This presentation explores the fire safety challenges posed by Modern Methods of Construction (MMC), with a focus on lightweight floor systems and fire resistance performance.
- Introduction to MMC
- MMC includes techniques like volumetric construction, panelised systems, pre-cast concrete, digital design/BIM, and 3D printing.
- Key benefits: faster builds, improved quality, reduced waste, and increased safety through factory-based assembly.
- Fire Safety Challenges in MMC
- Void Spaces: Cavities between modules can allow hidden fire/smoke spread.
- Combustible Materials: Timber and foam insulation may behave unpredictably in fire.
- Joint Failures: Connections between modules are heat-sensitive and structurally vulnerable.
- Lightweight Floor Systems (as per ABCB)
- Prefabricated floor panels (e.g., CLT, timber, steel) are often enclosed and difficult to inspect.
- Performance depends on accurate installation, structural alignment, and the integrity of concealed fixings.
- Evidence for compliance may include test reports, CodeMark certificates, or engineering statements.
- Fire Resistance Testing – AS1530.4 Limitations
- Current DtS provisions only test floors for fire from below.
No standardized test exists for fire exposure from above, a real-world scenario where combustibles ignite on the upper surface. RISF – Resistance to Incipient Spread of Fire
- Testing showed incipient spread failure in as little as 66 minutes (against a target of 60 mins under <250°C).
- Direction of airflow (fluing) and structural voids critically affect performance.
- Fire From Above – Key Findings
- Fire exposure direction matters: Floors fail faster when attacked from above.
- Downward fire spread: Can lead to faster collapse due to flooring burnout.
- Overlay materials like gypsum boards improve performance.
- Research confirms: Conventional tests may overestimate floor fire performance.
- Superior flooring materials – combinations of fire resistant ceilings and high fire resistance flooring may be required for the
- Case Study & Testing Modifications
- Large-scale testing on Class 3/9c developments showed different behaviour in fire from above vs. below.
- Modified furnaces and real-world setups were used to simulate downward fire exposure.
- Service Penetrations – A New Focus
- Testing fire collars and plumbing penetrations in floor systems revealed vulnerabilities, especially in early stages (incipient spread).
- Risk of flue effect, rapid heat transfer, and insufficient closure by collars in minutes.
- Demonstrates the need for better design and testing of service penetrations in MMC floors.
