Fire stopping failures are found in over 90% of buildings surveyed post-Grenfell. This guide covers FIRAS certification, common defects, and how to ensure your building's compartmentation is intact.. The Hidden Vulnerability Fire stopping is the most critical — and most commonly deficient — element of building fire safety. Effective fire stopping seals every penetration through fire rated walls and floors, maintaining the compartmentation that is the foundation of fire safety design. Yet post Grenfell surveys have revealed a shocking truth: over 90% of buildings inspected have some level of fire stopping deficiency. What Is Fire Stopping? Fire stopping includes all materials and systems used to maintain the fire resistance of compartment walls and floors at points of penetration: Intumescent collars — expanding in fire to seal plastic pipe penetrations Fire rated sealants — mastic sealants tested to BS EN 1366 3/4 Fire pillows — for temporary or accessible penetrations Fire batts — mineral fibre boards for large openings Pipe wraps — intumescent wraps for combustible pipe penetrations Cable transit systems — modular systems for multiple cable penetrations Dampers — fire and smoke dampers in ductwork penetrations Fire rated putty — for small cable penetrations Common Failure Modes Installation Defects (found in 78% of surveyed buildings) 1. Wrong product for application — using sealant where a collar is required 2. Annular gap too large — exceeding tested configuration limits 3. Missing fire stopping — penetrations left unsealed entirely 4. Incorrect depth — sealant applied too thinly to achieve rated performance 5. Incompatible substrate — product applied to surface not covered by test evidence 6. Multiple services — exceeding tested density of penetrations per area Maintenance Defects (found in 64% of surveyed buildings) 1. New services installed without fire stopping 2. Damaged fire stopping not repaired after maintenance work 3. Fire stopping painted over — concealing defects 4. Access panels removed and not replaced 5. Building modifications breaching compartmentation without reinstatement FIRAS Certification FIRAS (Fire Industry Association Registration and Accreditation Scheme) is the UK's leading third party certification scheme for fire stopping contractors: What FIRAS Certification Means Trained operatives — all installers have completed accredited training Supervised installations — regular site audits by FIRAS assessors Photographic records — every installation photographed before concealment Test evidence — only products with valid fire test evidence used Completion certificates — formal certification of completed installations Warranty — backed by third party certification body Why FIRAS Matters Building Safety Act — competence requirements effectively mandate third party certification Insurance — many insurers now require FIRAS or equivalent certification Legal liability — uncertified fire stopping creates significant legal exposure Golden thread — FIRAS certificates form part of the building's digital record Inspection and Survey Type 3/4 Fire Risk Assessment Destructive inspection — opening up concealed spaces to check fire stopping Sampling strategy — statistically significant sample of penetrations Risk based prioritisation — focusing on high risk penetrations (vertical risers, flat entrance doors) Reporting — detailed defect schedule with photographic evidence Compartmentation Survey Process 1. Desktop review — original fire strategy, as built drawings, previous surveys 2. Non destructive survey — visual inspection of accessible fire stopping 3. Destructive inspection — opening up concealed penetrations at selected locations 4. Defect categorisation — critical, major, minor classification 5. Remediation specification — product specific repair specifications 6. Reinstatement — making good of opened up areas 7. Re inspection — verification of completed remediation works Cost of Fire Stopping Remediation Building Type Typical Defects Remediation Cost 20 flat residential block 50 100 £15,000 30,000 100 flat residential tower 200 500 £75,000 150,000 Commercial office (5,000m²) 100 250 £20,000 50,000 Hospital ward block 500 1,000+ £100,000 300,000 School building 50 150 £10,000 25,000 Maintenance Programme Annual visual inspection of all accessible fire stopping Permit to work system for any service penetrations through fire rated elements Sign off protocol — fire stopping reinstated and certified after every service intervention Photographic log — maintaining visual record of all fire stopping installations Training — ensuring maintenance teams understand fire stopping importance Magnus Opifex SEVEN LTD — UK's Leading Fire Safety & Fire Engineering Consultancy 🌐 magnus opifex.co.uk 📞 +44 7486 691724 ✉️ office@magnus opifex.co.uk Founders: Nicoleta Vasile, Baroness of Brattleby — CEO, Lawyer and Barrister, Legal & Administrative Director Alina — Technical Director & Expert Fire Engineer (BEng