NIST Special Publication 1086

December 2008 Revision

CFAST – Consolidated Model of Fire Growth

and Smoke Transport (Version 6)

Software Development and Model Evaluation Guide

Richard D. Peacock

Kevin McGrattan

Bryan Klein

Walter W. Jones

Paul A. Reneke

NIST Special Publication 1086

CFAST – Consolidated Model of Fire Growth

and Smoke Transport (Version 6)

Software Development and Model Evaluation Guide

Richard D. Peacock

Kevin McGrattan

Bryan Klein

Walter W. Jones

Paul A. Reneke

Fire Research Division

Building and Fire Research Laboratory

December 11, 2008

SVNRepository Revision : 80

UNITED STATES OF AMERICA

DEPARTMENT OF COMMERCE

U.S. Department of Commerce

Carlos M. Gutierrez, Secretary

National Institute of Standards and Technology

Patrick D. Gallagher, Deputy Director

Disclaimer

The U. S. Department of Commerce makes no warranty, expressed or implied, to users of CFAST

and associated computer programs, and accepts no responsibility for its use. Users of CFAST

assume sole responsibility under Federal law for determining the appropriateness of its use in any

particular application; for any conclusions drawn from the results of its use; and for any actions

taken or not taken as a result of analyses performed using these tools. CFAST is intended for use

only by those competent in the field of fire safety and is intended only to supplement the informed

judgment of a qualified user. The software package is a computer model which may or may not

have predictive value when applied to a specific set of factual circumstances. Lack of accurate

predictions by the model could lead to erroneous conclusions with regard to fire safety. All results

should be evaluated by an informed user.

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Intent and Use

The algorithms, procedures, and computer programs described in this report constitute a methodology for predicting some of the consequences resulting from a prescribed fire. They have been

compiled from the best knowledge and understanding currently available, but have important limitations that must be understood and considered by the user. The program is intended for use by

persons competent in the field of fire safety and with some familiarity with personal computers. It

is intended as an aid in the fire safety decision-making process.

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Preface

This supplement to the CFAST Technical Reference Guide provides details of the software development process for CFAST and accompanying experimental evaluation of the model. It is based

in part on the “Standard Guide for Evaluating the Predictive Capability of Deterministic Fire Models,” ASTM E 1355 [1]. ASTM E 1355 defines model evaluation as “the process of quantifying the

accuracy of chosen results from a model when applied for a specific use.” The model evaluation

process consists of two main components: verification and validation. Verification is a process

to check the correctness of the solution of the governing equations. Verification does not imply

that the governing equations are appropriate; only that the equations are being solved correctly.

Validation is a process to determine the appropriateness of the governing equations as a mathematical model of the physical phenomena of interest. Typically, validation involves comparing

model results with experimental measurement. Differences that cannot be explained in terms of

numerical errors in the model or uncertainty in the measurements are attributed to the assumptions

and simplifications of the physical model.

Evaluation is critical to establishing both the acceptable uses and limitations of a model.

Throughout its development, CFAST has undergone various forms of evaluation, both at the National Institute of Standards and Technology and beyond. This Supplement provides a survey of

validation work conducted to date to evaluate CFAST. Documentation of CFAST Verification is

contained in the CFAST Technical Reference Guide [2].

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Acknowledgments

Continuing support for CFAST is via internal funding at the National Institute of Standards and

Technology (NIST). In addition, support is provided by other agencies of the U.S. Federal Government, most notably the Nuclear Regulatory Commission (NRC) Office of Research and the U.S.

Department of Energy. The U.S. NRC Office of Research has funded key validation experiments,

the preparation of the CFAST manuals, and the continuing development of sub-models that are

of importance in the area of nuclear power plant safety. Special thanks to Mark Salley and Jason

Dreisbach for their efforts and support. Support to refine the software development and quality

assurance process for CFAST has been provided by the U.S. Department of Energy (DOE). The

assistance of Subir Sen and Debra Sparkman in understanding DOE software quality assurance

programs and the application of the process to CFAST is gratefully acknowledged. Thanks are

also due to Allan Coutts, Washington Safety Management Solutions for his insight into the application of fire models to nuclear safety applications and detailed review of the CFAST document

updates for DOE.

For the NIST/NRC tests, Alex Maranghides was in charge of the Large Fire Laboratory at NIST

where these tests were conducted, and helped to design the experiments. Thanks also to technicians

Laurean Delauter, Jay McElroy, and Jack Lee who constructed and conducted these validation experiments at NIST. Steve Nowlen at Sandia National Laboratories provided data, documentation

and further information for the NRC-sponsored experiments referred to in this document and the

”FM/SNL Test Series” (Factory Mutual and Sandia National Laboratories conducted these experiments). Finally, thanks to VTT, Finland, for their contribution of experimental data, referred to in

this document as the “VTT Large Hall Experiments.”

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Contents

Disclaimer i

Intent and Use iii

Preface v

Acknowledgments vii

1 Overview 1

1.1 Software Development and Quality Assurance . . . . . . . . . . . . . . . . . . . . 2

1.2 Model Validation Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.3 Input Data Required to Run the Model . . . . . . . . . . . . . . . . . . . . . . . . 3

1.4 Property Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.5 Model Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.6 Model Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.7 Uses and Limitations of the Model . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2 Software Quality Assurance 7

2.1 Relevant Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.2 Model Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.3 SQA Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.4 Standards, Practices, Conventions, and Metrics . . . . . . . . . . . . . . . . . . . 10

2.5 Software Reviews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.6 Model Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.7 Problem Reporting and Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.8 Tools, Techniques, and Methodologies . . . . . . . . . . . . . . . . . . . . . . . . 11

2.9 Media Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.10 Supplier Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.11 Records Collection, Maintenance, and Retention . . . . . . . . . . . . . . . . . . . 12

2.12 Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.13 Risk Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3 Software Structure and Robustness 13

3.1 Structure of the Numerical Routines . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.2 Comparison with Analytic Solutions . . . . . . . . . . . . . . . . . . . . . . . . . 15

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3.3 Code Checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.4 Numerical Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

4 Survey of Past Validation Work 17

4.1 Comparisons with Full-Scale Tests Conducted Specifically for the Chosen Evaluation 17

4.2 Comparisons with Previously Published Test Data . . . . . . . . . . . . . . . . . . 19

4.2.1 Fire Plumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.2.2 Multiple Compartments . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.2.3 Large Compartments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.2.4 Prediction of Flashover . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

4.3 Comparison with Documented Fire Experience . . . . . . . . . . . . . . . . . . . 23

4.4 Comparison with Experiments Which Cover Special Situations . . . . . . . . . . . 24

4.4.1 Nuclear Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

4.4.2 Small Scale Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.4.3 Unusual Geometry and Specific Algorithms . . . . . . . . . . . . . . . . . 25

5 Description of Experiments 29

5.1 NBS Single Room Tests with Furniture . . . . . . . . . . . . . . . . . . . . . . . 29

5.2 VTT Large Hall Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.3 NIST/NRC Test Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

5.4 FM/SNL Test Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.5 iBMB Compartment Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

5.6 NBS Multi-Compartment Test Series . . . . . . . . . . . . . . . . . . . . . . . . . 44

5.7 FM Four Room Including Corridor Test Series . . . . . . . . . . . . . . . . . . . . 49

5.8 NIST Seven-story Hotel Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

6 Hot Gas Layer Temperature and Depth 53

6.1 Model / Experiment Comparisons . . . . . . . . . . . . . . . . . . . . . . . . . . 55

6.2 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

7 Flame Height, Plume Temperature and Ceiling Jets 61

7.1 Flame Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

7.2 Plume Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

7.3 Ceiling Jets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

7.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

8 Gas Species and Smoke 65

8.1 Oxygen and CO2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

8.2 NIST/NRC Test Series, Smoke . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

8.3 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

9 Pressure 71

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10 Heat Flux and Surface Temperature 73

10.1 NIST/NRC Test Series, Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

10.2 NIST/NRC Test Series, Compartment Walls, Floor and Ceiling . . . . . . . . . . . 75

10.3 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

11 Summary and Conclusions 79

References 88

Appendix A: Calculation of Layer Height and the Average Upper and Lower Layer Temperatures 89

Appendix B: Model / Experiment Comparison Graphs 91

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List of Figures

2.1 CFAST SQA Organization Structure. . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.1 Subroutine structure for the CFAST model . . . . . . . . . . . . . . . . . . . . . . 14

4.1 Comparison of correlations, CFAST predictions, and experimental data for the

prediction of flashover in a compartment fire. . . . . . . . . . . . . . . . . . . . . 22

5.1 Plan and elevation view schematic of experimental room for NBS single room tests

with furniture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

5.2 Cut-Away View of Case 2 of the VTT Large Hall Tests. . . . . . . . . . . . . . . . 31

5.3 Plan, side and perspective schematic drawings of the experimental arrangement of

the VTT large hall fire tests, including the fuel pan . . . . . . . . . . . . . . . . . 32

5.4 Photo of a 2 MW heptane fire during the VTT large hall tests. Photo provided by

Simo Hostikka, VTT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

5.5 Prescribed Heat Release Rate as a Function of Time for VTT Large Hall Tests. . . 35

5.6 Photograph of a 1 MW heptane fire seen through the open doorway. Photo provided by Anthony Hamins, NIST. . . . . . . . . . . . . . . . . . . . . . . . . . . 36

5.7 Cross-section View of the NIST NRC Test Configuration. . . . . . . . . . . . . . . 36

5.8 Plan, side and perspective schematic drawings of the NIST NRC experimental

arrangement. The fuel pan and cables B, D, F, and G (dotted lines) are also shown. 37

5.9 Measured and prescribed heat release rate as a function of time during Test 3 of

the NIST NRC test series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.10 Detailed plan, side, and perspective schematic drawings of the FM/SNL experimental arrangement, including the supply and exhaust ducts, and the fuel pan. . . . 40

5.11 Prescribed (dotted line) and measured (solid line) heat release rate as a function of

time during Test 21 of the FM/SNL test series . . . . . . . . . . . . . . . . . . . . 41

5.12 Detailed plan, side, and perspective schematic drawings of the iBMB pool fire

experimental arrangement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

5.13 Estimated heat release rate for the iBMB fire experiments. . . . . . . . . . . . . . 44

5.14 Detailed plan, side, and perspective schematic drawings of the iBMB cable fire

experimental arrangement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

5.15 Photo of a 100 kW fire with the burner located against the rear wall of one of the

small compartments in the NBS Multi-Compartment test Series. . . . . . . . . . . 46

5.16 Overview of the NBS Test Configuration. . . . . . . . . . . . . . . . . . . . . . . 46

5.17 Plan, side and perspective schematic drawings of the NBS experimental arrangement, including the burner. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

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5.18 Prescribed and measured heat release rate as a function of time during Tests 100A

and 100Z of the NBS multi-room test series. . . . . . . . . . . . . . . . . . . . . . 48

5.19 Overview of the Factory Mutual Four Room test series. . . . . . . . . . . . . . . . 50

5.20 Overview of the NIST Seven-story hotel test series including smoke control. . . . . 51

6.1 Comparison of Measured and Predicted HGL Temperature and Height. . . . . . . . 56

7.1 Comparison of Measured and Predicted Ceiling Jet Temperature. . . . . . . . . . . 63

8.1 Comparison of Measured and Predicted Oxygen Concentration and Carbon Dioxide Concentration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

8.2 Comparison of Measured and Predicted Smoke Concentration. . . . . . . . . . . . 69

9.1 Comparison of Measured and Predicted Compartment Pressure. . . . . . . . . . . 72

10.1 Comparisons of Measured and Predicted Heat Flux to Targets and Target Temperature 74

10.2 Comparisons of Measured and Predicted Heat Flux to Compartment Surfaces and

Surface Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

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List of Tables

5.1 Thermophysical Properties for VTT Large Hall Tests . . . . . . . . . . . . . . . . 31

5.2 Test Matrix and Experimental Conditions for NIST NRC Tests . . . . . . . . . . . 38

6.1 Relative Difference for HGL Temperature and Depth for Two Measurement Locations in Two Single-Room Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

11.1 Summary of Model Comparisons . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

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Chapter 1

Overview

CFAST is a fire model capable of predicting the fire-induced environmental conditions as a function of time for single- or multi-compartment scenarios. Toward that end, the CFAST software

calculates the evolution of temperature, smoke, and fire gases throughout a building during a userprescribed fire. The model was developed, and is maintained, by the Fire Research Division of the

National Institute of Standards and Technology (NIST).

CFAST is a two-zone model, in that it subdivides each compartment into two zones, or control

volumes and the two volumes are assumed to be homogeneous within each zone. This two-zone

approach has evolved from observations of layering in actual fires and real-scale fire experiments.

Differential equations that approximate solution of the mass and energy balances of each zone,

equations for heat conduction into the walls, and the ideal gas law simulate the environmental

conditions generated by a fire.

This document describes the underlying structure of the CFAST model and the processes used

during the development and deployment of the model. It is intended to provide guidelines for

• the planning for modifications to the model,

• any required reviews for both software and associated documentation of the model,

• testing to be conducted prior to the release of an updated model,

• problem reporting and resolution,

• retention of records, source code, and released software over the life of the code.

Key to ensuring the quality of the software are ongoing validation testing of the model. To this

end, a compilation of past and present validation exercises for the CFAST model are presented.

Validation typically involves comparing model simulations with experimental measurements.

To say that CFAST is “validated” means that the model has been shown to be of a given level of

accuracy for a given range of parameters for a given type of fire scenario. Although the CFAST

developers periodically perform validation studies, it is ultimately the end user of the model who

decides if the model is adequate for the job at hand. Thus, this Guide does not and cannot be

considered comprehensive for every possible modeling scenario.

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1.1 Software Development and Quality Assurance

The development and maintenance of CFAST is guided by software quality assurance measures

for the planning of modifications to the model that provide required reviews for both software

and associated documentation of the model, define testing to be conducted prior to the release of

an updated model, describe problem reporting and resolution procedures, and ensure all records,

source code, and released software is kept available for the life of the code.

The internal structure of the model also has an impact on the ease of modification and correctness of the model. The method for incorporating new phenomena and ensuring the correctness of

the code was adopted as part of the consolidation of CCFM and FAST and has resulted in a more

transparent, transportable and verifiable numerical model. This transparency is crucial to a verifiable and robust numerical implementation of the predictive model as discussed in the sections on

code checking and numerical analysis. More recently, all of the software development and software tracking has been made available on the web to further enhance the software development

process.

1.2 Model Validation Scenarios

Key to ensuring the correctness and accuracy of the model are comparisons of the model with both

earlier versions of the model and with documented experimental data applicable to the intended

range of application of the model. When doing a validation study, the first question to ask is, “What

is the application?” There are countless fire scenarios to consider, but from the point of view of

validation, it is useful to divide them into two classes – those for which the fire is specified as an

input to the model and those for which the fire must be estimated by use of the model. The former

is often the case for a design application, the latter for a forensic reconstruction. Consider each in

turn.

Design applications typically involve an existing building or a building under design. A socalled “design fire” is prescribed either by a regulatory authority or by the engineers performing

the analysis. Because the fire’s heat release rate is specified, the role of the model is to predict the

transport of heat and combustion products throughout the room or rooms of interest. Ventilation

equipment is often included in the simulation, like fans, blowers, exhaust hoods, ductwork, smoke

management systems, etc. Sprinkler and heat and smoke detector activation are also of interest.

The effect of the sprinkler spray on the fire is usually less of interest since the fire is prescribed

rather than predicted. Detailed descriptions of the contents of the building are usually not necessary

because these items are not assumed to be burning, and even if they are, the burning rate will

be fixed, not predicted. Sometimes, it is necessary to predict the heat flux from the fire to a

nearby “target,” and even though the target may heat up to some prescribed ignition temperature,

the subsequent spread of the fire usually goes beyond the scope of the analysis because of the

uncertainty inherent in object to object fire spread.

Forensic reconstructions require the model to simulate an actual fire based on information that

is collected after the event, such as eye witness accounts, unburned materials, burn signatures, etc.

The purpose of the simulation is to connect a sequence of discrete observations with a continuous

description of the fire dynamics. Usually, reconstructions involve more gas/solid phase interaction

because virtually all objects in a given room are potentially ignitable, especially when flashover

2
occurs. Thus, there is much more emphasis on such phenomena as heat transfer to surfaces, pyrolysis, flame spread, and suppression. In general, forensic reconstructions are more challenging

simulations to perform because they require more detailed information about the room geometry

and contents, and there is much greater uncertainty in the total heat release rate as the fire spreads

from object to object.

CFAST has been applied for both design and reconstruction scenarios. For the former, specified design fires are typically used (e.g., reference [3]). For the latter, iterative simulation with

multiple model runs allow the user to develop fire growth inputs consistent with observed post fire

conditions.

1.3 Input Data Required to Run the Model

All of the data required to run the CFAST model reside in a primary data file, which the user

creates. Some instances may require databases of information on objects, thermophysical properties of boundaries, and sample prescribed fire descriptions. In general, the data files contain the

following information:

• compartment dimensions (height, width, length)

• construction materials of the compartment (e.g., concrete, gypsum)

• material properties (e.g., thermal conductivity, specific heat, density, thickness, heat of combustion)

• dimensions and positions of horizontal and vertical flow openings such as doors, windows,

and vents

• mechanical ventilation specifications

• fire properties (e.g., heat release rate, lower oxygen limit, and species production rates as a

function of time)

• sprinkler and detector specifications

• positions, sizes, and characteristics of targets

The CFAST Users Guide [4] provides a complete description of the required input parameters.

Some of these parameters have default values included in the model, which are intended to be

representative for a range of fire scenarios. Unless explicitly noted, default values were used for

parameters not specifically included in this validation study.

1.4 Property Data

Required inputs for CFAST must be provided with a number of material properties related to

compartment bounding surfaces, objects (called targets) placed in compartments for calculation of

3
object surface temperature and heat flux to the objects, or fire sources. For compartment surfaces

and targets, CFAST needs the density, thermal conductivity, specific heat, and emissivity.

For fire sources, CFAST needs to know the pyrolysis rate of fuel, the heat of combustion, stochiometric fuel-oxygen ratio, yields of important combustion products in a simplified combustion

reaction (carbon monoxide, carbon dioxide, soot, and others), and the fraction of energy released

in the form of thermal radiation.

These properties are commonly available in fire protection engineering and materials handbooks. Experimentally determined property data may also be available for certain scenarios. However, depending on the application, properties for specific materials may not be readily available.

A small file distributed with the CFAST software contains a database with thermal properties of

common materials. These data are given as examples, and users should verify the accuracy and

appropriateness of the data.

1.5 Model Outputs

Once the simulation is complete, CFAST produces an output file containing all of the solution

variables. Typical outputs include (but are not limited to) the following:

• environmental conditions in the room (such as hot gas layer temperature; oxygen and smoke

concentration; and ceiling, wall, and floor temperatures)

• heat transfer-related outputs to walls and targets (such as incident convective, radiated, and

total heat fluxes)

• fire intensity and flame height

• flow velocities through vents and openings

• detector and sprinkler activation times

Thus, for a given fire scenario, there are a number of different quantities that the model predicts

A typical fire experiment can produce hundreds of time histories of point measurements, each

of which can be reproduced by the model to some level of accuracy. It is a challenge to sort

out all the plots and graphs of all the different quantities and come to some general conclusion.

For this reason, this Guide is organized by output quantity, not by individual experiment or fire

scenario. In this way, it is possible to assess, over a range of different experiments and scenarios,

the performance of the model in predicting a given quantity. Overall trends and biases become

much more clear when the data is organized this way.

