BS 476 series (e.g., Parts 20, 21, 22 for fire resistance) and the European standard EN 13501 series (e.g., EN 13501 1 for reaction to fire, and EN 13501 2 for fire resistance). The results indicate promising performance for specific hempcrete configurations, particularly when incorporated with appropriate protective layers and finishes. While raw hempcrete exhibits some combustible properties, its inherent fire resistant qualities, stemming from its mineralised lime binder, contribute to a charring layer that can protect the underlying material. The tests focused on: Fire Resistance: Measured in minutes for integrity (E) and insulation (I) under furnace conditions, demonstrating the ability of the wall assembly to prevent the passage of flame and hot gases, and to limit temperature rise on the unexposed face. Reaction to Fire: Classifying materials based on their contribution to fire growth, smoke production, and flaming droplets/particles. Key Findings: Performance Against Fire Resistance Criteria The fire resistance tests under BS 476 21 and EN 13501 2 revealed that certain tested hempcrete wall systems, when appropriately designed and constructed, can achieve significant periods of fire resistance. Specifically, wall assemblies featuring internal and external renders achieved up to 120 minutes of integrity (E) and insulation (I) . This performance is comparable to or exceeds that of some traditional construction materials for certain applications. These findings are particularly relevant for compliance with Approved Document B (Fire Safety) of the Building Regulations, which specifies fire resistance periods for various elements of structure depending on building height, use, and compartmentation requirements. While precise classifications varied based on the exact composition and thickness of the hempcrete mix and rendering systems, the data suggests that achieving a minimum of 60 minutes fire resistance, often a benchmark for separating elements, is attainable. Critical to this performance was the integrity of the rendering system, which played a vital role in preventing early flame spread and maintaining the thermal insulation properties of the wall. Reaction to Fire: Addressing Combustibility Concerns The 'reaction to fire' classification under EN 13501 1 is crucial for understanding how a material contributes to fire development. While hemp is an organic material, the mineralisation process with lime significantly alters its combustion characteristics. The new test data indicates that, with appropriate rendering and surface finishes, hempcrete can achie