What are the two classes of fire models?

Fire models are fundamentally divided into two primary classes. Physical models are experimental and involve creating small-scale (reduced-scale) or full-scale physical mock-ups of a fire scenario to observe and measure fire phenomena. This approach relies on the principles of physical similarity. Mathematical models use systems of equations based on the fundamental laws of physics and chemistry (e.g., conservation of mass, momentum, and energy) to predict fire development and its effects. These are typically computer-based simulations, ranging from simple algebraic equations to complex computational fluid dynamics (CFD) models.

A. Open and closed: These terms describe thermodynamic systems or fire environments (e.g., an open-air fire vs. a compartment fire), not the classification of the models themselves.

B. Field and laboratory: This describes the location or scale of an experiment (a component of physical modeling), not the overarching classification that also includes mathematical models.

D. Behavioral and theoretical: These are non-standard and imprecise terms. The accepted, technically accurate classification in fire protection engineering is physical and mathematical.

1. SFPE Handbook of Fire Protection Engineering, 5th Edition. National Fire Protection Association, 2016.

Section 3, Chapter 39, "Introduction to Fire Modeling," Page 1285. The text explicitly states, "Fire models can be broadly classified as either physical models or mathematical models."

2. An Introduction to Fire Dynamics, 3rd Edition. by Drysdale, D. John Wiley & Sons, 2011.

Chapter 9, "Mathematical Modeling of Fire," Section 9.1, "Introduction," Page 405. The chapter distinguishes between experimental studies (physical modeling) and the development of mathematical models for predictive purposes.

3. University of Maryland, Department of Fire Protection Engineering Courseware (ENFP 429/625 - Fire Modeling).

Introductory lecture materials for fire modeling courses consistently introduce the fundamental dichotomy between physical scale modeling and mathematical/computational modeling as the two primary approaches to studying fire phenomena.