1.6 Model Accuracy

The degree of accuracy for each output variable required by the user is highly dependent on the

technical issues associated with the analysis. The user must ask: How accurate does the analysis

have to be to answer the technical question posed? Thus, a generalized definition of the accuracy

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required for each quantity with no regard as to the specifics of a particular analysis is not practical

and would be limited in its usefulness.

Returning to the earlier definitions of “design” and “reconstruction,” fire scenarios, design

applications typically are more accurate because the heat release rate is prescribed rather than

predicted, and the initial and boundary conditions are far better characterized. Mathematically, a

design calculation is an example of a “well-posed” problem in which the solution of the governing

equations is advanced in time starting from a known set of initial conditions and constrained by a

known set of boundary conditions. The accuracy of the results is a function of the fidelity of the

numerical solution, which is largely dependent on the quality of the model inputs. This CFAST

validation guide includes efforts to date involving well-characterized geometries and prescribed

fires. These studies show that CFAST predictions vary from being within experimental uncertainty

to being about 30 % different than measurements of temperature, heat flux, gas concentration, etc

(see, for example, reference [5]).

A reconstruction is an example of an “ill-posed” problem because the outcome is known

whereas the initial and boundary conditions are not. There is no single, unique solution to the

problem. Rather, it is possible to simulate numerous fires that produce the given outcome. There

is no right or wrong answer, but rather a small set of plausible fire scenarios that are consistent

with the collected evidence and physical laws incorporated into the model. These simulations are

then used to demonstrate why the fire behaved as it did based on the current understanding of fire

physics incorporated in the model. Most often, the result of the analysis is only qualitative. If there

is any quantification at all, it could be in the time to reach critical events, like a roof collapse or

room flashover.

1.7 Uses and Limitations of the Model

CFAST has been developed for use in solving practical fire problems in fire protection engineering.

It is intended for use in system modeling of building and building components. A priori prediction

of flame spread or fire growth on objects is not modeled. Rather, the consequences of a specified

fire is estimated. It is not intended for detailed study of flow within a compartment, such as is

needed for smoke detector siting. It includes the activation of sprinklers and fire suppression by

water droplets.

The most extensive use of the model is in fire and smoke spread in complex buildings. The

efficiency and computational speed are inherent in the few computation cells needed for a zone

model implementation. The use is for design and reconstruction of time-lines for fire and smoke

spread in residential, commercial, and industrial fire applications. Some applications of the model

have been for design of smoke control systems.

• Compartments: CFAST is generally limited to situations where the compartment volumes

are strongly stratified. However, in order to facilitate the use of the model for preliminary estimates when a more sophisticated calculation is ultimately needed, there are algorithms for

corridor flow, smoke detector activation, and detailed heat conduction through solid boundaries. This model does provide for non-rectangular compartments, although the application

is intended to be limited to relatively simple spaces. There is no intent to include complex

geometries where a complex flow field is a driving force. For these applications, computational fluid dynamics (CFD) models are appropriate.

5
• Gas Layers: There are also limitations inherent in the assumption of stratification of the gas

layers. The zone model concept, by definition, implies a sharp boundary between the upper

and lower layers, whereas in reality, the transition is typically over about 10 % of the height

of the compartment and can be larger in weakly stratified flow. For example, a burning

cigarette in a normal room is not within the purview of a zone model. While it is possible

to make predictions within 5 % of the actual temperatures of the gas layers, this is not the

optimum use of the model. It is more properly used to make estimates of fire spread (not

flame spread), smoke detection and contamination, and life safety calculations.

• Heat Release Rate: CFAST does not predict fire growth on burning objects. Heat release

rate is specified by the user for one or more fire objects. The model does include the ability

to limit the specified burning based on available oxygen. There are also limitations inherent

in the assumptions used in application of the empirical models. As a general guideline,

the heat release should not exceed about 1 MW/m3. This is a limitation on the numerical

routines attributable to the coupling between gas flow and heat transfer through boundaries

(conduction, convection, and radiation). The inherent two-layer assumption is likely to break

down well before this limit is reached.

• Radiation: Because the model includes a sophisticated radiation model and ventilation algorithms, it has further use for studying building contamination through the ventilation system,

as well as the stack effect and the effect of wind on air circulation in buildings. Radiation

from fires is modeled with a simple point source approximation. This limits the accuracy of

the model near fire sources. Calculation of radiative exchange between compartments is not

modeled.

• Ventilation and Leakage: In a single compartment, the ratio of the area of vents connecting

one compartment to another to the volume of the compartment should not exceed roughly

1/2 m. This is a limitation on the plug flow assumption for vents. An important limitation

arises from the uncertainty in the scenario specification. For example, leakage in buildings

is significant, and this affects flow calculations especially when wind is present and for tall

buildings. These effects can overwhelm limitations on accuracy of the implementation of

the model. The overall accuracy of the model is closely tied to the specificity, care, and

completeness with which the data are provided.

• Thermal Properties: The accuracy of the model predictions is limited by how well the user

can specify the thermophysical properties. For example, the fraction of fuel which ends up

as soot has an important effect on the radiation absorption of the gas layer and, therefore, the

relative convective versus radiative heating of the layers and walls, which in turn affects the

buoyancy and flow. There is a higher level of uncertainty of the predictions if the properties

of real materials and real fuels are unknown or difficult to obtain, or the physical processes

of combustion, radiation, and heat transfer are more complicated than their mathematical

representations in CFAST.

In addition, there are specific limitations and assumptions made in the development of the

algorithms. These are detailed in the discussion of each of these sub-models in the NIST Technical

Reference Guide [2].

6
Chapter 2

Software Quality Assurance

This chapter describes the processes used during the development and deployment of the Consolidated Fire and Smoke Transport model (CFAST). This software quality assurance (SQA) plan is

intended to guide the planning for modifications to the model, provide required reviews for both

software and associated documentation of the model, define testing to be conducted prior to the

release of an updated model, describe problem reporting and resolution procedures, and ensure

all records, source code, and released software is kept available for the life of the code. While

this memorandum and many of our practices follow the Institute of Electrical and Electronics Engineers (IEEE) standard for software quality assurance, IEEE 730-2002 [6], other standards have

been followed as well. Most notably, ASTM 1355-05, Standard Guide for Evaluating the Predictive

Capability of Deterministic Fire Models [1] has been used extensively to guide the documentation,

verification, and validation of the model.

CFAST is intended for use only by those competent in the field of fire safety and is intended

only to supplement the informed judgment of the qualified user. The software package is a computer model which has limitations based on the way it is used, and the data used for calculations.

All results should be evaluated by a qualified user.

The SQA process and requirements outlined in this chapter apply specifically to the CFAST and

is focused on ensuring the quality of the numerical predictions of the model. The user interface that

may be used to develop input for the model is included in this process to insure that changes to the

model are reflected in the user interface and in the data files created by the user interface for use by

the model. Of course, users must ensure that the input files developed for the simulations accurately

reflect the desired model inputs, whether developed using the supplied user interface, another thirdparty interface, or manually input with a spreadsheet or text editor program. Documentation of

these inputs is included as part of the model documentation outlined below.

2.1 Relevant Publications

To accompany the model and simplify its use, NIST has developed a Technical Reference Guide

[2] and a User’s Guide [4] and this Software and Validation Guide. The Technical Reference Guide

describes the underlying physical principles and summarizes sensitivity analysis, model validation,

and model limitations consistent with ASTM E 1355 [1]. The Users Guide describes how to use

the model.

7
Fire Modeling

Staff

Fire Modeling

Group Leader

Engineered Fire Safety

Group Leader

Engineered Fire Safety

Staff

CFAST

Technical Lead

CFAST

Project Team

- Approves all research activities

- Review and approval of all

reports and software

- Review and approval of group

reports and software

- Approves all changes to activities

- Assists in development and 

oversees SQA activities

- Manage development, testing,

maintenance, and release

of CFAST

- Responsible for compliance with

SQA plans

- Develop software specifications

- Responsible for product quality

- Implements software quality activities

- Design and implementation of product

and documentation

Washington Editorial

Review Board

- Provides independent policy,

technical, and editorial review

of all reports and software

- Provide independent technical

review of CFAST reports and

software

- Assists in implementation of SQA

activities

- Assists in implementation of SQA activities

- Responsible for implementation and

maintenance of software repository

error reporting, and user feedback

Fire Research Division

Chief

Figure 2.1: CFAST SQA Organization Structure.

The U.S. Nuclear Regulatory Commission has published a verification and validation study of

five selected fire models commonly used in support of risk-informed and performance-based fire

protection at nuclear power plants [5]. In addition to an extensive study of the CFAST model, the

report compares the output of several other models ranging from simple hand calculations to more

complex CFD codes such as the Fire Dynamics Simulator (FDS) developed by NIST.

While this document and many of our practices make extensive use of ASTM 1355, Standard Guide for Evaluating the Predictive Capability of Deterministic Fire Models [1] to guide the

documentation, verification, and validation of the model, other standards have been followed as

well. Most notably, our software quality assurance processes were guided by the IEEE standard

for software quality assurance, IEEE 730-2002 [6].

In addition, numerous related documents available at http://cfast.nist.gov provide a wealth of

information concerning including earlier versions of the model and its user interface. Software

quality assurance (SQA) plan is intended to guide the planning for modifications to the model,

provide required reviews for both software and associated documentation of the model, define

testing to be conducted prior to the release of an updated model, describe problem reporting and

resolution procedures, and ensure all records, source code, and ensure released software is kept

available for the life of the code.

2.2 Model Management

CFAST is developed and maintained by the Building and Fire Research Laboratory (BFRL) at the

National Institute of Standards and Technology (NIST). Like all projects at BFRL, a designated

project leader is responsible for directing and prioritizing model development, error correction,

and preparation of documentation for the model development. The organization chart in Figure

2.1 provides a graphical representation of the software quality organization structure for CFAST

Review and approval of software and documentation is part of the standard review process for

any report or other product developed by NIST. A minimum of five reviews are required prior to

8
release of reports or software, including two independent technical peer reviews, two technical

and management reviews at the technical workgroup and division level, and a policy review at the

NIST-wide level. This review is documented and recorded on the NIST standard form NIST 114

along with official approval notification provided to the primary author of the product.

CFAST is distributed exclusively through a NIST website dedicated to the CFAST model

(http://cfast.nist.gov). Content of the website is the responsibility of the CFAST project leader

and the BFRL webmaster. Additions and changes to the website are made only with the approval

of the CFAST project leader after any required NIST reviews.

2.3 SQA Documentation

The released version of CFAST is documented by three primary publications, the Technical Reference Guide[2], the Users Guide [4], and this Software and Model Evaluation Guide. The documents apply to the newest version of the model available on the NIST website. The Technical

Reference Guide describes the underlying physical principles, provides a review of model verification and validation efforts by NIST and others, and describes the limitations of the model. The

User’s Guide describes how to use the model, includes a detailed description of the model inputs

and outputs, and provides a process to ensure the correct installation of the model. There are also

documents archived on the website that are applicable to older versions of both the model and user

interface.

During development of new or corrected features for the model, the following documents are

developed:

• Software Requirements and Design Specifications: This is an internal memorandum that

documents the intended function of a new or enhanced feature, describes its implementation

in sufficient detail to allow an independent review of the feature, and identifies any new

or existing testing and validation required prior to acceptance of the feature in a release

version of the model. This document forms the basis for necessary changes to the technical

reference guide and users guide for the model once the new feature is ready for general

release. As defined in IEEE 730-2002 [6], this document includes the software requirements

specification, software design description, and software verification and validation plan. The

level of detail in this document depends on the complexity of the change to the model.

• Software Validation and Testing Results: This is an internal memorandum that demonstrates

the use of the new feature through appropriate test cases and describes validation and verification tests performed to ensure the new feature is implemented properly without unexpected

changes in other features. This document forms the basis for the model verification and validation documentation included as part of this Software and Experimental Validation guide.

As defined in IEEE 730-2002 [6], this document includes the software verification and validation report. The level of detail in this document depends on the complexity of the change

to the model.

Both of these documents are reviewed internally to NIST by group staff not directly involved

with model development. In addition, the NIST review process documents the review and approval

of released versions of the model as described above.

9
Source code for released versions of the model is maintained with version control software that

allows tracking of specific changes to the model from version to version. Each version of the model

released includes a unique version number that identifies the major and minor version numbers of

the release as well as the date of release. Differences with prior versions are documented and

provided as part of the release and on the CFAST website so that users can ascertain what effect

these changes will have on prior calculations.

2.4 Standards, Practices, Conventions, and Metrics

Prior to final implementation of a new feature or change, a review of the proposed modification

is conducted by a developer who is not involved in the modification. This review includes review

and concurrence of the software requirements and design specification as well as more detailed

review of code changes as the complexity of the modification requires. Review and acceptance of

the software requirements and design specification by interested project sponsors or users may be

included as appropriate. Name and date of approval and/or review is noted electronically in the

document.

Review of the testing and validation report is also conducted by a developer who is not involved

in the modification prior to proposed model release. Any significant changes in model output

(typically a change greater than 1 % of a given output) should be explained based on changes to the

code as a result of a new feature. Name and date of approval and/or review is noted electronically

in the document.

2.5 Software Reviews

Software reviews are outlined as part of the standard practices described above. The standard

NIST review process includes review of software and documentation prior to any report or product

release by NIST.

2.6 Model Testing

Individual testing of model algorithms are made by the developers during any revision of the

model. Often, this testing forms the basis for any new standard test cases included with future

model releases. System release testing of the model prior to release includes the following:

• Examination of results of test cases specific to any model modifications made as appropriate.

Comparison with analytic solutions to simplified problems is desirable when available.

• Examination of results of standard test cases included with the release version of the model.

Any changes in the output from prior versions is explained (and documented in the software

testing and validation results report) by modifications made to the model.

• For major new releases of the model, a complete suite of test cases should be compared to

those from previous versions of the model. At a minimum this includes the set of valida10
tion exercises described in NUREG 1824 [7], but may include additional example cases or

validation exercises as appropriate.

2.7 Problem Reporting and Resolution

NIST maintains an e-mail address specifically for inquiries and problem reporting for the CFAST

model (cfast@nist.gov). These e-mails are directed to the CFAST project leader for response and

resolution as appropriate. Inquiries and responses are catalogued and retained by the project leader.

NIST has developed an automated reporting and resolution tracking website for use with the

CFAST model to facilitate tracking and cataloging of inquires, problems, and model enhancements

/ revisions. This is included as part of the CFAST website at http://cfast.nist.gov

2.8 Tools, Techniques, and Methodologies

NIST will use an automated comparison tool (under development) to compare CFAST predictions

between different versions of the model and with experimental data to simplify testing and validation for the CFAST model.

2.9 Media Control

Release versions of the CFAST model are available exclusively on the CFAST specific website

maintained by the Building and Fire Research Laboratory (BFRL) at NIST. This website is included in NISTs automated backup and recovery system for computer systems organization wide.

Development versions of the model are maintained by the CFAST project leader. All software and documents are included in NISTs automated backup and recovery system for computer

systems organization wide.

Both of these computer systems are available only to specified personnel, including the CFAST

project leader and BFRL webmaster.

2.10 Supplier Control

CFAST is entirely a product of BFRL / NIST and as such does not include any commercial software

libraries. The differential equation solver used by CFAST, DASSL, is a publicly available software

package. Full source code for the solver as used by CFAST is maintained under version control

with the rest of the model code.

BFRL currently uses Microsoft Visual Studio 2005 and Intel Visual Fortran 10.1 for development1

. Prior to any change to a different development system, a full test suite of test cases must be

compared to verify consistent operation of the model and model results.

1Certain commercial entities, equipment, or materials may be identified in this document in order to describe

an experimental procedure or concept adequately. Such identification is not intended to imply recommendation or

endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the entities,

materials, or equipment are necessarily the best available for the purpose.

11
2.11 Records Collection, Maintenance, and Retention

All software, documentation, and SQA documents are retained by the CFAST project leader, typically in electronic form. Software and documentation is also maintained and archived on the NIST

CFAST website as part of the version control software for the model.

BFRL management approval is required prior to destruction of old or out-of-date records.

Records are typically maintained for a minimum of 25 years.

2.12 Training

No specific training is identified for use of this SQAP. Details of training requirements for use of

the model included in the CFAST users guide is applicable to developers of the model as well.

2.13 Risk Management

The primary risk management tool for software developed and released by NIST is the official

NIST review process for software, documents, and other products of NIST. Official approval is

required prior to release of the model for general use.

12
Chapter 3

Software Structure and Robustness

The mathematical and numerical robustness of a deterministic computer model depends upon three

issues: the code must be transparent so that it can be understood and modified by visual inspection;

it must be possible to check and verify with automated tools; and there must be a method for

checking the correctness of the solution, at least for asymptotic (steady state) solutions (numerical

stability and agreement with known solutions). In order to understand the meaning of accuracy and

robustness, it is necessary to understand the means by which the numerical routines are structured.

In this chapter, details of the implementation of the model are presented, including the tests used

to assess the numerical aspects of the model. These include:

• the structure of the model, including the major routines implementing the various physical

phenomena included in the model,

• the organization of data initialization and data input used by the model,

• the structure of data used to formulate the differential equations solved by the model,

• a summary of the main control routines in the model that are used to control all input and

output, initialize the model and solve the appropriate differential equation set for the problem

to be solved,

• the means by which the computer code is checked for consistency and correctness,

• analysis of the numerical implementation for stability and error propagation, and

• comparison of the results of the system model with simple analytical or numerical solutions.

3.1 Structure of the Numerical Routines

A methodology which is critical to verification of the model is the schema used to incorporate physical phenomena. This is the subroutine structure discussed below. The method for incorporating

new phenomena and ensuring the correctness of the code was adopted as part of the consolidation

of CCFM and FAST. This consolidation occurred in 1990 and has resulted in a more transparent,

transportable and verifiable numerical model. This transparency is crucial to a verifiable and robust

13
Main Routine

Solve Auxiliary Equations

Solve Differential Equations

Calculate Right-hand Side of

Differential Equations and

Residuals

Input Routines

Output Routines

CFAST

SOLVE

DASSL

RESID

MFLOW HFLOW VFLOW FIRES DJET CJET CVHEAT CNHEAT RDHEAT HCL

Mechanical

Ventilation

Horizontal

Flow

Vertical

Flow

Fire

Chemistry

Door Jet

Fires

Ceiling

Jets

Conduction Convection Radiation HCl

Deposition

Output

Outputsmv

Outputspreadsheet

Readinputle

Keywordcases

Inputmainre

Inputobject

Inputtpp

Readcsvformat

Physical Interface Routines

Figure 3.1: Subroutine structure for the CFAST model showing major routines and calling structure.

numerical implementation of the predictive model as discussed in the sections on code checking

and numerical analysis.

The model can be split into distinct parts. There are routines for reading data, calculating results

and reporting the results to a file or printer. The major routines for performing these functions are

identified in figure 3.1. These physical interface routines link the CFAST model to the actual

routines which calculate quantities such as mass or energy flow at one particular point in time for

a given environment.

The routines SOLVE, RESID and DASSL are the key to understanding how the physical equations are solved. SOLVE is the control program that oversees the general solution of the problem.

