Overview
ISO/TS 16733-2:2021 - "Fire safety engineering - Selection of design fire scenarios and design fires - Part 2: Design fires" provides guidance for specifying design fires used in fire safety engineering (FSE) analyses of buildings and structures. It defines how to represent a fire as an engineering load to assess consequences (life safety, property, environment, heritage) and to challenge fire safety systems. The document complements ISO 16733-1 (scenario selection) and aligns with the performance-based process in ISO 23932-1.
Key topics
- Role of design fires in fire safety design and linkage to objectives such as occupant safety and property protection.
- Elements of a design fire: incipient, growth, flashover, fully developed, decay/extinction stages; effects of suppression, ventilation and enclosure.
- Constructing design fire curves: stepwise procedure covering input parameters, single/multiple fuels, power-law curves, flashover criteria, and maximum heat release rate for fuel-controlled and ventilation-controlled fires.
- Modifying curves for suppression systems, fire service intervention, and enclosure effects.
- Species production and yields (smoke and toxic products) relevant to life-safety and performance calculations.
- Design fires for structural fire engineering: localized fires, ceiling/impinging flames, parametric fires, travelling fires and implications for thermal loading of structures.
- External design fires, fire tests and probabilistic aspects (statistical representativeness, stochastic models, sampling).
- Documentation requirements to record assumptions, input data and results.
Practical applications
- Developing heat release rate (HRR) curves and time-temperature profiles for computational fire models (CFD, zone models) and engineering analysis.
- Assessing smoke production and toxic species for egress and tenability studies.
- Defining thermal loads for structural fire engineering and parametric fire design of elements.
- Evaluating effects of active systems (sprinklers, suppression) and vent changes on fire growth and decay.
- Supporting performance-based code compliance, risk assessments and peer-reviewed fire engineering reports.
Who should use this standard
- Fire safety engineers, structural engineers, and modelling specialists.
- Building designers, architects and consultants involved in performance-based design.
- Code authorities, fire investigators and researchers who require standardized methods to define design fires.
- Professionals conducting probabilistic fire risk assessments and documentation for regulatory review.
Related standards
- ISO 16733-1 (selection of design fire scenarios)
- ISO 23932-1 (performance-based fire safety engineering methodology)
- Other parts of the ISO 16733 series for complementary guidance
This technical specification is a practical resource for creating defensible, scenario-specific design fire representations used in modern fire safety engineering and performance-based design.
Open preview (PDF)Fire safety engineering — Selection of design fire scenarios and design fires — Part 2: Design fires
