A fire wall (Dutch: brandmuur) is a fire-resistant wall designed to separate two buildings or two sections of a building and prevent fire from spreading from one side to the other. It is one of the most fundamental elements of passive fire protection in construction.
Construction requirements
A fire wall must meet strict performance criteria that go beyond those of a standard fire compartment wall:
- Fire resistance — a fire wall is typically rated REI 120 or higher, meaning it maintains its load-bearing capacity (R), integrity (E), and insulation (I) for at least 120 minutes during a fire.
- Structural independence — the wall must remain standing even if the structure on one side collapses. This often requires the fire wall to be self-supporting and structurally separate from the roof and floor structures it divides.
- Continuity — the wall must extend from the foundation to above the roof line (or to the underside of a fire-rated roof) to prevent fire from bypassing it over the top.
- No unprotected openings — any door, window, or service penetration in a fire wall must be fitted with a fire-rated closure that matches the wall’s resistance rating.
Materials
Fire walls are commonly built from:
- Concrete blocks or in-situ concrete — providing high mass and excellent fire resistance.
- Calcium silicate blocks — lightweight yet fire resistant, popular for party walls in residential construction.
- Reinforced masonry — brick walls with steel reinforcement for structural stability.
Timber or steel-framed walls can achieve fire wall ratings when clad with multiple layers of fire-resistant board, but solid masonry or concrete solutions are more common and often simpler to certify.
Application in construction
Fire walls are required between adjoining row houses, semi-detached homes, and between units in commercial or industrial buildings. Building regulations specify when a fire wall is needed based on building use, size, and distance to the plot boundary. Ensuring the fire wall is correctly detailed at the roof junction, foundation, and any penetrations is critical for it to perform as intended.
Related terms
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