It invokes the differential equation solver DASSL [8] which in turn calls RESID to solve the transport equations. Given a solution at time t, what is the solution at time t plus a small increment of

time, δt? The differential equations are of the form

dy

dx

= f(y,t) (3.1)

y(t0) = y0

where y is a vector representing pressure, layer height, mass and such, and f is a vector function

that represents changes in these values with respect to time. The term y0 is an initial condition

at the initial time t0. The time increment is determined dynamically by the program to ensure

convergence of the solution at t + ∆t. The subroutine RESID computes the right hand side of

eq 3.1 and returns a set of residuals of that calculation to be compared to the values expected

by DASSL. DASSL then checks for convergence. Once DASSL reaches an error limit (defined

as convergence of the equations) for the solution at t + ∆t, SOLVE then advances the solution

14
of species concentration, wall temperature profiles, and mechanical ventilation for the same time

interval. Note that there are several distinct time scales that are involved in the solution of this type

of problem. The fastest will be chemical kinetics. In CFAST, chemical reactions are assume to

be instantaneous so we ignore the impact of chemical kinetics. The next larger time scale is that

associated with the flow field. These are the equations which are cast into the form of ordinary

differential equations. Then there is the time scale for mechanical ventilation, and finally, heat

conduction through objects.

Chemical kinetic times are typically on the order of milliseconds. The transport time scale

are on the order of 0.1 s. The mechanical ventilation and conduction time scales are typically

several seconds, or even longer. The time step is dynamically adjusted to a value appropriate for

the solution of the currently defined equation set. In addition to allowing a more correct solution

to the pressure equation, very large time steps are possible if the problem being solved approaches

steady-state.

3.2 Comparison with Analytic Solutions

Certain CFAST sub-models address phenomena that have analytical solutions, for example, one

dimensional heat conduction through a solid or pressure increase in a sealed or slightly leaky

compartment as a result of a fire or fan. The developers of CFAST use analytical solutions to test

sub-models to verify the correctness of the coding of the model as part of the development. Such

verification efforts are relatively simple and the results may not always be published or included in

the documentation. Two additional types of verification are possible. The first type, discussed in

Section 3, Theoretical Basis, involves validating individual algorithms against experimental work.

The second involves simple experiments, especially for conduction and radiation, for which the

results are asymptotic (e.g., a simple single-compartment test case with no fire, all temperatures

should equilibrate asymptotically to a single value). Such comparisons are common and not usually

published.

3.3 Code Checking

Two standard programs have been used to check the CFAST model structure and language. Specifically, FLINT and LINT have been applied to the entire model to verify the correctness of the

interface, undefined or incorrectly defined (or used) variables and constants, and completeness of

loops and threads.

The CFAST code has also been checked by compiling and running the model on a variety

of computer platforms. Because FORTRAN and C are implemented differently for various computers, this represents both a numerical check as well as a syntactic check. CFAST has been

compiled for Sun (Solaris), SGI (Irix), Microsoft Windows-based PCs (Lahey, Digital, and Intel

FORTRAN), and Concurrent computer platforms. Within the precision afforded by the various

hardware implementations, the model outputs are identical on the different platforms. 1

1Typically an error limit of one part in 106 which is the limit set for the differential equation solver in the solution

of the CFAST equations

15
The CFAST Technical Reference Guide [2] contains a detailed description of the CFAST subroutine structure and interactions between the subroutines.

3.4 Numerical Tests

CFAST is designed to use 64-bit precision for real number calculations to minimize the effects of

numerical error.

The differential and algebraic equation solver (called DASSL) has been tested for a variety of

differential equations and is widely used and accepted [8]. The radiation and conduction routines

have also been tested against known solutions for asymptotic results [9].

Coupling between the physical algorithms of the model and the differential equation solver

also works to ensure numerical accuracy by dynamically adjusting the time step used by the model

to advance the solutions of the equation set. Solution tolerances are set to require solution of

the model equations within one part in 106. This ensures that the error attributable to numerical

solution is far less than that associated with the model assumptions.

16
Chapter 4

Survey of Past Validation Work

CFAST has been subjected to extensive validation studies by NIST and others. There are two ways

of comparing predictive capability with actual events. The first is simply graphing the time series

curves of model results with measured values of variables such as temperature. Another approach

is to consider the time to critical conditions such as flashover. Making such direct comparisons between theory and experiment provides a sense of whether predictions are reasonable. This chapter

provides a review of CFAST validation efforts by NIST and others to better understand the quality

of the predictions by the model.

Some of the work has been performed at NIST, some by its grantees and some by engineering

firms using the model. Because each organization has its own reasons for validating the model, the

referenced papers and reports do not follow any particular guidelines. Some of the works only provide a qualitative assessment of the model, concluding that the model agreement with a particular

experiment is “good” or “reasonable.” Sometimes, the conclusion is that the model works well in

certain cases, not as well in others. These studies are included in the survey because the references

are useful to other model users who may have a similar application and are interested in qualitative

assessment. It is important to note that some of the papers point out flaws in early releases of

CFAST that have been corrected or improved in more recent releases. Some of the issues raised,

however, are still subjects of active research. Continued updates for CFAST are greatly influenced

by the feedback provided by users, often through publication of validation efforts.

4.1 Comparisons with Full-Scale Tests Conducted Specifically

for the Chosen Evaluation

Several studies have been conducted specifically to validate the use of CFAST in building performance design. Dembsey [10] used CFAST version 3.1 to predict the ceiling jet temperatures,

surface heat fluxes and heat transfer coefficients for twenty compartment fire experiments in a

compartment that is similar in size, geometry, and construction to the standard fire test compartment specified in the Uniform Building Code [11]1

. Results from 330 kW, 630 kW, and 980 kW

fires were used. In general, CFAST made predictions which were higher than the experimental

1The 1997 Uniform Building Code has been superceded by the International Building Code, 2003 Edition, International Code Council, Country Club Hills, Illinois.

17
results. In these cases, the temperature prediction is typically 20 % to 30 % higher than measured

values. Much of this can be attributed to not knowing the species production (soot) and relative

absorption of radiation by the gas layers which highlights the importance of scenario specification.

This is the most common cause of over prediction of temperature by CFAST. A secondary source

of discrepancy is correcting for radiation from thermocouple beads. The authors provide for this

correction, but the corrections cited are not as large as has been reported in other fire experiments

[12].

He et al. [13] describe a series of full-scale fire experiments that were designed to investigate

the validity of two zone models including CFAST version 3.1. The experiments, involving steady

state burning rates and a number of ventilation conditions, were conducted in a four-story building.

Temperature, pressure, flow velocity, smoke density and species concentrations were measured in

various parts of the building. The stack effect and its influence on temperature distribution in a

stair shaft were observed. Comparisons were then made between the experimental results and the

model predictions. Early in the fire there is a few percent difference2 between the predictions and

measurements; beyond 10 min, there are significant variations. Both the experiment and the model

are internally consistent; that is, higher flow leads to a higher interface height (figure 13 in the

paper). Once again, the difference is about 25 %. The authors discuss the effect of fuel composition

and correction for radiation from thermocouple beads but did not draw firm conclusions based on

their measurements of fuel products.

A series of experimental results for flaming fires, obtained using realistic fires in a prototype

apartment building were performed by Luo et al. [14]. Fuel configurations in the fire test included

a horizontal plain polyurethane slab, mock-up chair (polyurethane slabs plus a cotton linen cover),

and a commercial chair. CFAST version 3.1 typically over-predicted upper layer temperatures by

10 % to 50 % depending on the test conditions and measurement location in that test. The predicted and experimental time dependent upper layer temperatures were similar in shape. The time

to obtain peak upper layer temperatures was typically predicted to within 15 % of the experimental measurements. The authors concluded that CFAST was conservative in terms of life safety

calculations.

In order to optimize fire service training facilities, the best use of resources is imperative. The

work reported by Poole et al. [15] represents one aspect of a cooperative project between the

city of Kitchener Fire Department (Canada) and the University of Waterloo aimed at developing

design criteria for the construction of a fire fighter training facility. One particular criterion is that

realistic training with respect to temperature, heat release and stratification be provided in such a

facility. The purpose of this paper was to compare existing analytical heat release and upper and

lower gas temperature rise correlations and models with data from actual structures which were

instrumented and burned in collaboration with the Kitchener Fire Department. According to the

authors, the CFAST model was used ‘successfully’ to predict these conditions and will be used in

future design of such facilities.

A report by Bailey et al. [16] compares predictions by CFAST version 3.1 to data from

real scale fire tests conducted onboard ex-USS SHADWELL, the Navy’s R&D damage control

platform. The phenomenon of particular interest in this validation series was the conduction of

heat in the vertical direction through compartment ceilings and floors. As part of this work, Bailey et al. [17] compared CFAST temperature predictions on the unexposed walls of large metal

2Unless otherwise noted, percent differences are defined as (model-experiment)/experiment x100.

18
boxes, driven by steady state fires. This tested the models prediction of radiation and conduction

in both the vertical and horizontal directions. Indirectly it quantifies the quality of the conduction/convection/radiation models. The model and experiment compared well within measurement

error bounds of each. The comparison was particularly good for measurements in the fire compartment as well as for the compartment and deck directly above it, with predictions typically agreeing

with experiments within measurement uncertainty. The model under-predicted the temperatures of

the compartments and decks not directly adjacent to the fire compartment early in the tests. Most

of the error arose due to uncertainty in modeling the details of the experiment. The size of the vent

openings between decks and to the outside must be included, but these were not always known.

Cracks formed in the deck between the fire compartment and the compartment above due to the

intense fire in the room of origin, but a time dependent record was not kept. The total size of the

openings to the outside of warped doors in both compartments was not recorded. As can be seen

in figures 7 and 8 of reference [16], the steady state predictions are identical (within error bounds

of the experiment and prediction). The largest error is after ignition (uncertainty in the initial

fire) and during development of the cracks between the compartments. While this does not affect

the agreement in the room of origin, it does lead to an uncertainty of about 30 % in the adjacent

compartment.

4.2 Comparisons with Previously Published Test Data

A number of researchers have studied the level of agreement between computer fire models and

real-scale fires. These comparisons fall into two broad categories: fire reconstruction and comparison with laboratory experiments. Both categories provide a level of verification for the models

used. Fire reconstruction, although often more qualitative, provides a higher degree of confidence

for the user when the models successfully simulate real-life conditions. Comparisons with laboratory experiments, however, can yield detailed comparisons that can point out weaknesses in the

individual phenomena included in the models.

Deal [18] reviewed four computer fire models (CCFM [19], FIRST [20], FPETOOL [21] and

FAST [22] version 18.5 (the immediate predecessor to CFAST)) to ascertain the relative performance of the models in simulating fire experiments in a small room (about 12 m3

in volume) in

which the vent and fuel effects were varied. Peak fire size in the experiments ranged up to 800

kW. According to the author, all the models simulated the experimental conditions including temperature, species generation, and vent flows ‘quite satisfactorily.’ With a variety of conditions,

including narrow and normal vent widths, plastic and wood fuels, and flashover and sub-flashover

fire temperatures, competence of the models at these room geometries was ‘demonstrated.’

4.2.1 Fire Plumes

Davis compared predictions by CFAST version 5 (and other models) for high ceiling spaces [23].

In this paper, the predictive capability of two algorithms designed to calculate plume centerline

temperature and maximum ceiling jet temperature in the presence of a hot upper layer were compared to measurements from experiments and to predictions using CFASTs ceiling jet algorithm.

The experiments included ceiling heights of 0.58 m to 22 m and heat release rates of 0.62 kW

to 33 MW. When compared to the experimental results CFASTs ceiling jet algorithm tended to

19
over-predict the upper layer temperature by 20 %. With proper adjustment for radiation effects in

the thermocouple measurements, some of this difference disappears. The effect of entrainment of

the upper layer gases was identified for improvement.

4.2.2 Multiple Compartments

Jones and Peacock [24] presented a limited set of comparisons between the FAST model (version

18.5) and a multi-room fire test. The experiment involved a constant fire of about 100 kW in a

three-compartment configuration of about 100 m3. They observed that the model predicted an

upper layer temperature that was too high by about 20 % with satisfactory prediction of the layer

interface position. These observations were made before the work of Pitts et al. [12] showed that

the thermocouple measurements need to be corrected for radiation effects. Convective heating and

plume entrainment were seen to limit the accuracy of the predictions. A comparison of predicted

and measured pressures in the rooms showed within 20 %. Since pressure is the driving force for

flow between compartments, this agreement was seen as important.

Levine and Nelson [25] used a combination of full-scale fire testing and modeling to simulate a fire in a residence. The 1987 fire in a first-floor kitchen resulted in the deaths of three

persons in an upstairs bedroom, one with a reported blood carboxyhemoglobin content of 91 %.

Considerable physical evidence remained. The fire was successfully simulated at full scale in a

fully-instrumented seven-room two-story test structure. The data collected during the test have

been used to test the predictive abilities of two multiroom computer fire models: FAST and HARVARD VI. A coherent ceiling layer flow occurred during the full-scale test and quickly carried high

concentrations of carbon monoxide to remote compartments. Such flow is not directly accounted

for in either computer code. However, both codes predicted the carbon monoxide buildup in the

room most remote from the fire. Prediction of the pre-flashover temperature rise was also ‘good’

according to the authors. Prediction of temperatures after flashover that occurred in the room of

fire origin was seen as ‘less good.’ Other predictions of conditions throughout the seven test rooms

varied from ‘good approximations’ to ‘significant deviations’ from test data. Some of these deviations are believed to be due to combustion chemistry in the not upper layer not considered in detail

in either of the two models.

4.2.3 Large Compartments

Duong [26] studied the predictions of several computer fire models (CCFM, FAST, FIRST, and BRI

[27]), comparing the models with one another and with large fires (4 MW to 36 MW) in an aircraft

hanger (60 000 m3). For the 4 MW fire size, he concluded that all the models are ‘reasonably

accurate.’ At 36 MW, however, ‘none of the models did well.’ Limitations of the heat conduction

and plume entrainment algorithms were thought to account for some of the inaccuracies.

4.2.4 Prediction of Flashover

A chaotic event that can be predicted by mathematical modeling is that of flashover. Flashover is

the common term used for the transition a fire makes from a few objects pyrolyzing to full room

involvement. It is of interest to the fire service because of the danger to fire fighters and to building

20
designers because of life safety and the attendant impact on occupants. Several papers have looked

at the capability of CFAST to predict the conditions under which flashover can occur.

Chow [28] concluded that FAST correctly predicted the onset of flashover if the appropriate

criteria were used. The criteria were gas temperature near the ceiling, heat flux at the floor level

and flames coming out of the openings. This analysis was based on a series of compartment fires.

A paper by Luo et al. [29] presents a comparison of the results from CFAST version 3 against

a comprehensive set of data obtained from one flashover fire experiment. The experimental results

were obtained from a full-scale prototype apartment building under flashover conditions. Three

polyurethane mattresses were used as fuel. It was found that the predicted temperatures from

the CFAST fire model agreed well with the experimental results in most areas, once radiation

corrections are applied to the thermocouple data.

Collier [30] makes an attempt to quantify the fire hazards associated with a typical New Zealand

dwelling with a series of experiments. These tests, done in a three-bedroom dwelling, included

both non-flashover and flashover fires. The predictions by CFAST version 2 were seen by the

author as consistent with the experiments within the uncertainty of each.

Post-flashover fires in shipboard spaces have a pronounced effects on adjacent spaces due to

highly conductive boundaries. CFAST (version 3.1) predictions for the gas temperature and the

cold wall temperature were compared with shipboard fires [31]. The comparisons between the

model and experimental data show ‘conservative predictions’ according to the authors. The authors

attribute this to an overestimation of the average hot wall temperature and an underestimation of

external convective losses due to wind effects.

Finally, a comparison of CFAST with a number of simple correlations was used by Peacock

and Babrauskas [32, 33] to simulate a range of geometries and fire conditions to predict the development of the fire up to the point of flashover. The simulations represent a range of compartment

sizes and ceiling heights. Both the correlations and CFAST predictions were seen to provide a

lower bound to observed occurrence of flashover. For very small or very large compartment openings, the differences between the correlations, experimental data, and CFAST predictions was more

pronounced.

The important test of all these prediction methods is in the comparison of the predictions with

actual fire observations. Figure 4.1 (reference [33]) presents estimates of the energy required to

achieve flashover for a range of room and vent sizes. This figure is an extension of the earlier work

of Babrauskas [34] and includes additional experimental measurements from a variety of sources,

most notably the work of Deal and Beyler [35]. For a number of the experimental observations,

values are included that were not explicitly identied as being a minimum value at flashover. In

addition, figure 4.1 includes predictions from the CFAST model (version 5).

As with some of the experimental data defining flashover as an upper layer temperature reaching 600 ◦C, many experimental measures were reported as peak values rather than minimum values

necessary to achieve flashover. Thus, ideally all the predictions should provide a lower bound for

the experimental data. Indeed, this is consistent with the graph the vast majority of the experimental observations lie above the correlations and model predictions. For a considerable range in the

ratio AT /A

√

h, the correlations of Babrauskas [34] Thomas [36], and the MQH correlation of McCaffrey et al. [37] provide similar estimates of the minimum energy required to produce flashover.

The estimates of Hagglund [38] yields somewhat higher estimates for values of  ̈ AT /A

√

h greater

than 20 m−1/2

.

The results from the CFAST model for this single compartment scenario provide similar results

21
Figure 4.1: Comparison of correlations, CFAST predictions, and experimental data for the prediction of flashover in a compartment fire.

22
to the experiments and the correlations for most of the range of AT /A

√

h. For small values of

AT /A

√

h, the CFAST values rise somewhat above the values from the correlations. These small

values of AT /A

√

h result from either very small compartments (small AT ) or very large openings

(large AT /A

√

h), both of which stretch the limits of the assumptions inherent in the model. For very

small compartments, radiation from the fire to the compartment surfaces becomes more important,

enhancing the conductive heat losses through the walls. However, the basic two-zone assumption

may break down as the room becomes very small. For very large openings, the calculation of

vent flow via an orifice flow coefficient approach is likely inaccurate. Indeed, for such openings,

this limitation has been observed experimentally [34]. The estimates are close to the range of

uncertainty shown by the correlations which also diverge at very small values of AT /A

√

h.

Perhaps most significant in these comparisons is that all the simple correlations provide estimates similar to the CFAST model and all the models are consistent with a wide range of experimental data. For this simple scenario, little is gained with the use of the more complex models.

For more complicated scenarios, the comparison may not be as simple.

4.3 Comparison with Documented Fire Experience

There are numerous cases of CFAST being used to adjudicate legal disputes. Since these are

discussed in courts of law, there is a great deal of scrutiny of the modeling, assumptions, and

results. Most of these simulations and comparisons are not available in the public literature. A few

of the cases which are available are discussed below. The metric for how well the model performed

is its ability to reproduce the time-line as observed by witnesses and the death of occupants or the

destruction of property as was used in evidence in legal proceedings.

As mentioned in section 4.2.2, Levine and Nelson describe the use of FAST for understanding

the deaths of two adults in a residence in Sharon, Pennsylvania in 1987 [25]. The paper compared

the evidence of the actual fire, a full scale mockup done at NIST and the results from FAST (version

18) [39] and Harvard VI [40]. The most notable shortcoming of the models was the lower than

actual temperatures in the bedrooms, caused by loss of heat through the fire barriers. This led to

the improvement in CFAST in the mid-90s to couple compartments together so that both horizontal

and vertical heat transfer can occur to adjacent compartments.

Bukowski used CFAST version 3.1 to analyze a fire in New York City [41] in 1994 which

resulted in the death of three fire fighters. The CFAST model was able to reproduce the observed

conditions and supported the theory as to how the fire began and the cause of death of the three fire

fighters.

