In fire engineering conversations, terms like “CFD analysis” and “CFD modelling” are often used interchangeably—but do they mean the same thing? Not quite. Understanding the subtle differences can help clarify communication with consultants, stakeholders, and regulatory bodies.
This article explains the distinction between CFD analysis and CFD modelling in a fire safety context, what they each involve, and when to use the correct terminology.
What Is CFD?
CFD stands for Computational Fluid Dynamics. It refers to the science and practice of simulating how gases and liquids move—in our case, how smoke and hot gases behave during a fire.
CFD Modelling: The Process
CFD modelling refers to the act of constructing a virtual 3D representation of a building or environment, setting parameters, and running a simulation using CFD software.
It includes:
- Creating the digital geometry (rooms, ducts, walls)
- Applying fire scenarios (heat release rate, fuel type)
- Defining boundary conditions (ventilation, openings)
- Selecting solver parameters and meshing
- The result is a model that mimics how fire and smoke behave in the space.
CFD Analysis: The Interpretation
CFD analysis is what comes after the model has run. It involves interpreting the simulation results to make informed decisions about fire safety strategy. It includes:
- Reviewing temperature and visibility graphs
- Identifying smoke layering and movement trends
- Evaluating whether safety thresholds are met
- Recommending design adjustments (e.g., additional vents, longer escape times)
| Term | Focus | Involves |
| CFD Modelling | Simulation Setup | Geometry, scenario input, boundary setup |
| CFD Analysis | Result Interpretation | Reviewing outcomes, decision-making |
Why It Matters
Understanding the distinction helps when:
- Commissioning Consultants: Know what you’re asking for
- Reporting to Authorities: Specify whether you need modelling to be done or results to be interpreted
- Budgeting and Planning: CFD modelling is resource-intensive; analysis is iterative
At FDS Consult UK, we offer both services:
- CFD Modelling to simulate real fire behaviour using FDS and PyroSim
- CFD Analysis to interpret existing models or validate third-party simulations
Use Case Example
You may already have a smoke ventilation design in place. Before reaching Gateway Two, partner with FDS Consult UK to:
- Build the CFD model of the building with proposed vents
- Run simulations with various fire load scenarios
- Analyse the results to check tenability limits and validate the fire strategy
CFD modelling and CFD analysis are two sides of the same coin—but they serve different purposes. One builds the simulation; the other makes sense of it. Both are critical in modern fire engineering and compliance.
Speak to our CFD specialists to find out whether your project needs a model built, analysed, or both.
