Overview - ISO/TR 16730-2:2013 (Fire zone model, CFAST)
ISO/TR 16730-2:2013 is a Technical Report in the ISO 16730 series on fire safety engineering. It shows how the general assessment, verification and validation procedures of ISO 16730‑1 are applied to a concrete calculation method: a two‑zone fire zone model (CFAST). The report documents the model equations, physical basis, implementation details, sensitivity and predictive capability, and provides worked examples and a user’s manual to illustrate verification and validation of the calculation method.
Key topics and technical requirements
- Scope and purpose: Demonstrates application of ISO 16730‑1 procedures to a specific calculation method for simulating fires in confined compartments with natural or forced ventilation.
- Model description (CFAST): A two‑zone (upper/lower) zone model that predicts time‑evolving temperature, layer height, pressure, smoke/gas concentrations and other environment variables in multi‑compartment structures.
- Governing principles: Equations are formulated as an initial‑value problem of ordinary differential equations (ODEs) based on conservation of mass, conservation of energy (first law of thermodynamics), the ideal gas law, and constitutive relations for density and internal energy.
- Numerical aspects: The ODE system is typically stiff (fast pressure adjustments vs slower thermal responses), requiring appropriate stiff solvers and computational strategies to ensure stable, efficient solutions.
- Assumptions and limitations:
- Zone‑model assumption of spatially averaged properties and sharp layer interface (stratification).
- Not intended for detailed local flow studies (e.g., detector siting) or highly complex geometries where CFD would be appropriate.
- Accuracy depends on user‑specified inputs (geometry, ventilation, thermal properties, heat release), and model validity is bounded by the scenarios documented in the report.
- Documentation and assessment: Annexes include a full method description (Annex A), verification/validation checklist and records (Annex B), a worked example (Annex C), and a user’s manual (Annex D).
Practical applications and users
- Applications:
- Fire and smoke spread prediction in buildings
- Timeline reconstruction in fire investigations
- Preliminary smoke‑control and ventilation design studies
- Estimating detector/suppression activation and life‑safety conditions
- Who should use it:
- Fire safety engineers and consultants
- Researchers validating fire models
- Regulatory bodies and authorities having jurisdiction (AHJs)
- Forensic investigators and designers performing system‑level analyses
- The report supports robust verification and validation practices that increase confidence when applying zone models in engineering decisions.
Related standards
- ISO 16730‑1 (general assessment, verification and validation procedures)
- Other parts of ISO 16730 series (CFD, structural, egress examples) - referenced in the TR.
Keywords: ISO/TR 16730-2:2013, fire safety engineering, CFAST, fire zone model, verification and validation, calculation methods, zone model, fire modelling.