Chow describes the use and comparison of CFAST simulations with a 1996 high rise building fire in Hong Kong [42]. CFAST simulations were performed to help understand the probable

fire environment under different conditions. Three simulations were performed to study the consequences of a fire starting in the lift shaft. Smoke flow in the simulations qualitatively matched

those observed during the incident.

In the early morning hours of March 25,1990 a tragic fire took the lives of 87 persons at a

neighborhood club in the Bronx, New York [43]. The New York City Fire Department requested

the assistance of the NIST Center for Fire Research (CFR) in understanding the factors which

contributed to this high death toll and to develop a strategy that might reduce the risk of a similar

occurrence in the many similar clubs operating in the city. The simulation showed the potential for

23
development of untenable conditions within the club and particularly in the single exit stairway.

4.4 Comparison with Experiments Which Cover Special Situations

There are several sets of comparisons used in the development of the model or specific applications

beyond those discussed more generally above.

4.4.1 Nuclear Facilities

Floyd validated CFAST version 3.1 by comparing the modeling results with measurements from

fire tests at the Heiss-Dampf Reaktor (HDR) facility [44]. The structure was originally the containment building for a nuclear power reactor in Germany. The cylindrical structure was 20 m in

diameter and 50 m in height topped by a hemispherical dome 10 m in radius. The building was

divided into eight levels. The total volume of the building was approximately 11 000 m3. From

1984 to 1991, four fire test series were performed within the HDR facility. The T51 test series

consisted of 11 propane gas tests and three wood crib tests. To avoid permanent damage to the

test facility, a special set of test rooms were constructed, consisting of a fire room with a narrow

door, a long corridor wrapping around the reactor vessel shield wall, and a curtained area centered

beneath a maintenance hatch. The fire room walls were lined with fire brick. The doorway and

corridor walls had the same construction as the test chamber. Six gas burners were mounted in the

fire room. The fuel source was propane gas mixed with 10 % air fed at a constant rate to one of the

six burners.

In general, the comparison between CFAST and the HDR results was seen as ‘good’ by the

author, with two exceptions. The first is the over estimate of the temperature of the upper layer,

typically within about 15 % of the experimental measurements. This is common and generally

results from using too low a value for the production of soot, water (hydrogen) and carbon monoxide. The other exception consists of predictions in spaces where the zone model concept breaks

down, for example in the stairways between levels. In this case, CFAST has to treat the space

either in the filling mode (two layer approximation) or as a fully mixed zone (using the SHAFT

option). Neither is quite correct, and in order to understand the condition in such spaces in detail

(beyond the transfer of mass and energy), a more detailed CFD model must be used, for example,

FDS [45].

The U.S. Nuclear Regulatory Commission performed an extensive verification and validation

of several fire models commonly used in nuclear power plant applications [7]. These models included simple spreadsheet calculations, zone models (including CFAST [5]), and CFD models.

The results of this study are presented in the form of relative differences between fire model predictions and experimental data for fire modeling attributes such as temperature or heat flux that are

important to NPP fire modeling applications. These relative differences are affected by the capabilities of the models, the availability of accurate applicable experimental data, and the experimental

uncertainty of these data. Evaluation of the two-zone models showed that the models simulated the

experimental results within experimental uncertainty for many of the parameters of interest. The

reason for this may be that the relatively simple experimental configurations selected for this study

24
conform well to the simple two-layer assumption that is the basis of these models.

While the relative differences sometimes show agreement for many parameters, they also show

both under-prediction and over-prediction in some circumstances, most notably when conditions

vary within a compartment or detailed local conditions are important to accurate prediction (for

example, plume temperature or heat flux near to the fire source). The results and comparisons

included the the NRC study are included in this report for the current version of CFAST.

4.4.2 Small Scale Testing

As an implementation of the zone model concept, CFAST is applicable to a wide range of scenarios. One end of this spectrum are small compartments, one to two meters on a side. Several

research efforts have looked at small scale validation. There are three papers by Chow [46, 47, 48]

which examine this issue. The first is the use of an electric heater with adjustable thermal power

output was to verify temperature predictions by CFAST version 3.1. The second was closed chamber fires studied by burning four types of organic liquids, namely ethanol, N-heptane, and kerosene.

The burning behavior of the liquids was observed, and the hot gas temperature measured. These

behaviors along with the transient variations of the temperature were then compared with those

predicted by the CFAST model. Finally, in another series of experiments, three zone models, one

of which was CFAST, were evaluated experimentally using a small fire chamber. Once again,

liquid fires were chosen for having better control on the mass loss rate. The results on the development of smoke layer and the hot gas temperature predicted by the three models were compared

with those measured experimentally. According to Chow, ‘fairly good agreement’ was found if the

input parameters were carefully chosen.

4.4.3 Unusual Geometry and Specific Algorithms

A zone model is inherently a volume calculation. There is an assumption in the derivation of

the equations that gas layers are strongly stratified. This allows for the usual interpretation that

a volume can then be thought of as a rectangular parallelepiped, which allows the developers

to express the volume in terms of a floor area and height of a compartment, saying simply that

the height times the floor area is the volume. However, there are other geometries which can be

adequately described by zone models. Tunnels, ships, and attics are the most common areas of

application which fall outside of the usual scope.

Railway and Vehicle Tunnels

Altinakar et al. [49] used a modified version of CFAST for predicting fire development and smoke

propagation in vehicle or railroad tunnels. The two major modifications made to the model dealt

with mixing between the upper and lower layers and friction losses along the tunnel. The model

was tested by simulating several full-scale tests carried out at memorial Tunnel Ventilation Test

Program in West Virginia, and the Offeneg Tunnel in Switzerland. His article compares simulated

values of temperature, opacity and similar sensible quantities with measured values and discusses

the limits of the applicability of zone models for simulating fire and smoke propagation in vehicle

and railroad tunnels.

25
Peacock et al. [50] compared times to untenable conditions determined from tests in a passenger rail car with those predicted by CFAST for the same car geometry and fire scenarios. For a

range of fire sizes and growth rates, they found agreement that averaged approximately 13 %.

Non-Uniform Compartments

In January 1996, the U.S. Navy began testing how the CFAST model would perform when tasked

with predicting shipboard fires. These conditions include mass transport through vertical vents

(representing hatches and scuttles), energy transport via conduction through decks, improvement

to the radiation transport sub-model, and geometry peculiar to combat ships. The purpose of this

study was to identify CFAST limitations and develop methods for circumnavigating these problems

[51]. A retired ship representing the forward half of a USS Los Angeles class submarine was used

during this test. Compartments in combat ships are not square in floor area, nor do they have

parallel sides.

Application of CFAST to these scenarios required a direct integration of compartment crosssectional area as a function of height to correctly interpret the layer interface position and provide

correct predictions for flow through doors and windows (vertical vents). This required user specification of the area as a function of height (ROOMA and ROOMH inputs) to provide a description

for the model to use. For most applications of CFAST, the effort required for the input outweighs

any additional precision in the calculated results gained by use of the ROOMA and ROOMH inputs

in the model.

Long Corridors

Prior to development of the corridor flow model, the implementation of flow in compartments

assumed that smoke traveled instantly from one side of a compartment to another. The work of

Bailey et al. [52] provided the basis for the corridor flow model in CFAST. According to the author,

it shows ‘good agreement’ for the delay time calculated using CFAST version 5 and measured flow

along high aspect ratio passageways.

Mechanical Ventilation

There have been two papers which have looked at the effectiveness of the mechanical ventilation

system. The first considered a fire chamber of length 4.0 m, width 3.0 m and height 2.8 m with

adjustable ventilation rates [53]. Burning tests were carried out with wood cribs and methanol to

study the preflashover stage of a compartmental fire and the effect of ventilation. The mass loss rate

of fuel, temperature distribution of the compartment and the air intake rate were measured. The

heat release rates of the fuel were calculated and the smoke temperature was used as a validation

parameter. A scoring system was proposed to compare the results predicted by the three models.

According to the author, CFAST does ‘particularly well,’ though there are some differences which

can be attributed to the zone model approach.

A second series of experiments by Luo [54] indicate that the CFAST model (version 3.1) generally over predicts the upper layer temperature in the burn room because the two-zone assumption is

likely to break down in the burn room. It was found that the room averaged temperatures obtained

from CFAST were in ‘good overall agreement’ with the experimental results. The discrepancies

26
can be attributed to the correction needed for thermocouple measurements. The CO concentration,

however, was inconsistent. CFAST tended to overestimate CO concentration when the air handling system was in operation. This was seen due to inconsistencies in what is measured (point

measurements) and predicted (global measurements).

Sprinkler Activation

A suppression algorithm [55] was incorporated into CFAST. Chow [56] evaluates the predictive

capability for a sprinkler installed in an atrium roof. There were three main points being considered: the possibility of activating the sprinkler, thermal response, and water requirement. The zone

model CFAST was used to analyze the possibility of activation of a sprinkler head. Results derived from CFAST were seen to be ‘accurate, that is, providing good agreement with experimental

measurements.’

t

2 Fires

Matsuyama conducted a series of full-scale experiments [57] using t2 fires. Fire room and corridor

smoke filling processes were measured. The size of the corridors and arrangements of smoke

curtains were varied in several patterns. Comparisons were then made between the experimental

results and those predicted by CFAST. The author concludes that while the model does a ‘good

job’ of predicting experimental results, there are systematic differences which could be reduced

with some revision to zone model formulation to include the impact of smoke curtains.

27
28
Chapter 5

Description of Experiments

This chapter summarizes the range of experiments used in the current evaluation for the CFAST

model. This study focused on the predicted results of the CFAST fire model and did not include

an assessment of the user interface for the model. However, all input files used for the simulations

were prepared using the CFAST graphical user interface (GUI) and reviewed for correctness prior

to the simulations. The comparisons between the experiments and model predictions were characterized as semi-blind calculations, i.e., the modelers were given detailed descriptions of the test

conditions, test geometry, and fire source, but did not modify model inputs from these given conditions to improve model predictions. As such, the comparisons in this report provide an assessment

of the predictive capability of the model, but not an assessment of the ability of different modelers

to develop appropriate model inputs.

5.1 NBS Single Room Tests with Furniture

These data describe a series of room fire tests using upholstered furniture items in a room of fixed

size but with varying opening sizes and shapes [34] conducted by the National Bureau of Standards

(NBS, former name of NIST). It was selected for its well characterized and realistic fuel sources

in a simple single-room geometry. In addition, the wide variation in opening size should provide

challenges for current zone fire models. Peak fire size was about 2.9 MW with a total room volume

of 21 m3. A series of four single-room fire tests were conducted using upholstered furniture items

for comparison with their free burning behavior, previously determined in a furniture calorimeter.

The experiments were conducted in a single room enclosure; ventilation to the room was provided

by window openings of varying sizes. The room was equipped with an instrumented exhaust

collection system outside the window opening.

A second similar test series also utilized was a single-room fire test using furniture as the fire

source [58]. It expanded upon that data set by adding the phenomenon of wall burning. Peak fire

size was about 7 MW. The room size was similar to the first test series. Figure 5.1 illustrates the

configuration for the two test series.

The test furniture included a 28.3 kg armchair or a similar 40.0 kg love seat for the first test

series. Both were of conventional wood frame construction and used polyurethane foam padding,

made to minimum California State flammability requirements, and polyolefin fabric. A single

piece of test furniture and igniting wastebasket were the only combustibles in the test room.

29
T

T

H TVG

Fire source, specimen mass loss

Fire source, gas burner

Gas temperature array

Gas concentration (CO, CO , O )

Gas velocity array

2 2

T

G

V

Open

Vent

2.26 m

3.94 m

2.31 m 2.31 m 2.31 m

2.0 m

2.0 m

1.29 m

2.0 m

1.5 m 1.13 m

Figure 5.1: Plan and elevation view schematic of experimental room for NBS single room tests

with furniture. Note dotted lines on burning specimen indicates vertical surface for wall burning

experiments. Specimen and instrumentation placement are approximate.

For the second test series, room furnishings consisted of a 1.37 m wide x 1.91 m long x 0.53 m

high double bed, a 2.39 m X 0.89 m high headboard, and 0.51 m wide x 0.41 m deep x 0.63 m high

night table. Both headboard and night table were fabricated from 12.7 mm thick plywood. The

bedding was comprised of two pillows, two pillow cases, two sheets, and one blanket. The pillows

had a polypropylene fabric with a polyester filling. The pillow cases and sheets were polyestercotton. The blanket was acrylic material. The bedding was left in a ”slept in” condition which was

duplicated to the degree possible in each test. In all of the tests, the fire was started with match

flame ignition of a 0.34 kg (240 mm x 140 mm x 240 mm high) wastebasket, filled with 0.41 kg of

trash, positioned adjacent to the bed.

5.2 VTT Large Hall Tests

The experiments are described in reference [59]. The series consisted three unique fire scenarios

with replications for a total of 8 experiments. The experiments were undertaken to study the

movement of smoke in a large hall with a sloped ceiling. The tests were conducted inside the VTT

Fire Test Hall, with dimensions of 19 m high by 27 m long by 14 m wide. Figure 5.2 shows the

important features of the test hall. Figure 5.3 shows detailed plan, side and perspective schematic

diagrams of the experimental arrangement. Each test involved a single heptane pool fire, ranging

from 2 MW to 4 MW. Figure 5.4 is a photo of a 2 MW fire. Four types of measurements were

used in the present evaluation – the hot gas layer temperature and depth, average flame height and

the plume temperature. Three vertical arrays of thermocouples, plus two thermocouples in the

30
Figure 5.2: Cut-Away View of Case 2 of the VTT Large Hall Tests.

plume, were compared to model simulation results. The hot gas layer temperature and height were

reduced from an average of the three thermocouple arrays using a standard algorithm. The ceiling

jet temperature was not considered, because the ceiling in the test hall is not flat, and the model

algorithm is not appropriate for these conditions.

The VTT test report lacks some information needed to model the experiments, so some information was based on private communications with the principal investigator, Simo Hostikka.

Details used to conduct the model simulations is presented in reference [60], including information on the fire, the compartment, and the ventilation.

The walls and ceiling of the test hall consist of a 1 mm thick layer of sheet metal on top of a

5 cm layer of mineral wool. The floor was constructed of concrete. The report does not provide

thermal properties of these materials. Thermophysical properties of the materials that were used

in the simulations are given in table 5.1.

Table 5.1: Thermophysical Properties for VTT Large Hall Tests

Material Conductivity Specific Heat Density Thickness Emissivity

W/m◦C J/kg◦C kg/m3 m

Steel ICFMP BE2 54 425 7850 0.001 0.95

Concrete ICFMP BE2 2 900 230 0.15 0.95

In Cases 1 and 2, all doors were closed, and ventilation was restricted to leakage through the

building envelope. Precise information on air infiltration during these tests is not available. The

31
Figure 5.3: Plan, side and perspective schematic drawings of the experimental arrangement of the

VTT large hall fire tests, including the fuel pan

32
Figure 5.4: Photo of a 2 MW heptane fire during the VTT large hall tests. Photo provided by Simo

Hostikka, VTT.

scientists who conducted the experiments recommend a leakage area of about 2 m2, distributed

uniformly throughout the enclosure. By contrast, in Case 3, the doors located in each end wall

(Doors 1 and 2, respectively) were open to the external ambient environment. These doors are each

0.8 m wide by 4 m high, and are located such that their centers are 9.3 m from the south wall. The

test hall had a single mechanical exhaust duct, located in the roof space, running along the center

of the building. This duct had a circular section with a diameter of 1 m, and opened horizontally

to the hall at a distance of 12 m from the floor and 10.5 m from the west wall. Mechanical exhaust

ventilation was operational for Case 3, with a constant volume flow rate of 11 m3/s drawn through

the 1 m diameter exhaust duct.

Each test used a single fire source with its center located 16 m from the west wall and 7.4 m

from the south wall. For all tests, the fuel was heptane in a circular steel pan that was partially

filled with water. The pan had a diameter of 1.17 m for Case 1 and 1.6 m for Cases 2 and 3. In each

case, the fuel surface was 1 m above the floor. The trays were placed on load cells, and the HRR

was calculated from the mass loss rate. For the three cases, the fuel mass loss rate was averaged

from individual replicate tests. In the HRR estimation, the heat of combustion (taken as 44.6 kJ/g)

and the combustion efficiency for n-heptane was used. In this report, a combustion efficiency of

0.85 ± 0.12 (or ± 14 %) was used for the VTT pool fire tests [60]. Due to the relatively large value

of the uncertainty associated with the combustion efficiency the uncertainty in HRR is dominated

by the uncertainty in the combustion efficiency. Uncertainty in the mass loss rate measurement

also contributed to the overall uncertainty, and the uncertainty in HRR was estimated as 15 % [60].

Figure 5.5 show the prescribed HRR as a function of time during Cases 1 to 3, respectively. The

33
radiative fraction was assigned a value of 0.35 [60], similar to many smoky hydrocarbons [61]. The

relative combined expanded (2σ) uncertainty in this parameter was assigned a value of ± 20 %,

which is typical of uncertainty values reported in the literature for this parameter. Further details

of the model inputs used for these simulations are included in reference [60].

5.3 NIST/NRC Test Series

These experiments, sponsored by the US NRC and conducted at NIST, consisted of 15 largescale experiments performed in June 2003. All 15 tests were included in the validation study.

The experiments are documented in Ref. [62]. The fire sizes ranged from 350 kW to 2.2 MW in a

compartment with dimensions 21.7 m by 7.1 m by 3.8 m high, designed to represent a compartment

in a nuclear power plant containing power and control cables. A photo of the fire seen through the

compartment doorway is shown in figure 5.6. Figure 5.7 shows the important features of the test

hall. Figure 5.8 shows detailed plan, side and perspective schematic diagrams of the experimental

arrangement. The walls and ceiling were covered with two layers of marinate boards, each layer

0.0125 m thick. The floor was covered with one layer of gypsum board on top of a layer of

plywood. Thermo-physical and optical properties of the marinate and other materials used in the

compartment are given in reference [62]. The room had one door and a mechanical air injection and

extraction system. Ventilation conditions, the fire size, and fire location were varied. Numerous

measurements (approximately 350 per test) were made including gas and surface temperatures,

heat fluxes and gas velocities. Detailed schematic diagrams of the experimental arrangement are

shown in figure 5.8. Table 5.2 shows the experimental conditions for all 15 tests.

The compartment had a 2 m by 2 m door in the middle of the west wall. Some of the tests had

a closed door and no mechanical ventilation, and in those tests the measured compartment leakage

was an important consideration. Reference [62] reports leakage area based on measurements performed periodically during the test series. For the closed door tests, the leakage area used in the

simulations was based on the last available measurement. It should be noted that the chronological

order of the tests differed from the numerical order [62].

The mechanical ventilation and exhaust was used during some test, providing about 5 air

changes per hour. The supply duct was positioned on the long wall, about 2 m off the floor.

An exhaust duct of equal area to the supply duct was positioned on the opposite wall at a comparable location. The flow rates through the supply and exhaust ducts were measured in detail during

breaks in the testing, in the absence of a fire. During the tests, the flows were monitored with single

bi-directional probes during the tests themselves.

