From fire-rated walls and floors to intumescent coatings and firestopping — everything building owners need to know about passive fire protection systems and their critical role in compartmentation.. Understanding Passive Fire Protection Passive fire protection (PFP) forms the backbone of any building's fire safety strategy. Unlike active systems such as sprinklers and alarms that require activation, passive systems are built into the fabric of the structure itself — silently protecting occupants 24 hours a day, 365 days a year. The Building Safety Act 2022 and its associated regulations have placed renewed emphasis on passive fire protection, particularly in higher risk buildings. For building owners and managers, understanding these systems is no longer optional — it's a legal requirement. The Four Pillars of Passive Fire Protection 1. Structural Fire Protection Structural elements must maintain their load bearing capacity for a specified period during a fire. This is typically achieved through: Intumescent coatings — thin film paints that expand when heated, forming an insulating char layer Board systems — calcium silicate or gypsum based boards encasing structural steel Concrete encasement — traditional method still used in some applications Spray applied systems — cementitious or fibrous coatings applied directly to structural members 2. Compartmentation Compartmentation divides a building into fire resistant compartments, containing fire and smoke to their area of origin: Fire rated walls — typically 30, 60, 90, or 120 minute rated Fire rated floors — maintaining vertical separation between storeys Cavity barriers — preventing fire spread through concealed spaces Fire rated glazing — integrity only or integrity plus insulation rated 3. Fire Stopping Every service penetration through a fire rated element must be properly sealed: Intumescent wraps and collars for plastic pipes Fire rated sealants for cable penetrations Fire rated mortar for larger openings Proprietary fire stopping systems tested to BS EN 1366 series The golden rule: every penetration must be sealed to match the fire resistance of the element it passes through 4. Fire Resistant Doors Fire doors are arguably the most critical and most frequently failed element of passive fire protection: FD30 — 30 minute fire resistant door FD60 — 60 minute fire resistant door All fire doors must be third party certified Regular inspection and maintenance is essential Self closing devices must function correctly at all times Common Failures and How to Avoid Them Our experience across thousands of UK buildings reveals consistent patterns of failure: 1. Inadequate fire stopping — The single most common failure. Service penetrations left unsealed or sealed with non fire rated materials. 2. Breached compartment walls — Subsequent building works that breach fire rated walls without reinstatement. 3. Missing cavity barriers — Particularly in buildings with rainscreen cladding systems where cavity barriers in the external wall are absent or incorrectly installed. 4. Defective fire doors — Gaps exceeding 3mm, damaged intumescent strips, non functioning self closers, or doors wedged open. 5. Incorrect intumescent coatings — Wrong specification, insufficient thickness, or damage from subsequent trades. The Inspection and Maintenance Regime Under the Fire Safety (England) Regulations 2022, building owners must: Commission annual inspections of fire doors in communal areas Check flat entrance doors every time the property is accessed for other purposes Maintain records of all passive fire protection maintenance Ensure fire stopping is inspected as part of any refurbishment works Keep the 'golden thread' of building information up to date Cost Considerations Passive fire protection represents significant investment but offers unmatched reliability: System Typical Cost Range Lifespan Intumescent coating (steel) £15 40/m² 20 25 years Fire stopping (per penetration) £25 150 Building lifetime Fire door replacement £350 800 per leaf 15 20 years Cavity barrier installation £30 80/linear metre Building lifetime Compartment wall upgrade £80 200/m² Building lifetime For comprehensive passive fire protection surveys and remediation, contact Magnus Opifex.