The Consolidated Compartment Fire Model (CCFM) computer code application CCFM. VENTS - part I:

Abstract

A project was carried out at The National Institute of Standards and Technology (NIST) to study the feasibility of developing a new-generation , multi-room, compartment fire model computer code, called the Consolidated Compartment Fire Model (CCFM) computer code. The idea was that such a code would consolidate past progress in zone-type compartment fire modeling, and allow readily for integration of future advances with the greatest possible flexibility. Desired features of the CCFM would include: comprehensive documentation, user-friendliness, significant modularity, nrimerical robustness, and versatility in the sense that the code would provide a capability of analyzing a particular compartment fire problem by using any one of a range of physical-phenomena-modeling sophistication, from the most basic to the most comprehensive. The project led to the development of a prototype multi-room CCFM product called CCFM. VENTS. CCFM. VENTS involves a model formulation and code structure that allows for the required future CCFM growth flexibility. It has a relatively sophisticated and very general room-to-room forced and unforced vent flow capability. Finally, the CCFM. VENTS code uses the simplest possible, point-source-plume, smokefilling fire physics in the rooms-offire-origin and a very simple heat transfer calculation there and in other spaces. This is Part I of a four-part report which documents the above effort. Introductory remarks discuss the generic features of the CCFM and the specific features of CCFM. VENTS. The main objective of this Part I document is to present a comprehensive description of the governing equations of CCFM. VENTS and their technical basis.

CFAST – Consolidated Model of Fire Growth and Smoke Transport (Version 6) Technical Reference Guide

“…These can range from very small containment vessels, on the order of 1 m 3 to large spaces on the order of 1000 m 3 . As discussed in the section on limitations and use (see section 2.1.9), the appropriate size fire depends on the size of the compartment being modeled.…”

“…Correcting for the orientation of the target and accounting for heat transfer through the gas layers, the heat flux to the target is 3 Radiative Heat Flux from a Wall Segment to a Target: Figure 3.14 illustrates terms used to compute heat flux from a wall segment to a target. The flux, q w,t , from a wall segment to a target can then be computed using…”

Verification and validation of CFAST :

“…These equations are derived from the conservation of mass and energy. Subsidiary equations are the ideal gas law and definitions of density and internal energy (for example, see [12]). These conservation laws are invoked for each zone or control volume.…”

“…The flux, q" w,t , from a wall segment to a target can then be computed using where q" w (out) is the flux leaving the wall segment, A w , A t are the areas of the wall segment and target respectively, F w-t is the fraction of radiant energy given off by the wall segment that is intercepted by the target (i.e. a configuration factor) and Equation (112) can be simplified using the symmetry relation A w F w-t = A t F t-w (see [55], eq (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) or [56]) to obtain where (see [55, eq (17-15) Radiation from the Gas Layer to the Target: Figure 19 illustrates the setup for calculating the heat flux from the gas layers to the target. The upper and lower gas layers in a room contribute to the heat flux striking the target if the layer absorptances is non-zero.…”

CFAST – Consolidated Model of Fire Growth and Smoke Transport (Version 7) Volume 1: Technical Reference Guide

“…This version was restructured from FAST [2] to incorporate the "lessons learned" from the zone model CCFM developed by Cooper and Forney [3]. Version 2 was released as a component of Hazard 1.2 in 1994 [4,5].…”