A single nozzle was used to spray liquid hydrocarbon fuels onto a 1 m by 2 m fire pan that was

about 0.02 m deep. The test plan originally called for the use of two nozzles to provide the fuel

spray. Experimental observation suggested that the fire was more steady with the use of a single

nozzle. In addition, it was observed that the actual extent of the liquid pool was well-approximated

by a 1 m circle in the center of the pan. For safety reasons, the fuel flow was terminated when

the lower-layer oxygen concentration dropped to approximately 15 % by volume. The fuel used in

14 of the tests was heptane, while toluene was used for one test. The HRR was determined using

oxygen consumption calorimetry (figure 5.9 shows a sample heat release rate for one of the tests

in the series). The recommended uncertainty values for HRR were 17 % for all of the tests. The

radiative fraction was measured in an independent study for the same fuels using the same spray

34
Figure 5.5: Prescribed Heat Release Rate as a Function of Time for VTT Large Hall Tests.

35
Figure 5.6: Photograph of a 1 MW heptane fire seen through the open doorway. Photo provided

by Anthony Hamins, NIST.

Figure 5.7: Cross-section View of the NIST NRC Test Configuration.

36
Figure 5.8: Plan, side and perspective schematic drawings of the NIST NRC experimental arrangement. The fuel pan and cables B, D, F, and G (dotted lines) are also shown.

37
Table 5.2: Test Matrix and Experimental Conditions for NIST NRC Tests

Test Nominal Peak Cable Fuel; Burner Location Door Mechanical

Q ̇ (MW) Type Ventilation

1 0.35 XPEa Heptane; Center Closed Off

2 1 XPE Heptane; Center Closed Off

3 1 XPE Heptane; Center Open Off

4 1 XPE Heptane; Center Closed On

5 1 XPE Heptane; Center Open On

6 Not Conducted

7 0.35 PVCb Heptane; Center Closed Off

8 1 XPE Heptane; Center Closed Off

9 1 XPE Heptane; Center Open Off

10 1 PVC Heptane; Center Closed On

11 Not Conducted

12 Not Conducted

13 2 XPE Heptane; Center Closed Off

14 1 XPE Heptane; 1.8 m from N wall Open Off

on E-W centerline

15 1 PVC Heptane; 1.25 m from S wall Open Off

on E-W centerline

16 2 PVC Heptane; Center Closed On

17 1 PVC Toluene; Center Closed Off

18 1 XPE Heptane; 1.55 m from S wall Open Off

1.50 m E of centerline

a - XPE cable has crosslinked polyethylene jacket insulation

b - PVC cable has a polyvinylchloride jacket insulation

38
Figure 5.9: Measured and prescribed heat release rate as a function of time during Test 3 of the

NIST NRC test series

burner as used in the test series [63]. The value of the radiative fraction and its uncertainty were

reported as 0.44 ± 16 % and 0.40 ± 23 % for heptane and toluene, respectively. Further details of

the model inputs used for these simulations are included in reference [60].

5.4 FM/SNL Test Series

The Factory Mutual and Sandia National Laboratories (FM/SNL) Test Series was a series of 25

fire tests conducted in 1985 for the NRC by Factory Mutual Research Corporation (FMRC), under

the direction of Sandia National Laboratories (SNL). The primary purpose of these tests was to

provide data with which to validate computer models for various types of NPP compartments. The

experiments were conducted in an enclosure measuring 18 m x 12 m x 6 m, constructed at the

FMRC fire test facility in Rhode Island. Figure 5.10 shows detailed schematic drawings of the

compartment from various perspectives. The FM/SNL test series is described in detail, including

the types and locations of measurement devices, as well as some results in References [64, 65].

All of the tests involved forced ventilation to simulate typical nuclear power plant installation practices. Four of the tests were conducted with a full scale control room mockup in place.

Parameters varied during the experiments included fire HRR, enclosure ventilation rate, and fire

location.

Data from three of these experiments (Tests 4, 5, and 21) were used since these tests were

documented far more completely than other tests in the series. In these tests, the fire source was

a 0.91 m diameter propylene gas burner. For Tests 4 and 5, the burner was centered along the

longitudinal axis centerline, 6.1 m laterally from the nearest wall, and the burner rim was located

approximately 0.1 m above the floor. For Test 21, the fire source was placed within a simulated

benchboard electrical cabinet.

The value of heat release rate was determined using oxygen consumption calorimetry in the

exhaust stack with a correction applied for the CO2 in the upper layer of the compartment. The

uncertainty of the fuel mass flow was not documented. All three tests selected for this study had

the same target peak heat release rate of 516 kW. A 4 min t-squared growth profile preceded the

39
Figure 5.10: Detailed plan, side, and perspective schematic drawings of the FM/SNL experimental

arrangement, including the supply and exhaust ducts, and the fuel pan.

40
Figure 5.11: Prescribed (dotted line) and measured (solid line) heat release rate as a function of

time during Test 21 of the FM/SNL test series

target heat release rate. The test report contains time histories of the measured heat release rate,

for which the average sustained heat release rate following the ramp up for Tests 4, 5, and 21

have been estimated as 510 kW, 480 kW, and 470 kW, respectively. Once reached, the peak heat

release rate was maintained essentially constant during a steady burn period of 6 min in Tests

4 and 5, and 16 min in Test 21. Figure 5.11 shows the specified and the measured [64] heat

release rate as a function of time during Test 21 of the FM/SNL test series. The specified curves

are used in the model calculations rather than the measured time-dependent curves, because the

fuel flow was maintained a constant and fluctuations in the heat release rate are expected from

calorimetry measurements. Also, there was some concern with the quality of the heat release rate

measurement as the test report notes that during Tests 4, 5, and 21 there was a downward bias in

the measured values due to significant loss of effluent from the exhaust hood. This bias was treated

as an additional uncertainty, and the relative combined expanded uncertainty was assumed to equal

± 20 % [60], which is somewhat larger than typical calorimetric measurement uncertainty. The

radiative fraction was not measured during the experiment, but in this study it is assumed to equal

0.35, which is typical for a smoky hydrocarbons [66, 67]. The expanded uncertainty in this value

was taken as ± 20 % [60], a value typical of reported uncertainty [63, 61]. It was further assumed

that the radiative fraction was about the same in Test 21 as the other tests, as fuel burning occurred

outside of the electrical cabinet in which the burner was placed.

Four types of measurements were conducted during the FM/SNL test series that are used in the

current model evaluation study, including the hot gas layer temperature and depth, and the ceiling

jet and plume temperatures. Aspirated thermocouples were used to make all of the temperature

measurements. Generally, aspirated thermocouple (TC) measurements are preferable to bare-bead

TC measurements, as systematic radiative exchange measurement error is reduced [60]. For the

relatively low temperatures observed (<100 ◦C), however, the differences are expected to be small

[60].

Aspirated thermocouple measurements for the range of temperatures measured are typically

accurate to a few degrees (◦C) [60]. The temperatures were measured using the aspirated thermocouples in Sectors 1, 2 and 3 of the compartment. In addition, there were some near-ceiling TCs

placed directly above the burner in Tests 4 and 5.

41
Data from all of the vertical thermocouple trees were used when reducing the HGL height and

temperature. For the FM/SNL Tests 4 and 5, Sectors 1, 2, and 3 were used, all weighted evenly

[60]. For Test 21, Sectors 1 and 3 were used, evenly weighted. Sector 2 was partially within the

fire plume in Test 21 and was not used in the calculation of hot gas layer temperature [60].

5.5 iBMB Compartment Tests

A series of small compartment kerosene pool fire experiments, conducted at the Institut fr Baustoffe,

Massivbau und Brandschutz (iBMB) of Braunschweig University of Technology in Germany in

2004 [68]. The results from Test 1 were considered here. These experiments involved relatively

large fires in a relatively small (3.6 m x 3.6 m x 5.7 m) concrete enclosure. Figure 5.12 shows plan,

side and perspective schematic drawings of the experimental arrangement, including the location

of the fuel pan, which was located at the center of the compartment.

Only a portion of Test 1 was selected for consideration in the present study, because a significant amount of data was lost in Test 2, and the measured Q ̇ during Test 3 exhibited significant

amounts of fluctuation. Five types of measurements that were conducted during the test series

were used in the model evaluation reported here. These included the HGL temperature and depth,

the temperature of targets and compartment surfaces, and heat flux. In addition, figure 5.13 shows

the heat release rate for Test 1, which was estimated from a mass loss rate measurement. In this

calculation, the heat of combustion and the combustion efficiency were taken as 42.8 MJ/kg and 1,

respectively, as suggested by Refs. [60, 69]. There were several reported difficulties in measuring

the mass loss rate, including data loss due to an instrument malfunction and significant fluctuations

in the measured mass loss rate. Due to these measurement issues and because the combustion efficiency was not well-characterized, the Q ̇ uncertainty was assigned a relatively large expanded

uncertainty of ± 25 % [60].

A second series of fire experiments in 2004, conducted under the International Collaborative

Fire Model Project (ICFMP) involved realistically routed cable trays inside the same concrete enclosure at iBMB [69]. The compartment was configured slightly differently with a ceiling height

of 5.6 m. A schematic diagram from plan, side, and perspective views of the experimental arrangement is shown in figure 5.14. Six types of measurements conducted during the test series

were used in the evaluation conducted here, including the HGL temperature and depth, oxygen gas

concentration, the temperature of targets and compartment surfaces, and heat flux.

The results of four tests were available, of which one has been used in the current study. These

tests were conducted primarily for the evaluation of cable ignition and flame spread. The results

were erratic, and no replicate experiments were performed. Given the primitive nature of the

ignition and spread algorithms within the models, it was decided that only a qualitative analysis

would be possible with the data from three of the four experiments. However, in one experiment,

the first 20 minutes involved a fairly well-characterized ethanol pool fire burning on the opposite

side of the compartment from the cable tray. This part of the experiment has been used as part of

the model evaluation.

The first part of the test consisted of preheating the cable trays in the room with a 1 m2round

pan on the floor filled with ethanol (ethyl alcohol) used as the preheating source. At 30 min, a

propane gas burner was used as the fire source this was not considered because only the first 20

min of the test was used in this validation study. Exhaust products were collected in an exhaust

42
Figure 5.12: Detailed plan, side, and perspective schematic drawings of the iBMB pool fire experimental arrangement.

43
Figure 5.13: Estimated heat release rate for the iBMB fire experiments.

duct and the Q ̇ was measured using the oxygen calorimetry. For the purpose of this study, the

measured Q ̇ was used as direct input to the various fire models. The first 20 min of data were

used for the model evaluation. After 20 min, the Q ̇ became relatively noisy. Figure 5.13 shows

the HRR. The relative combined expanded uncertainty was assigned a value of ±15 %, consistent

with typical values of this parameter [60].

5.6 NBS Multi-Compartment Test Series

The National Bureau of Standards (NBS, former name of NIST) Multi-Compartment Test Series

consisted of 45 fire tests representing 9 different sets of conditions were conducted in a three-room

suite. The experiments were conducted in 1985 and are described in detail in reference [70]. The

suite consisted of two relatively small rooms, connected via a relatively long corridor. Total volume

of the structure was approximately 100 m2. The fire source, a gas burner, was located against the

rear wall of one of the small compartments as seen in Figure 5.15 for a 100 kW fire. Figures 5.16

and 5.17 presents the experimental arrangement in the form of plan, side and perspective schematic

drawings of the compartments. Fire tests of 100 kW, 300 kW and 500 kW were conducted. For the

current study, three 100 kW fire experiments have been used, including Test 100A from Set 1, Test

100O from Set 2, and Test 100Z from Set 4. For the NBS Multi-room series, Tests 100A, 100O

and 100Z were selected for study, because they were constructively used in a previous validation

study [[71], and because these tests had the steadiest values of measured heat release rate during

the steady burning period. The selected data are also available in Reference [71]. Reference [60]

provides information used as model input for simulation of the NBS tests, including information

on the compartment, the fire, the ventilation, and ambient conditions. The data in the NBS data

set was acquired every 10 s with a 6 s time-average. This time-averaging interval was somewhat

smaller than all of the other experimental series, which were time-averaged over a 10 s interval.

44
Figure 5.14: Detailed plan, side, and perspective schematic drawings of the iBMB cable fire experimental arrangement.

45
Figure 5.15: Photo of a 100 kW fire with the burner located against the rear wall of one of the

small compartments in the NBS Multi-Compartment test Series.

Figure 5.16: Overview of the NBS Test Configuration.

46
Figure 5.17: Plan, side and perspective schematic drawings of the NBS experimental arrangement,

including the burner.

47
Figure 5.18: Prescribed and measured heat release rate as a function of time during Tests 100A

and 100Z of the NBS multi-room test series.

Figures 5.18 show the experimentally measured Q ̇ as a function of time during Tests 100A

and 100Z, respectively, of the NBS multi-room test series, typically averaging about 100 kW. In

these two tests, for which the door was open, the Q ̇ during the steady burning period measured

via oxygen consumption calorimetry was about 110 kW ± 17 kW (± 15 %) [60]. The combined

relative expanded (2σ) uncertainty in the calorimetric Q ̇ is assigned a value of ± 15 %, consistent

with the replicate measurements made during the experimental series and the uncertainty typical of

oxygen consumption calorimetry [60]. This value is also consistent with the measurement variation

evident in the figures. It was assumed that the closed door test (Test 100O) had the same Q ̇ as the

open door tests [60].

The specified or prescribed Q ̇ is also shown in the figures. The mass flow of the fuel (natural

gas in Test 100A, or natural gas mixed with acetylene in Tests 100O and 100Z) was not metered;

rather, the effluent was captured in a hood mounted above the open door in the corridor and the

was measured using oxygen consumption calorimetry. The manner by which the fuel flow was

controlled is not documented. In Test 100A, candles were used to increase smoke in the upper

layer to promote visualization. In Tests 100O and 100Z, acetylene was used (about 20 % by

volume) to produce smoke. In those tests, the flow of natural gas and acetylene were adjusted to

obtain approximately the same Q ̇ as in Test 100A. The addition of acetylene increased the radiative

fraction of the fire.

For practical reasons, piped natural gas supplied by large utility companies is often used in fire

experiments. While its composition may vary from day to day, there is little change expected in the

value of the radiative fraction [60]. As mentioned above, natural gas was used as the fuel in Test

100A. In Tests 100O and 100Z, acetylene was added to the natural gas to increase the smoke yield,

and as a consequence, the radiative fraction increased. The radiative fraction of natural gas has

been studied previously, whereas the radiative fraction of the acetylene/natural gas mixture has not

been studied. The radiative fraction for the natural gas fire was assigned a value of 0.20, whereas

a value of 0.30 was assigned for the natural gas/acetylene fires [60, 61].

The relative combined expanded (2σ) uncertainty in this parameter was assigned a value of

± 20 % in Test 100A and ± 30 % in 100O and 100Z. The 20 % expanded deviation value is

consistent with typical values of the deviation reported in the literature for the measured radiative

48
fraction. The 100O and 100Z tests had a 50 % larger value assigned, because the effect on the

radiative fraction of adding acetylene to the natural gas was not measured [60].

Measurements made during the NBS test series included gas and surface temperature, pressure, smoke and major gas species concentration, and doorway gas velocity. Only two types of

measurements conducted during the NBS test series were used in the evaluation considered here,

because there was less confidence in the other measurements. The measurements considered here

were the HGL temperature and depth, in which bare bead thermocouples were used to make these

measurements. Single point measurements of temperature within the burn room were not used

in the evaluation of plume or ceiling jet algorithms. This is because, in neither instance, was the

geometry consistent with the assumptions used in the model algorithms of plumes or jets. Specifically, the burner was mounted against a wall, and the room width to height ratio was less than that

assumed by the various ceiling jet correlations.

5.7 FM Four Room Including Corridor Test Series

This data set describes a series of tests conducted in a multiple room configuration with more

complex gas burner fires than the previous data set. This study [72] was included because, in many

ways, it is similar to the smoke movement study performed at NBS [70], and permits comparisons

between two different laboratories. In addition, it expands upon that data set by providing larger

a time-varying gas burner fires in a room-corridor configuration. Fire size was about up to 1 MW

with a total volume of 200 m3.

This study was performed to collect data allowing for variations in fire source, ventilation, and

geometry in a multi-compartment structure, especially for situations with closed doors. This test

program was carried out at Factory Mutual Research Corporation (FMRC) in West Glocester, RI,

in which 60 fire experiments were conducted in a multiple-room enclosure to furnish validation

data for theoretical fire models.

Figure 5.19 shows a diagram of the basic facility with indications of instrumentation location.

The facility was built on the floor of FMRC’s fire test building, using part of the 67 m by 76 m test

building where the ceiling height is 18.3 m. The layout in figure 25 shows a burn room and two

target rooms connected to a corridor. The corridor was 2.43 m wide x 18.89 m long x 2.43 m high.

The burn room measured 3.63 m deep x 3.64 m wide x 2.45 m high; a sealable window opening,

measuring 0.85 m square, was centered on the rear wall, 0.34 m down from the top, and a door,

measuring 0.92 m by 2.05 m high, was centered on the front wall (opening to the corridor). For

closed window experiments, the wood-framed calcium silicate board window cover was pressed

against a bead of caulking around the steel window frame and held by drop bars positioned into

slots on the outside wall.

Room 3, located opposite the burn room, measured 3.65 m deep x 3.64 m wide x 2.45 m high;

a door, measuring 0.88 m by 2.02 m high, was centered on the front wall (opening to the corridor).

Room 4, located at the opposite end of the corridor, measured 3.65 m deep x 3.65 m wide x 2.43 m

high and had a 0.88 m by 2.02 m high door centered on the front wall (opening to the corridor); an

observation alcove, measuring 1.28 m by 0.86 m by 1.99 m high, was located in the front corner of

room 4. Each room was equipped with a 102 mm inside diameter vent tube with a 61 mm inside

diameter orifice meter and thermocouple, with option of exhaust fan (tube centered 0.27 m from

the floor and 0.17 m from the closest parallel wall). An inlet vent (0.29 m2

) used with exhaust fans

49
TGS

TGS

TT SS TT GS S

TT GS S

TT SS

V

V

V

IV

T

T

G

S

V

IV

S

Fire source, gas burner

Gas temperature array

Surface temperature (ceiling)

Gas concentration

Smoke obscuration

Differential pressure array

Vent tube (102 mm ID) fan

Inlet vent used with exhaust fans (0.27 m ) 2

Figure 5.19: Overview of the Factory Mutual Four Room test series.

was centered 0.43 m above the floor at the end of the corridor between the burn room and room 3.

When not in use, the inlet vent was sealed with a gypsum board cover taped in place.

The target room doors were commercial fire doors (wood-faced composite doors with calcium

silicate cores, 14 h rated) mounted on 16 gage steel frames. The burn room door was fabricated

from 12.7 mm calcium silicate, mounted in a steel frame lined with calcium silicate. Details of the

doors and the spacings (cracks) are given in the original reference [72].

Gypsum wallboard, 12.7 mm thick, on wood studs was used throughout the experimental facility. In addition, the walls and ceiling of the burn room were overlaid with calcium silicate, also

12.7 mm thick, to harden against repeated fire exposure. The existing concrete floor of the test

building was used.

Two types of fire sources were used: 1) steady propylene fires at 56 kW on a 0.30 m diameter

sand burner and 522 kW on a 0.91 m diameter burner and 2) propylene fires on the 0.91 m diameter

burner programmed under computer control to grow with the square of time, exceeding 1 MW in

1, 2, 4, or 8 min.

The 0.91 m diameter, 0.58 in high propylene burner was used for most of the tests. Its design

consisted of a 12 gage steel container with a gas distributor near the bottom, filled with gravel to

a 67 percent height, where there was wire mesh screen, and coarse sand to the full height of the

burner. The 0.30 m diameter burner was a scaled-down version of similar design.

