External wall fire safety assessment and compliance
Challenge
A five-storey residential building comprising 40 dwellings required a specialist external wall fire safety assessment to establish the as-built construction of its external wall systems, assess the potential for fire and smoke spread, and identify any significant fire safety risks.
The building owner required an evidence-based understanding of the fire risks associated with the external wall systems and proportionate risk-based remediation strategy, avoiding unnecessary wholesale replacement of the external wall construction where appropriate.
Project Description and Background
SOCOTEC was appointed to provide façade fire consultancy services for the building, which formed part of a wider regional portfolio. The scope covered a review of all available documentation, investigation of the existing external wall construction, assessment of fire and smoke spread risk, development of proportionate remediation measures, and post-remediation verification.
This type of assessment is increasingly relevant for building owners, developers and Owners’ Management Companies (OMCs) across Ireland, who hold responsibility for ensuring external wall systems meet current fire safety requirements – including the Building Regulations and the relevant provisions of Technical Guidance Document B.
Solution
SOCOTEC began with a desktop review of available documentation, including existing fire risk assessments, as-built drawings, O&M information, material data sheets, previous investigation records, and photographic evidence. This was followed by a non-intrusive site inspection to understand the building, identify representative external wall types, review relevant façade features, and establish suitable locations for intrusive investigation.
Intrusive openings were subsequently undertaken in accordance with an agreed investigation strategy to verify the construction of representative external wall types. SOCOTEC liaised directly with the client’s opening-up contractor to coordinate the inspection locations and ensure that sufficient information was obtained.
The investigation identified two principal wall types with significantly different risk profiles.
Wall Type 1 (WT1) consisted of brickwork over an uninsulated cavity with a timber-frame inner wall. Taking account of the wall configuration, limited cavity configuration, and relevant fire-spread mechanisms, WT1 was assessed as presenting a low risk for fire and smoke spread.
SOCOTEC began with a desktop review of available documentation, including existing fire risk assessments, as-built drawings, O&M information, material data sheets, previous investigation records, and photographic evidence. This was followed by a non-intrusive site inspection to understand the building, identify representative external wall types, review relevant façade features, and establish suitable locations for intrusive investigation.
Intrusive openings were subsequently undertaken in accordance with an agreed investigation strategy to verify the construction of representative external wall types. SOCOTEC liaised directly with the client’s opening-up contractor to coordinate the inspection locations and ensure that sufficient information was obtained.
The investigation identified two principal wall types with significantly different risk profiles.
Wall Type 1 (WT1) consisted of brickwork over an uninsulated cavity with a timber-frame inner wall. Taking account of the wall configuration, limited cavity configuration, and relevant fire-spread mechanisms, WT1 was assessed as presenting a low risk for fire and smoke spread.
Wall Type 2 (WT2) comprised timber cladding over a timber frame, with an OSB sheathing board and mineral wool insulation between the sheathing board and internal drylining. No cavity barriers were identified within the investigated areas. The wall was located adjacent to the building’s principal escape route and stair core. The combustible external wall components, cavity configuration, and location relative to the escape route were considered in assessing the potential for fire and smoke spread and its impact on occupant life safety. WT2 was assessed as presenting a medium level of risk.
For WT2, SOCOTEC recommended removing the existing timber cladding and replacing it with non-combustible materials achieving a medium European reaction-to-fire classification of A2-s1,d0 or better. The cavity was also recommended to be fully filled with non-combustible insulation, with new cavity barriers installed to reduce the potential for fire spread within the external wall system. The remediation strategy was developed to address and reduce the identified life-safety risk associated with the external wall system.
Following completion of the remedial works, SOCOTEC reviewed the installed construction and relevant completion documentation to provide post-remediation verification and supporting technical sign-off.
Conclusion
By identifying two distinct wall types with different risk profiles, SOCOTEC provided the client with a clear, evidence-based understanding of the external wall fire-risks across the building. The targeted remediation strategy focused intervention where it was needed most, avoiding unnecessary wholesale façade replacement and helping the client optimise capital expenditure.
SOCOTEC’s end-to-end involvement, from initial investigation through to post-remediation verification, gave the client confidence that the works had been completed to the required standard.
This project demonstrates how SOCOTEC’s combined façade engineering and fire safety expertise helps building owners, developers, and OMCs manage external wall risks proportionately, cost-effectively, and in line with current regulatory expectations.
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