Introduction

An approach for predicting various aspects of fire phenomena in compartments has been called zone modeling. It is based on a conceptual representation for the compartment fire process, and is an approximation to reality. Any radical departure by the fire system from the basic concept of the zone model can seriously affect the accuracy and validity of the approach. The zone model simply represents the system as two distinct compartment gas zones: an upper volume and a lower volume resulting from thermal stratification due to buoyancy. Conservation equations are applied to each zone and serve to embrace the various transport and combustion processes that apply. The fire is represented as a source of energy and mass, and manifests itself as a plume, which acts as a pump for the mass from the lower zone to the upper zone through a process called entrainment.

The zone modeling approach emerged in the mid-1970s when the effort to study the developing fire in a compartment intensified. Careful measurements and observations revealed characteristics of the compartment fire system. The upper and lower layers (zones) were deemed relatively uniform in temperature and composition. Distinct phenomena were discerned that could be studied in isolation, enabling better predictions of their roles in the compartment fire system.

Fowkes, ^[1] in his work with Emmons...