5.8 NIST Seven-story Hotel Tests

By far the most complex test, this data set is part of a series of full-scale experiments conducted

to evaluate zoned smoke control systems, with and without stairwell pressurization [73]. It was

conducted in a seven story hotel with multiple rooms on each floor and a stairwell connecting all

floors. This data set was chosen because it would challenge the scope of most current fire models.

Measured temperatures and pressure differences between the rooms and floors of the building are

extensive and consistent. Peak fire size was 3 MW with a total building volume of 140 000 m3

.

Smoke movement and the performance of smoke control systems were studied in a seven story

50
T T

T

T

T

G

S

Fire source, gas burner

Gas temperature array

Gas concentration

Smoke obscuration

Differential pressure (2nd floor hallway to stairway

and 2nd floor hallway ceiling to 3rd floor

TGS

Supply

fan on

1st and 3rd

floors

Exhaust fan on 2nd floor

Elevator

Ground Level

Open Exterior

Door

Stairwell

Supply

4.25 m /s 3

7th floor

6th floor

5th floor

4th floor

3rd floo r (pressurized at 6 air changes per hour)

2nd floor (exhausted at 6 air changes per hour)

Ground floor (pressurized at 6 air changes per hour)

Basement

Figure 5.20: Overview of the NIST Seven-story hotel test series including smoke control.

hotel building with smoke generated from wood fires and theatrical smoke. A total of 12 single

experiments were conducted under a variety of conditions: two different fire sizes; sprinklered vs

non-sprinklered wood fires; zoned smoke control on or off; stairwell pressurization on or off; with

and without ventilation to the outside; and open and closed doors.

The Plaza Hotel building was a masonry structure consisting of two wings, one three stories

and the other seven stories tall. The two wings were built at different times. The wings were

connected to each other at only one location on each floor. The connections between the wings

at each floor were sealed off, and the fires were set on the second floor of the seven-story wing,

using the shorter wing as an instrumentation area. Areas of the second floor were fire hardened to

minimize structural damage to the building.

The smoke control systems were designed using the methods presented in the smoke control

manual of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers [74],

and the design analysis is discussed in detail by Klote [75]. The minimum design pressure difference was 25 Pa, meaning that the system should be able to maintain at least this value without a

fire. The Plaza Hotel building had no central forced air heating, ventilating, and air-conditioning

(HVAC) system, so a dedicated system of fans and ducts was installed for zoned smoke control and

stairwell pressurization. The smoke control system consisted of the three 0.944 m3

/s centrifugal

fans shown in 5.20, plus another centrifugal fan (not shown) located outside and supplying 4.25

m3/s of pressurization air to the stairwell at the first floor. The smoke control system is illustrated

in figure 5.20. All the test fires were located in the second floor smoke zone. This smoke was exhausted at about six air changes per hour. The first and second floors were pressurized at about six

air changes per hour. When the stairwell pressurization system was activated, the exterior stairwell

door was open. This approach is intended to minimize fluctuations due to opening and closing

doors.

51
52
Chapter 6

Hot Gas Layer Temperature and Depth

CFAST simulated all of the chosen experiments. Details of the comparisons with experimental

data, are provided in Appendix A. The results are organized by quantity as follows:

• hot gas layer (HGL) temperature and height

• ceiling jet temperature

• plume temperature

• flame height

• oxygen and carbon dioxide concentration

• smoke concentration

• compartment pressure

• radiation heat flux, total heat flux, and target temperature

• wall heat flux and surface temperature

Comparisons of the model predictions with experimental measurements are presented as relative differences. The relative differences are calculated as follows:

ε =

∆M −∆E

∆E

=

(MP − M0)−(EP −E0)

(EP −E0)

(6.1)

where ∆M is the difference between the peak value (MP) of the evaluated parameter and its

original value (M0), and ∆E is the difference between the experimental observation (EP) and its

original value (E0).

The measure of model accuracy used throughout this study is related to experimental uncertainty. Reference [60] discusses this issue in detail. In brief, the accuracy of a measurement, for

example, a gas temperature, is related to the measurement device, a thermocouple. In addition,

the accuracy of the model prediction of the gas temperature is related to the simplified physical

description of the fire and the accuracy of the input parameters, especially the specified heat release rate. Ideally, the purpose of a validation study is to determine the accuracy of the model in

53
the absence of any errors related to the measurement of both its inputs and outputs. Because it is

impossible to eliminate experimental uncertainty, at the very least a combination of the uncertainty

in the measurement of model inputs and output can be used as a yardstick. Dotted lines in figure

6.1 show this combined uncertainty estimate for HGL temperature and layer depth. Corresponding estimates are included for other quantities in later sections. If the numerical prediction falls

within the range of uncertainty attributable to both the measurement of the input parameters and

the output quantities, it is not possible to further quantify its accuracy. At this stage, it is said that

the prediction is within experimental uncertainty.

Note that the calculation of relative difference is based on the temperature rise above ambient,

and the layer depth, that is, the distance from the ceiling to where the hot gas layer descends. Where

the model over-predicts the HGL temperature or the depth of the HGL, the relative difference is

a positive number. This convention is used throughout this report where the model over-predicts

the severity of the fire, the relative difference is positive; where it under-predicts, the difference is

negative.

Arguably the most frequent question asked about a fire is, How hot did it become? Temperature in the upper layer of a compartment is an obvious indicator to answer this question. Peak

temperature, time to peak temperature, or time to reach a chosen temperature tenability limit are

typical values of interest. Quality of the prediction (or measurement) of layer interface position is

more difficult to quantify. Although observed in a range of experiments, the two-layer assumption

is in many ways just a convenience for modeling. In experimental measurements, temperature is

typically measured with an array of thermocouples from floor to ceiling. This floor to ceiling temperature profile can then used to estimate a hot gas layer height and the temperature of the upper

and lower gas layers [76] [77] consistent with the two-zone assumption. Appendix A provides

details of the calculation.

From a standpoint of hazard, time of descent to a chosen level may be a reasonable criterion

(assuming some in the room will then either be forced to crawl beneath the interface to breathe

the clean atmosphere near the floor or be forced to breath the upper layer gases). Minimum values

may also be used to indicate general agreement. For the single-room tests with furniture or wallburning, these are appropriate indicators to judge the comparisons between model and experiment.

For the more-closely steady-state three- and four-room tests with corridor or the multiple-story

building tests, a steady-state average may better characterizes the nature of the experiment.

A good prediction of the HGL height is largely a consequence of a good prediction of its

temperature because smoke and heat are largely transported together and most numerical models

describe the transport of both with the same type of algorithm. Typically, CFAST slightly overpredicts the HGL temperature, most often within experimental uncertainty. Hot gas layer height

is typically within experimental uncertainty for well-ventilated tests and near floor level for underventilated tests where compartments are closed to the outside. For HGL height, only values from

open-door tests are included. For closed-door tests, visual observations typically show that the

HGL fills the entire compartment volume from floor to ceiling, inconsistent with the calculated

results for the experimental data. Thus, the calculated experimental values of HGL height for

closed-door tests are not seen as appropriate for comparison to model results.

54
6.1 Model / Experiment Comparisons

Figure 6.1 shows a comparison of predicted and measured values for HGL temperature and depth.

Appendix A provides individual graphs of model and experimental values and tables of peak values

and relative differences.

Following is a summary of the accuracy assessment for the HGL predictions of the test series:

NBS Single Room Tests with Furniture

For two of the four tests (Tests F1 and F6, tests with a single furniture item in the compartment),

the HGL temperature and depth for these tests were calculated separately for two different thermocouple arrays, one located in the front of the compartment and one in the rear. For the other two

tests (tests W1 and W2, tests with furniture and a wood wall surface), a single thermocouple array

was available.

For the single-room tests, predicted temperatures and layer interface position show obvious

similarities to the measured values. Peak values occurred at similar times with comparable rise

and fall for most comparisons. Interface height for the single-room with wall-burning is a notable

exception. Unlike the model prediction, the experimental measurement did not show the rise and

fall in concert with the temperature measurement. Peak values were typically higher for upper

layer temperature and lower for lower layer temperature and layer interface position.

For the furniture tests, the agreement ranges from a relative difference of -30 % to 8 %. The

agreement is quite different for the two arrays in each test. Table 6.1 shows the relative differences

for tests F1 and F6. For both the layer temperature and layer depth, the difference between the

model and experiment changes depending on the measurement location. In the same tests (F1)

the values are well within experimental uncertainty at one location and outside for the other. For

test F6, this varies from -30 % to 8 % for the temperature and from -19 % to 26 % for the layer

depth. For these tests with a post-flashover fire in a small compartment, clearly the assumption of a

uniform upper layer is questionable. Curve shape for the experimental data and model predictions

is quite similar.

Table 6.1: Relative Difference for HGL Temperature and Depth for Two Measurement Locations

in Two Single-Room Tests

Test Location Temperature Layer Depth

% %

F1 A -5 -5

B -19 -12

F6 A 8 -19

B -30 26

VTT Large Hall Test Series

The HGL temperature and depth were calculated from the averaged gas temperatures from three

vertical thermocouple arrays. Ten thermocouples in each vertical array, spaced 2 m apart in the

55
Figure 6.1: Comparison of Measured and Predicted HGL Temperature and Height.

56
lower two-thirds of the hall, and 1 m apart near the ceiling were used to determine layer temperatures and depth.

CFAST predicts the HGL temperature and height near experimental uncertainty for all three

tests, with relative differences ranging from 10 % to 15 %, depending on the test. Relative differences are shown in figure 6.1.

NIST/NRC Test Series

The NIST/NRC series consisted of 15 liquid spray fire tests with different heat release rates, pan

locations, and ventilation conditions. Gas temperatures were measured using seven floor-to-ceiling

thermocouple arrays (or “trees”) distributed throughout the compartment. The average hot gas

layer temperature and height were calculated using thermocouple Trees 1, 2, 3, 5, 6 and 7. Tree 4

was not used because one of its thermocouples malfunctioned during most of the experiments.

A few observations about the simulations:

• In the closed-door tests, the HGL layer descended all the way to the floor. However, the

reduction method used on the measured temperatures (see reference [77]) does not account

for the formation of a single layer and, therefore, does not indicate that the layer dropped all

the way to the floor, rather just to the position of the lowest temperature measurement point.

This is not a flaw in the measurements, but rather that the data reduction method only applies

to tests where two distinct layers are present, i.e., in the open door tests.

• The HGL reduction method produces spurious results in the first few minutes of each test

because no clear layer has yet formed.

CFAST predicts the HGL temperature to within experimental uncertainty for all of the closeddoor tests except Test 17. Test 17 was a rapidly growing toluene pool fire, which was stopped for

safety reasons after 273 seconds. CFAST predicts an initial temperature rise starting somewhat

earlier and peaking somewhat higher than the experimental values, but curve shapes match in all

tests. Relative difference for the open-door tests is somewhat higher, ranging from 13 % for Test

5 to 26 % for Test 18. CFAST predicts HGL height to within experimental uncertainty for the

open-door tests.

FM/SNL Test Series

Tests 4, 5, and 21 from the FM/SNL test series are selected for comparison. The hot gas layer

temperature and height are calculated using the standard method. The thermocouple arrays that

are referred to as Sectors 1, 2 and 3 are averaged (with an equal weighting for each) for Tests 4 and

5. For Test 21, only Sectors 1 and 3 are used, as Sector 2 falls within the smoke plume.

Note the following:

• The experimental HGL heights are somewhat noisy because of the effect of ventilation ducts

in the upper layer. The corresponding predicted HGL heights are consistently lower than

experimental measurements, typically approaching floor level by the end of the test. This

is likely a combination of the calculation technique for the experimental measurements and

rules for flow from mechanical vents in the CFAST model.

57
• The ventilation was turned off after 9 minutes in Test 5, the effect of which was a slight

increase in the measured HGL temperature.

CFAST predicts the HGL temperature to within experimental uncertainty for Tests 4 and 5.

For Test 21, there is a 33 % over-prediction. This is likely because of the configuration of the fire

in the test, with the fire inside a cabinet in the fire compartment. This complex geometry leads to

an interaction between the fire and the confining cabinet that a zone model cannot simulate.

iBMB Compartment Tests

CFAST predicts the HGL temperature and height to within experimental uncertainty for the pool

fire test (Test 1), but there is some discrepancy in the shapes of the curves. It is not clear whether

this is related to the measurement or the model.

CFAST predicts the HGL temperature to within experimental uncertainty for the cable fire

test (Test 4), although again there is a noticeable difference in the overall shape of the temperature

curves. HGL height is under-predicted by 20 %. This is likely because of the complicated geometry

within the compartment that includes a partial height wall that affects both plume entrainment and

radiative heat transfer from the fire to surroundings.

NBS Multi-Room Test Series

This series of experiments consists of two relatively small rooms connected by a long corridor. The

fire is located in one of the rooms. Eight vertical arrays of thermocouples are positioned throughout

the test space: one in the burn room, one near the door of the burn room, three in the corridor, one

in the exit to the outside at the far end of the corridor, one near the door of the other or “target”

room, and one inside the target room. Four of the eight arrays have been selected for comparison

with model prediction: the array in the burn room (BR), the array in the middle of the corridor (5.5

m from the BR), the array at the far end of the corridor (11.6 m from the BR), and the array in the

target room (TR). In Tests 100A and 100O, the target room is closed, in which case the array in

the exit (EXI) doorway is used. The test director reduced the layer information individually for the

eight thermocouple arrays using an alternative method. These results are included in the original

data sets. However, for the current validation study, the selected TC trees were reduced using the

method common to all the experiments considered.

CFAST predicts the HGL temperature and depth to within experimental uncertainty for many of

the measurement locations in the three tests considered, averaging 13 %1for the HGL temperature

and 15 % for the HGL depth. The discrepancies in various locations appear to be attributable

to experimental, rather than model, error. In particular, the calculation of HGL temperature and

height are quite sensitive to the measured temperature profile, which in these tests was determined

with bare-bead thermocouples that are subject to quite high uncertainties. Wide spacing of the

thermocouples also leads to higher uncertainty in HGL height.

Calculations of HGL temperature and depth in rooms remote from the fire tend to higher relative differences than those closer to the fire, ranging from -48 % to 29 %, but the average relative

1For average relative differences reported in this paper, the sign of the difference is ignored so that two values

with opposing signs do not cancel and make the average comparison appear closer than individual magnitudes would

indicate.

58
difference is 13 % for HGL temperature and 19 % for HGL depth. This is likely a combination of

the simplified single representative layer temperature inherent in zone models (temperature in the

long corridor of this test series varied from one end of the compartment to the other) and the calculation of flow though doorways based on a correlation based on the pressure difference between

the connected compartments.

FM Four Room Including Corridor Test Series

This series of experiments has a burn room connected to a long corridor with two smaller compartments at the far end of the corridor. Six vertical arrays of thermocouples (one in most compartments

and three in the corridor) were used to estimate layer temperature and depth. In general, CFAST

over predicts layer temperature and depth closer to the fire with a general trend towards under prediction at locations more remote from the fire; at times within experimental uncertainty but with

significant over prediction at other locations. Relative differences ranged from -20 % to 50 % for

HGL temperature (averaging within 22 %) and from -31 % to 32 % for HGL depth (averaging

within 19 %).

NIST Seven-story Hotel Tests

These tests were conducted in a seven story hotel with multiple rooms on each floor and a stairwell

connecting all floors. Layer temperatures are available for comparison directly from the data.

Relative differences comparing model and experiment are within experimental uncertainty except

on the seventh floor. While the relative difference for this location was quite large (292 %, this

represents a 2 ◦C over prediction by the model.

6.2 Summary

Following is a summary of the accuracy assessment for the HGL predictions. The two-zone assumption inherent in CFAST, modeled as a series of ordinary differential equations that describe

mass and energy conservation of flows in a multiple-compartment structure typically provide appropriate prediction of gas layer temperature and layer height for the applications studied.

• The CFAST predictions of the HGL temperature and height are, with a few exceptions,

within or close to experimental uncertainty. On average, predicted HGL temperature is

within 16 % and HGL depth is within 15 % of experimental measurements. The CFAST predictions are typical of those found in other studies where the HGL temperature is typically

somewhat over-predicted and HGL height somewhat lower (HGL depth somewhat thicker)

than experimental measurements. These differences are likely attributable to simplifications

in the model dealing with mixing between the layers, entrainment in the fire plume, and flow

through vents.

• Calculation of HGL temperature and height has higher uncertainty in rooms remote from

the fire compared to those in the fire compartment. Most likely, this is due to a combination

of the simplified vent flow predictions (based on idealized Bernoulli flow) and the assumption of constant compartment surface thermal properties that are assumed independent of

temperature.

59
60
Chapter 7

Flame Height, Plume Temperature and

Ceiling Jets

7.1 Flame Height

Flame height is recorded by visual observations, photographs, or video footage. Videos from the

NIST/NRC test series and photographs from the VTT Large Hall Test Series are available. It

is difficult to precisely measure the flame height, but the photos and videos allow one to make

estimates accurate to within a pan diameter.

VTT Large Hall Test Series

The height of the visible flame in the photographs has been estimated to be between 2.4 and 3 pan

diameters (3.8 m to 4.8 m). From the CFAST calculations, the estimated flame height is 4.3 m.

NIST/NRC Test Series

CFAST estimates the peak flame height to be 2.8 m, consistent with the roughly 3 m flame height

observed through the doorway during the test. The test series was not designed to record accurate

measurements of flame height.

7.2 Plume Temperature

CFAST includes a plume entrainment algorithm based on the work of McCaffrey that models the

transport of combustion products released by the fire with air in the fire compartment and movements of these gases into the upper layer in the compartment. Plume temperature is not directly

calculated nor reported from this algorithm. For this reason, comparisons of experimentally measured plume temperatures with CFAST calculations are not appropriate and will not be included in

this report.

61
7.3 Ceiling Jets

CFAST includes an algorithm to account for the presence of the higher gas temperatures near

the ceiling surfaces in compartments involved in a fire. In the model, this increased temperature

has the effect of increasing the convective heat transfer to ceiling surfaces. The temperature and

velocity of the ceiling jet are available from the model by placing a heat detector at the specified

location. The ceiling jet algorithm is based on the model by Cooper [78], with details described in

the CFAST Technical Reference Guide [2]. The algorithm predicts gas temperature and velocity

under a flat, unconstrained ceiling above a fire source. Only two of the six test series (NIST/NRC

and FM/SNL) involved relatively large flat ceilings.

Figure 7.1 shows a comparison of predicted and measured values for ceiling jet temperature.

Appendix A provides individual graphs of model and experimental values. Following is a summary

of the accuracy assessment for the ceiling jet predictions in the two test series:

NIST/NRC Test Series

The thermocouple nearest the ceiling in Tree 7, located towards the back of the compartment,

has been chosen as a surrogate for the ceiling jet temperature. This location was well removed

from the fire plume so that plume effects would not be evident, but closer to the wall surfaces so

that the assumption of an unconfined ceiling inherent in the typical ceiling jet correlations that

wall effects may impact the comparison. Still, CFAST predicts ceiling jet temperature well within

experimental uncertainty for all of the tests in the series, with an average relative difference of 5 %.

For these tests, the fire source was sufficiently large (relative to the compartment size) such that a

well-defined ceiling jet was evident in temperature measurements near ceiling level.

FM/SNL Test Series

With fire sizes comparable to the smaller fire sizes used in the tests in NIST/NRC test series

and compartment volumes significantly larger, measured temperature rise near the ceiling in the

FM/SNL tests was below 100 ◦C in all three tests. Hot gas layer temperatures for these tests

were below 70 ◦C . CFAST consistently predicts higher ceiling jet temperatures in the FM/SNL

tests compared to experimental measurements. With a larger compartment relative to the fire size,

the ceiling jet for the FM/SNL tests is not nearly as well-developed as those in the NIST/NRC

tests. The difference between the experimental ceiling jet temperature and HGL temperature for

the FM/SNL tests is less than half that observed in the NIST/NRC tests. While the over-prediction

of ceiling jet temperature could be considered conservative for some applications, for scenarios

involving sprinkler or heat detector activation, the increased temperature in the ceiling jet would

lead to shorter estimates of activation times for the simulated sprinkler or heat detector.

7.4 Summary

Based on the model physics and comparisons of model predictions with experimental measurements, CFAST provides appropriate calculations of ceiling jet temperature for the following reasons:

62
Figure 7.1: Comparison of Measured and Predicted Ceiling Jet Temperature.

63
• For tests with a well-defined ceiling jet layer beneath flat ceilings, CFAST predicts ceiling

jet temperatures well-within experimental uncertainty.

• For tests with a less well-defined ceiling jet layer, CFAST over-predicts the ceiling jet temperature. For the tests studies, over-predictions were noted when the HGL temperature was

below 70 ◦C.

64
Chapter 8

Gas Species and Smoke

CFAST simulates a fire as a mass of fuel that burns at a prescribed pyrolysis rate and releases both

energy and combustion products. CFAST calculates species production based on user-defined

production yields, and both the pyrolysis rate and the resulting energy and species generation

may be limited by the oxygen available for combustion. When sufficient oxygen is available for

combustion, the heat release rate for a constrained fire is the same as for an unconstrained fire.

Mass and species concentrations, assumed to be homogeneous throughout each layer, are tracked

by the model as gases flow through openings in a structure to other compartments in the structure

or to the outdoors.

The fire chemistry scheme in CFAST is essentially a species balance from user-prescribed

species yields and the oxygen available for combustion. Once generated, it is a matter of bookkeeping to track the mass of species throughout the various control volumes in a simulated building. It does, however, provide a check of the flow algorithms within the model. Since the major

species (CO and CO2) are generated only by the fire, the relative accuracy of the predicted values

throughout multiple rooms of a structure should be comparable.

8.1 Oxygen and CO2

Gas sampling data are available from a number of the experimental tests. Figure 8.1 shows a

comparison of predicted and measured values for oxygen and carbon dioxide concentrations, along

with a summary of the relative difference for the tests.

CFAST predicts the upper-layer concentrations of oxygen and carbon dioxide within an average of 20 % of experimental values. Details for individual test series are discussed below.

NBS Single Room Tests with Furniture

For the single-room tests with furniture, the predicted concentrations are lower than those measured

experimentally (with relative differences of 23 % for oxygen and 62 % for carbon dioxide). This

is probably due to the treatment of oxygen limited burning. In CFAST, the burning rate simply

decreases as the oxygen level decreases. A user prescribed lower limit determines the point below

which burning will not take place. This parameter could be finessed to provide better agreement

with the experiment. For the present comparisons, it was always left at the default value. Since this

65
Figure 8.1: Comparison of Measured and Predicted Oxygen Concentration and Carbon Dioxide

Concentration.

66
parameter impacts the overall combustion chemistry in CFAST and the generation of all species,

it would impact both oxygen and carbon dioxide.

In addition, species concentrations measured for large fires in small spaces can show considerable spatial variation within the upper layer of the fire compartment [79]. For such under-ventliated

fires, the representation of the species concentration in a hot gas layer by a single representative

average value may not be valid.

NIST/NRC Tests

For the closed-door tests 4 and 10 and open-door Tests 9 and 14, the magnitude of relative difference is higher, under-predicting by 22 % to 25 %. Tests 4, 10, and 16 were closed-door tests

with the mechanical ventilation system on. The higher relative differences for these tests are likely

because of a non-uniform gas layer in the experiments with higher oxygen concentration near

the mechanical ventilation inlet and lower concentrations remote from the inlet. In CFAST, the

flow from the mechanical ventilation system is assumed to completely mix with the gases in the

appropriate gas layer of a compartment. CFAST consistently under-predicts the drop in oxygen

concentration, with Tests 9 and 14 showing a higher relative uncertainty than other closed-door

tests. The cause of a higher-than-average difference is not clear.

iBMB Cable Fire Test

CFAST under predicts oxygen and carbon dioxide concentrations by 15 % and 9 %, respectively.

FM Four Room Including Corridor Test Series

For these four compartment tests, the end of test values of the gas concentrations agree far better

than the peak values. With the underlying assumption of all zone fire models of a uniform concentration of gas species throughout a control volume, it is assumed than the point measurement is

the bulk concentration of the entire upper layer. In reality, some vertical distribution not unlike the

temperature profile exists for the gas concentration as well.

Since this measurement point is near the lower edge of the upper layer for a significant time,

it should underestimate the bulk concentration until the layer is large in volume and well mixed.

Still, the relative differences for these tests are larger than the NIST/NRC tests, averaging 33 % for

oxygen and 17 % for carbon dioxide.

NIST Seven-story Hotel Tests

For the multiple-story building test, predicted values for CO2, CO, and O2 are lower than measured

experimentally. Both the lower burning rate limit as well as leakage in the 100 year- old structure

probably contributed to the differences between the experiments and model. In addition, values for

species yields were simply literature values since no test data were available.

67
8.2 NIST/NRC Test Series, Smoke

CFAST treats smoke like all other combustion products, with an overall mass balance dependent

on interrelated user-specified species yields for major combustion species. To model smoke movement, the user prescribes the smoke yield relative to the yield of carbon monoxide. A simple

combustion chemistry scheme in the model then determines the smoke particulate concentration

in the form of an optical density. Figure 8.2 shows a comparison of predicted and measured values

for smoke concentration along with a summary of the relative difference for the tests.

Only the NIST/NRC test series has been used to assess predictions of smoke concentration.

For these tests, the smoke yield was specified as one of the test parameters. There are two obvious

trends in the results. First, the predicted concentrations are within or near experimental uncertainties in the open-door tests. Second, the predicted concentrations are roughly three to five times

the measured concentrations in the closed-door tests. The experimental uncertainty for these measurements has been estimated to be 33 %. The closed-door tests cannot be explained from the

experimental uncertainty.

The difference between model and experiment is far more pronounced in the closed-door tests.

Given that the oxygen and carbon dioxide predictions are no worse (and indeed even better) in

the closed-door tests, there is reason to believe either that the smoke is not transported with the

other exhaust gases or the specified smoke yield, developed from free-burning experiments, is not

appropriate for the closed-door tests. These qualitative differences between the open- and closeddoor tests are consistent with the FDS predictions (see reference [80]).

8.3 Summary

Based on the model physics and comparisons of model predictions with experimental measurements, CFAST calculations of oxygen and carbon dioxide concentration are seen as appropriate

with the following comments:

• CFAST uses a simple user-specified combustion chemistry scheme based on a prescribed

pyrolysis rate and species yields that is appropriate for the applications studied.

• CFAST predicts the major gas species close to within 20 % of experimental measurements.

• For large fires in small compartments, local species concentration may vary considerably

from a bulk average value. Thus higher uncertainty can be expected for predictions of species

concentrations in these scenarios.

Use of CFAST calculations of smoke concentration require additional care for the following

reasons:

• CFAST is capable of transporting smoke throughout a compartment, assuming that the production rate is known and its transport properties are comparable to gaseous exhaust products.

68
Figure 8.2: Comparison of Measured and Predicted Smoke Concentration.

69
• CFAST typically over-predicts the smoke concentration in all of the NIST/NRC tests, with

the exception of Test 17. Predicted concentrations for open-door tests are within experimental uncertainties, but those for closed-door tests are far higher. No firm conclusions can

be drawn from this single data set. The measurements in the closed-door experiments are

inconsistent with basic conservation of mass arguments, or there is a fundamental change in

the combustion process as the fire becomes oxygen-starved.

70
Chapter 9

Pressure

Comparisons between measurement and prediction of compartment pressure for the NIST/NRC

test series and two of the NBS furniture tests are shown in of Appendix A. Figure 9.1 shows a

comparison of predicted and measured values for compartment pressure, along with a summary of

the relative difference for the tests.

For those tests in which the door to the compartment is open, the magnitude of the pressures

are only a few Pascals; however, when the door is closed, the over-pressures are several hundred

Pascals. For both the open- and closed-door tests, CFAST predicts the pressure to within experimental uncertainty with exceptions. The most notable exception is Test 16, which involved a large

(2.3 MW) fire with the door closed and the ventilation on. By contrast, Test 10 involved a 1.2 MW

fire with comparable geometry and ventilation. There is considerable uncertainty in the magnitude

of both the supply and return mass flow rates for Test 16. Compared to Test 16, Test 10 involves

a greater measured supply velocity and a lesser measured exhaust velocity. This is probably the

result of the higher pressure caused by the larger fire in Test 16. CFAST does not adjust the ventilation rate based on the compartment pressure until a specified cutoff pressure is reached. This is

also the most likely explanation for the over-prediction of compartment pressure in Test 16.

In general, prediction of pressure in CFAST in closed compartments is critically dependent

on correct specification of the leakage from the compartment. Compartments are rarely entirely

sealed, and small changes in the leakage area can produce significant changes in the predicted

over-pressure.

By comparison, the large relative differences for the two NBS compartment tests with furniture

and wall-burning are qualitatively difference than the NIST/NRC outlier. For these two tests, the

difference between model and experiment are on the order of 2 Pa rather than the more than 100 Pa

of the NIST/NRC test. Qualitatively, the comparison between model and experiment for the NBS

tests show similar curve shapes but with a notable single spike in the experimental measurements

which particularly effects the comparison of peak values.

Based on the model physics and comparisons of model predictions with experimental measurements, CFAST calculations of pressure are seen as appropriate for the tests considered with

the following reasons:

• With exceptions, CFAST predicts compartment pressures within experimental uncertainty.

• Prediction of compartment pressure for closed-door tests is critically dependent on correct

specification of the leakage from the compartment.

71
Figure 9.1: Comparison of Measured and Predicted Compartment Pressure.

72
Chapter 10

Heat Flux and Surface Temperature

10.1 NIST/NRC Test Series, Cables

Target temperature and heat flux data are available from the NIST/NRC test series. In the NIST/NRC

tests, the targets are different types of cables in various configurations: horizontal, vertical, in trays,

or free-hanging. Figure 10.1 shows a comparison of predicted and measured values for radiation,

total heat flux, and target temperature, along with a summary of the relative difference for the tests.

Appendix A provides nearly 200 comparisons of heat flux and surface temperature on four

different cables. The following trends are notable comparing CFAST predictions to experimental

measurements:

• Overall, the comparisons of target flux and temperature show larger relative differences than

other quantities. This is to be expected since the target flux and temperature are inherently

local quantities.

• The difference between predicted and measured cable surface temperatures is often within

experimental uncertainty, with exceptions most often in the values for the vertically-oriented

Cable G. Target surface temperature predictions average within 18 % of experimental values.

Accurate prediction of the surface temperature of the cable should indicate that the flux to

the target (a combination of radiation from the fire, surrounding surfaces, and the gas layers,

along with convection from the surrounding gas) should be correspondingly accurate. For

the NIST/NRC tests, the cable surface predictions show lower relative difference overall

compared to the total heat flux and (particularly) the radiative heat flux.

• Total heat flux to targets is typically predicted to within an average difference of 29 % and

often under-predicted. Predictions for Cables D (horizontal) and G (vertical) are notable

exceptions, with higher uncertainties.

• Radiative heat flux to targets is typically over-predicted compared to experimental measurements, with higher values for closed-door tests. For the closed-door tests, this may be a

function of the over-prediction of the smoke concentration, which leads to the radiation contribution from the hot gas layer being a larger fraction of the total heat flux compared to the

experimental values.

73
Figure 10.1: Comparisons of Measured and Predicted Heat Flux to Targets and Target Temperature

74
• For many of the experiments, the convective heat flux component, taken to be the difference

between the total heat flux and the radiative heat flux is seen to be higher than the values

typically measured in fire experiments.

10.2 NIST/NRC Test Series, Compartment Walls, Floor and

Ceiling

Thirty-six heat flux gauges were positioned at various locations on all four walls of the compartment, plus the ceiling and floor. Comparisons between measured and predicted heat fluxes and

surface temperatures are shown on the following pages for a selected number of locations. Over

half of the measurement points are in roughly the same relative location to the fire and hence the

measurements and predictions are similar. For this reason, data for the east and north walls are

shown because the data from the south and west walls are comparable. Data from the south wall

is used in cases where the corresponding instrument on the north wall failed, or in cases where the

fire is positioned close to the south wall. For each test, eight locations are used for comparison,

two on the long (mainly north) wall, two on the short (east) wall, two on the floor, and two on the

ceiling. Of the two locations for each panel, one is considered in the far-field, relatively remote

from the fire; one is in the near-field, relatively close to the fire. How close or far varies from test to

test, depending on the availability of working flux gauges. The two short wall locations are equally

remote from the fire; thus, one location is in the lower layer, one in the upper.

Figure 10.1 shows a comparison of predicted and measured values for radiation, total heat flux,

and target temperature, along with a summary of the relative difference for the tests.

CFAST predicts the heat flux and surface temperature of the compartment walls to within

31 % and 46 %, respectively. Typically, CFAST over-predicts the far-field fluxes and temperatures

and under-predicts the near-field measurements. This is understandable, given that any two-zone

model predicts an average representative value of gas temperature in the upper and lower regions

of a compartment. Thus, the values predicted by CFAST should be an average of values near the

fire and those farther away.

However, differences for the ceiling and (particularly) floor fluxes and temperatures are higher,

with a more pronounced difference between the near-field and far-field comparisons. In addition

to the limitations of the two-zone assumption, calculations of the flux to ceiling and floor surfaces

are further confounded by the simple point-source calculation of radiation exchange in CFAST for

the fire source. In CFAST, the fire is assumed to be a point source of energy located at the base

of the fire rather than a three-dimensional flame surface radiating to surroundings. With the fire

typically at the floor surface, this makes the calculation of flux to the floor surface inherently less

accurate than for other surfaces.

10.3 Summary

Use of CFAST for heat flux and temperature requires caution for the following reasons:

• Prediction of heat flux to targets and target surface temperature is largely dependent on local

conditions surrounding the target. Like any two-zone model, CFAST predicts an average

75
Figure 10.2: Comparisons of Measured and Predicted Heat Flux to Compartment Surfaces and

Surface Temperature

76
representative value of gas temperature in the upper and lower regions of a compartment.

In addition, CFAST does not directly predict plume temperature or its effects on targets that

may be within a fire plume. Thus, CFAST can be expected to under-predict values near a

fire source, and over-predict values for targets remote from a fire.

• Cable target surface temperature predictions are often within experimental uncertainty, with

exceptions, particularly for Cables F and G.

• Total heat flux to targets is typically predicted to within about 30 %, and often underpredicted.

• Radiative heat flux to targets is typically over-predicted compared to experimental measurements, with higher relative difference values for closed-door tests.

• CFAST is capable of predicting the surface temperature of a wall, assuming that its composition is fairly uniform and its thermal properties are well-characterized. Predictions are

typically within 10 % to 30 %. Generally, CFAST over-predicts the far-field fluxes and temperatures, and under-predicts the near-field measurements. This is consistent with the single

representative layer temperature assumed by zone fire models.

• CFAST predictions of floor heat flux and temperature are particularly problematic because of

the simple point-source calculation of radiative exchange between the fire and compartment

surfaces.

77
78
Chapter 11

Summary and Conclusions

How to best quantify the comparisons between model predictions and experiments is not obvious.

The necessary and perceived level of agreement for any variable is dependent upon both the typical

use of the variable in a given simulation, the nature of the experiment, and the context of the

comparison in relation to other comparisons being made. For instance, the user may be interested

in the time it takes to reach a certain temperature in the room, but have little or no interest in peak

temperature for experiments that quickly reach a steady-state value. Insufficient experimental data

and understanding of how to compare the numerous variables in a complex fire model prevent a

complete validation of the model.

A true validation of a model would involve proper statistical treatment of all the inputs and

outputs of the model with appropriate experimental data to allow comparisons over the full range of

the model. Thus, the comparisons of the differences between model predictions and experimental

data discussed here are intentionally simple and vary from test to test and from variable to variable

due to the changing nature of the tests and typical use of different variables.

Table 11.1 summarizes the comparisons in this report.

For four of the quantities, the physics of the model is appropriate to represent the experimental conditions, and the calculated relative differences comparing the model and the experimental

values are consistent with the combined experimental and input uncertainty. A few notes on the

comparisons are appropriate:

• The CFAST predictions of the HGL temperature and height are, with a few exceptions,

within or close to experimental uncertainty. The CFAST predictions are typical of those

found in other studies where the HGL temperature is typically somewhat over-predicted and

HGL height somewhat lower (HGL depth somewhat thicker) than experimental measurements. Still, predictions are mostly within 10 % to 20 % of experimental measurements.

Calculation of HGL temperature and height has higher uncertainty in rooms remote from the

fire (compared to those in the fire compartment).

• For most of the comparisons, CFAST predicts ceiling jet temperature well within experimental uncertainty. For cases where the HGL temperature is below 70 ◦C , significant and

consistent over-prediction was observed.

• CFAST predicts the flame height consistent with visual observations of flame height for the

experiments. This is not surprising, given that CFAST simply uses a well-characterized

79
Table 11.1: Summary of Model Comparisons

Quantity Average Median Within 90th

Differencea Differenceb Experimental Percentiled

Uncertaintyc

(%) (%) (%) (%)

HGL Temperature 6 14 52 30

HGL Depth 3 15 40 28

Ceiling Jet Temperature 16 5 70 61

Oxygen Concentration -6 18 12 32

Carbon Dioxide Concentration -16 16 21 52

Smoke Obscuratione 272/22 227/18 0/82 499/40

Pressure 43 13 77 206f

Target Flux (Total) -23 27 42 51

Target Temperature 0 18 38 34

Surface Flux (Total) 5 25 40 61

Surface Temperature 24 35 17 76

a - average difference includes both the sign and magnitude of the relative differences in order to

show any general trend to over- or under-prediction.

b - median difference is based only on the magnitude of the relative differences and ignores the

sign of the relative differences so that values with opposing signs do not cancel and make the

comparison appear closer than individual magnitudes would indicate.

c - the percentage of model predictions that are within experimental uncertainty.

d - 90 % of the model predictions are within the stated percentage of experimental values. For

reference, a difference of 100 % is a factor of 2 larger or smaller than experimental values.

e - the first number is for the closed door NIST/NRC tests and the second number if for the open

door NIST/NRC tests.

f - high magnitude of the 90th percentile value driven in large part by two tests where underprediction was approximately 2 Pa.

80
experimental correlation to calculate flame height.

• Gas concentrations are typically under-predicted by CFAST, with an average difference of

-6 % for oxygen concentration and -16 % for carbon dioxide concentration.

• Compartment pressure predicted by CFAST are within or close to experimental uncertainty

for most tests.

Three of the quantities were seen to require additional care when using the model to evaluate

the given quantity. This typically indicates limitations in the use of the model. A few notes on the

comparisons are appropriate:

• CFAST typically over-predicts smoke concentration. Predicted concentrations for open-door

tests are within experimental uncertainties, but those for closed-door tests are far higher.

• With exceptions, CFAST predicts cable surface temperatures within experimental uncertainties. Total heat flux to targets is typically predicted to within about 30 %, and often underpredicted. Radiative heat flux to targets is typically over-predicted compared to experimental

measurements, with higher relative difference values for closed-door tests. Care should be

taken in predicting localized conditions (such as target temperature and heat flux) because

of inherent limitations in all zone fire models.

• Predictions of compartment surface temperature and heat flux are typically within 10 %

to 30 %. Generally, CFAST over-predicts the far-field fluxes and temperatures and underpredicts the near-field measurements. This is consistent with the single representative layer

temperature assumed by zone fire models.

CFAST predictions in this validation study were consistent with numerous earlier studies,

which show that the use of the model is appropriate in a range of fire scenarios. The CFAST

model has been subjected to extensive evaluation studies by NIST and others. Although differences between the model and the experiments were evident in these studies, most differences can

be explained by limitations of the model as well as of the experiments. Like all predictive models,

the best predictions come with a clear understanding of the limitations of the model and the inputs

provided to perform the calculations.

81
82
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Appendix A:

Calculation of Layer Height and the

Average Upper and Lower Layer

Temperatures

Fire protection engineers often need to estimate the location of the interface between the hot,

smoke-laden upper layer and the cooler lower layer in a burning compartment. Zone fire models

such as CFAST compute this quantity directly, along with the average temperature of the upper

and lower layers. In an experimental test or a computational fluid dynamics (CFD) model like FDS

[45], there are not two distinct zones, but rather a continuous profile of temperature. Nevertheless,

methods have been developed to estimate layer height and average temperatures from a continuous

vertical profile of temperature. One such method [76] is as follows: Consider a continuous function

T(z) defining temperature T as a function of height above the floor z, where z = 0 is the floor and

z = H is the ceiling. Define Tu as the upper layer temperature, Tl as the lower layer temperature,

and zint as the interface height. Compute the quantities:

(H −zint) Tu +zint Tl =

Z H

0

T(z) dz = I1 (1)

(H −zint)

1

Tu

+zint

1

Tl

=

Z H

0

1

T(z)

dz = I2 (2)

Solve for zint:

zint =

Tl(I1 I2 −H

2

)

I1 +I2 T

2

l −2Tl H

(3)

Let Tl be the temperature in the lowest mesh cell and, using Simpson’s Rule, perform the

numerical integration of I1 and I2. Tu is defined as the average upper layer temperature via

(H −zint) Tu =

Z H

zint

T(z) dz (4)

For experimental test data or CFD model output, the integral function of temperature as a

function of height can be estimated empirically from a number of discrete data points. Further

discussion of similar procedures can be found in Ref. [81].

89

 

91

Appendix B: 

Model / Experiment Comparison Graphs 

This appendix provides comparisons of CFAST predictions and experimental measurements 

for the six series of fire experiments under consideration. Each section contains an assessment of 

the model predictions for the following quantities: 

B.1 Hot Gas Layer Temperature and Height 

B.2 Ceiling Jet Temperature 

B.3 Plume Temperature 

B.4 Flame Height 

B.5 Oxygen and Carbon Dioxide Concentration 

B.6 Smoke Concentration 

B.7 Compartment Pressure 

B.8 Target Heat Flux and Surface Temperature 

B.9 Wall Heat Flux and Surface Temperature 
 

92

B.1 Hot Gas Layer Temperature and Height 

CFAST is a classic two-zone fire model. For a given fire scenario, the model subdivides 

a compartment into two control volumes (or zones), which include a relatively hot upper layer 

and a relatively cool lower layer. In addition, CFAST adds a zone for the fire plume. The lower 

layer is primarily ambient air. By contrast, the hot upper layer (which is also known as the hot 

gas layer) is where combustion products accumulate via the plume. 

Within a compartment, each zone has homogeneous properties. That is, the temperature and gas 

concentrations are assumed to be constant throughout the zone; the properties only change 

as a function of time. The CFAST model describes the conditions in each zone by solving 

equations for conservation of mass, species, and energy, along with the ideal gas law.
 

93

VTT LARGE HALL TESTS

The HGL temperature and depth were calculated from the averaged gas temperatures from three 

vertical thermocouple arrays using the standard reduction method. There were 10 thermocouples 

in each vertical array, spaced 2 m (6.6 ft) apart in the lower two-thirds of the hall, and 1 m (3.3 ft) 

apart near the ceiling. Figure A-1 presents a snapshot from one of the simulations. 

Specified Leakage

Heptane

Pan Fire

Figure A-1. Cut-Away View of the Simulation of VTT Large Hall Tests, Case 2 
 

94

Hot Gas Layer Temperature

ICFMP BE #2, Case 1

Time (min)

0 2 4 6 8 10

Temperature (C)

0

20

40

60

80

100

120

140

Exp Time vs T_upper 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #2, Case 1

Time (min)

0 2 4 6 8 10

Height (m)

0

5

10

15

Exp Time vs Height 

CFAST Time vs HGL Height 1 

Hot Gas Layer Temperature

ICFMP BE #2, Case 2

Time (min)

0 2 4 6 8 10

Temperature (C)

0

20

40

60

80

100

120

140

Exp Time vs Exp Upper Temp 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #2, Case 2

Time (min)

0 2 4 6 8 10

Height (m)

0

5

10

15

Exp Time vs Exp Height 

CFAST Time vs HGL Height 1 

Hot Gas Layer Temperature

ICFMP BE #2, Case 3

Time (min)

0 2 4 6 8 10

Temperature (C)

0

20

40

60

80

100

120

140

Exp Time vs T_upper 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #2, Case 3

Time (min)

0 2 4 6 8 10

Height (m)

0

5

10

15

Exp Time vs Height 

CFAST Time vs HGL Height 1 

Figure A-2. Hot Gas Layer (HGL) Temperature and Height, VTT Large Hall Tests 
 

95

NIST/NRC TESTS 

The NIST/NRC tests consist of 15 liquid spray fire tests with different heat release rate, pan 

locations, and ventilation conditions. The basic geometry is shown in Figure A-3. 

Gas temperatures were measured using seven floor-to-ceiling thermocouple arrays (or “trees”) 

distributed throughout the compartment. The average HGL temperature and height were 

calculated using thermocouple Trees 1, 2, 3, 5, 6 and 7. Tree 4 was not used because one of its 

thermocouples (4-9) malfunctioned during most of the experiments. 

Liquid spray fire

Doorway Cable target locations

and directions

Figure A-3. Snapshot of Simulation of NIST/NRC Tests, Test 3 

A few observations about the simulations: 

• In the closed-door tests, the HGL layer descended all the way to the floor. However, 

the reduction method, used on the measured temperatures, does not account for the formation 

of a single layer and, therefore, does not indicate that the layer dropped all the way to 

the floor. This is not a flaw in the measurements, but rather in the data reduction method. 

• The HGL reduction method produces spurious results in the first few minutes of each test 

because no clear layer has yet formed. 
 

96

Hot Gas Layer Temperature

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

Hot Gas Layer Temperature

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

Hot Gas Layer Temperature

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

Hot Gas Layer Temperature

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

Figure A-4. Hot Gas Layer (HGL) Temperature and Height, NIST/NRC Tests 
 

97

Hot Gas Layer Temperature

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

Hot Gas Layer Temperature

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

Hot Gas Layer Temperature

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

Hot Gas Layer Temperature

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

 Figure A-5. Hot Gas Layer (HGL) Temperature and Height, NIST/NRC Tests 
 

98

Hot Gas Layer Temperature

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

The following graphs are from open-door tests

Hot Gas Layer Temperature

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

Hot Gas Layer Temperature

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

Figure A-6. Hot Gas Layer (HGL) Temperature and Height, NIST/NRC Tests 
 

99

Hot Gas Layer Temperature

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

Hot Gas Layer Temperature

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

Hot Gas Layer Temperature

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

Hot Gas Layer Temperature

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tavg upper layer (C) 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

Exp Time vs Layer Height above floor (m) 

CFAST Time vs HGL Height 1 

Figure A-7. Hot Gas Layer (HGL) Temperature and Height, NIST/NRC Tests 
 

100

iBMB Pool Fire Tests 

The iBMB pool fire tests consisted of two experiments, of which one (Test 1) was chosen for 

validation. Compared to the other experiments, this fire was relatively large in a relatively small 

compartment. Thus, its HGL temperature was considerably higher than the other fire tests under 

study. As shown in Figure A-8, the compartment geometry is fairly simple, with a single large 

vent from the compartment. 

Kerosene

Pan Fire

Compartment

Vent

Figure A-8. Snapshot of the Simulation of iBMB Pool Fire Test 1 

The HGL temperature prediction, while matching the experiment in maximum value, has a 

noticeably different shape than the measured profile, both in the first 5 minutes and following 

extinction. The HGL height prediction is distinctly different in the first 10 minutes and differs 

by about 40% after that time. There appears to be an error in the reduction of the experimental 

data. 
 

101

Hot Gas Layer Temperature

ICFMP BE #4, Test 1

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

200

400

600

800

Exp Time vs T up 

CFAST Time vs HGL Temp 1 

Hot Gas Layer Height

ICFMP BE #4, Test 1

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

5

6

Exp Time vs Layer Height 

CFAST Time vs HGL Height 1 

Figure A-9. Hot Gas Layer (HGL) Temperature and Height, iBMB Pool Fire Test 1 
 

102

iBMB Cable Fire Tests 

The iBMB cable fire tests were performed in the same fire test facility as the iBMB pool fire 

tests. Figure A-10 displays the overall geometry of the compartment, as idealized by CFAST. 

Only one of the experiments from this test series was used in the evaluation, Test 4, and only the 

first 20 minutes of the test, during the “pre-heating” stage when only the ethanol pool fire was 

active. The burner was lit after that point, and the cables began to burn. 

Ethanol

Pan Fire

Gas Burner

Fire

Vertical Cable

Bundles

Figure A-10. Snapshot of the Simulation of iBMB Cable Fire Test 4 
 

103

Hot Gas Layer (HGL) Temperature

ICFMP BE #5, Test 4

Time (min)

0 5 10 15 20

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs T_up 

CFAST Time vs HGL Temp 1 

Hot Gas Layer (HGL) Height

ICFMP BE #5, Test 4

Time (min)

0 5 10 15 20

Height (m)

0

1

2

3

4

5

Exp Time vs Layer height 

CFAST Time vs HGL Height 1 

Figure A-11. Hot Gas Layer (HGL) Temperature and Height, iBMB Cable Fire Test 4 
 

104

FM/SNL Test Series 

Tests 4, 5, and 21 from the FM/SNL test series were selected for comparison. The HGL temperature 

and height were calculated using the standard method. The thermocouple arrays that are referred 

to as Sectors 1, 2, and 3 were averaged (with an equal weighting for each) for Tests 4 and 5. 

For Test 21, only Sectors 1 and 3 were used, as Sector 2 fell within the smoke plume. 

Controlled

gas fire

Ceiling exhaust vent

Mechanical ventilation

supply 1.2 m below ceiling

Figure A-12. Snapshot from Simulation of FM/SNL Test 5 

Note the following: 

• The experimental HGL heights are somewhat noisy because of the effect of ventilation ducts 

in the upper layer. The corresponding predicted HGL heights are consistently lower than 

experimental measurements, typically approaching floor level by the end of the test. This is 

likely a combination of the calculation technique for the experimental measurements and 

rules for flow from mechanical vents in the CFAST model. 

• The ventilation was turned off after 9 minutes in Test 5, the effect of which was a slight 

increase in the measured HGL temperature. 
 

105

HGL Temperature

FM/SNL, Test 4

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

20

40

60

80

100

CFAST Time vs HGL Temp 1 

Exp Time(79) vs Layer Temperature 

HGL Height

FM/SNL, Test 4

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

5

6

CFAST Time vs HGL Height 

Exp Time vs Layer Height 

HGL Temperature

FM/SNL, Test 5

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

20

40

60

80

100

CFAST Time vs HGL Temp 1 

Exp Time(15) vs T_upper 

HGL Height

FM/SNL, Test 5

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

5

6

CFAST Time vs HGL Height 1 

Exp Time(15) vs Height 

HGL Temperature

FM/SNL, Test 21

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

20

40

60

80

100

120

CFAST Time vs HGL Temp 1 

Exp Time(79) vs Layer Temperature 

HGL Height

FM/SNL, Test 21

Time (min)

0 5 10 15 20 25 30

Height (m)

0

1

2

3

4

5

6

CFAST Time vs HGL Height 1 

Exp Time(79) vs BURN RATE(80) 

Figure A-13. Hot Gas Layer (HGL) Temperature and Height, FM/SNL Series 
 

106

NBS Multi-Room Test Series 

This series of experiments consisted of two relatively small rooms connected by a long corridor. 

The fire was located in one of the rooms. Eight vertical arrays of thermocouples were positioned 

throughout the test space (one in the burn room, one near the door of the burn room, three in the 

corridor, one in the exit to the outside at the far end of the corridor, one near the door of the other 

or “target” room, and one inside the target room). Six of the eight arrays were selected for 

comparison with model prediction (the array in the burn room, three arrays in the corridor, the 

array at the far end of the corridor, and the array in the target room). In Tests 100A and 100O, 

the target room was closed, in which case, the array in the exit doorway was used. 

Burn room

110 kW gas

burner fire

Target room

Figure A-14. Snapshot from Simulation of NBS Multi-Room Test 100Z 
 

107

Room 1 HGL Temperature

NBS Multiroom, Test 100A

Time (min)

0 5 10 15 20

Temperature (C)

0

100

200

300

400

Exp TIME vs UP BR 

CFAST Time vs HGL Temp 1 

Room 1 HGL Height

NBS Multiroom, Test 100A

Time (min)

0 5 10 15 20

Height (m)

0.0

0.5

1.0

1.5

2.0

Exp TIME vs HGT BR 

CFAST Time vs HGL Height 1 

Tree 4 HGL Temperature

NBS Multiroom, Test 100A

Time (min)

0 5 10 15 20

Temperature (C)

0

20

40

60

80

100

120

140

160

Exp TIME vs UP 18 

CFAST Time vs HGL Temp 4 

Tree 4 HGL Height

NBS Multiroom, Test 100A

Time (min)

0 5 10 15 20

Height (m)

0.0

0.5

1.0

1.5

2.0

Exp TIME vs HGT 18 

CFAST Time vs HGL Height 4 

Tree 5 HGL Temperature

NBS Multiroom, Test 100A

Time (min)

0 5 10 15 20

Temperature (C)

0

20

40

60

80

100

120

140

160

Exp TIME vs UP 38 

CFAST Time vs HGL Temp 5 

Tree 5 HGL Height

NBS Multiroom, Test 100A

Time (min)

0 5 10 15 20

Height (m)

0.0

0.5

1.0

1.5

2.0

Exp TIME vs HGT 38 

CFAST Time vs HGL Height 5 

Tree 6 HGL Temperature

NBS Multiroom, Test 100A

Time (min)

0 5 10 15 20

Temperature (C)

0

20

40

60

80

100

120

140

160

Exp TIME vs UP EXI 

CFAST Time vs HGL Temp 6 

Tree 6 HGL Height

NBS Multiroom, Test 100A

Time (min)

0 5 10 15 20

Height (m)

0.0

0.5

1.0

1.5

2.0

Exp TIME vs HGTEXI 

CFAST Time vs HGL Height 6 

Figure A-15. Hot Gas Layer (HGL) Temperature and Height, NBS Multiroom, Test 100A 
 

108

Room 1 HGL Temperature

NBS Multiroom, Test 100O

Time (min)

0 5 10 15 20

Temperature (C)

0

100

200

300

400

Exp TIME vs UP BR 

CFAST Time vs HGL Temp 1 

Room 1 HGL Height

NBS Multiroom, Test 100O

Time (min)

0 5 10 15 20

Height (m)

0.0

0.5

1.0

1.5

2.0

Exp TIME vs HGT BR 

CFAST Time vs HGL Height 1 

Tree 4 HGL Temperature

NBS Multiroom, Test 100O

Time (min)

0 5 10 15 20

Temperature (C)

0

20

40

60

80

100

120

140

160

Exp TIME vs UP 18 

CFAST Time vs HGL Temp 4 

Tree 4 HGL Height

NBS Multiroom, Test 100O

Time (min)

0 5 10 15 20

Height (m)

0.0

0.5

1.0

1.5

2.0

Exp TIME vs HGT 18 

CFAST Time vs HGL Height 4 

Tree 5 HGL Temperature

NBS Multiroom, Test 100O

Time (min)

0 5 10 15 20

Temperature (C)

0

20

40

60

80

100

120

140

160

Exp TIME vs UP 38 

CFAST Time vs HGL Temp 5 

Tree 5 HGL Height

NBS Multiroom, Test 100O

Time (min)

0 5 10 15 20

Height (m)

0.0

0.5

1.0

1.5

2.0

Exp TIME vs HGT 38 

CFAST Time vs HGL Height 5 

Tree 6 HGL Temperature

NBS Multiroom, Test 100O

Time (min)

0 5 10 15 20

Temperature (C)

0

20

40

60

80

100

120

140

160

Exp TIME vs UP EXI 

CFAST Time vs HGL Temp 6 

Tree 6 HGL Height

NBS Multiroom, Test 100O

Time (min)

0 5 10 15 20

Height (m)

0.0

0.5

1.0

1.5

2.0

Exp TIME vs HGTEXI 

CFAST Time vs HGL Height 6 

Figure A-16. Hot Gas Layer (HGL) Temperature and Height, NBS Multiroom, Test 100O 
 

109

Room 1 HGL Temperature

NBS Multiroom, Test 100Z

Time (min)

0 5 10 15 20

Temperature (C)

0

100

200

300

400

Exp TIME vs UP BR 

CFAST Time vs HGL Temp 1 

Room 1 HGL Height

NBS Multiroom, Test 100Z

Time (min)

0 5 10 15 20

Height (m)

0.0

0.5

1.0

1.5

2.0

Exp TIME vs HGT BR 

CFAST Time vs HGL Height 1 

Tree 4 HGL Temperature

NBS Multiroom, Test 100Z

Time (min)

0 5 10 15 20

Temperature (C)

0

20

40

60

80

100

120

140

160

Exp TIME vs UP 18 

CFAST Time vs HGL Temp 4 

Tree 4 HGL Height

NBS Multiroom, Test 100Z

Time (min)

0 5 10 15 20

Height (m)

0.0

0.5

1.0

1.5

2.0

Exp TIME vs HGT 18 

CFAST Time vs HGL Height 4 

Tree 5 HGL Temperature

NBS Multiroom, Test 100Z

Time (min)

0 5 10 15 20

Temperature (C)

0

20

40

60

80

100

120

140

160

Exp TIME vs UP 38 

CFAST Time vs HGL Temp 5 

Tree 5 HGL Height

NBS Multiroom, Test 100Z

Time (min)

0 5 10 15 20

Height (m)

0.0

0.5

1.0

1.5

2.0

Exp TIME vs HGT 38 

CFAST Time vs HGL Height 5 

Tree 8 HGL Temperature

NBS Multiroom, Test 100Z

Time (min)

0 5 10 15 20

Temperature (C)

0

20

40

60

80

100

120

140

160

Exp TIME vs UP TR 

CFAST Time vs HGL Temp 8 

Tree 8 HGL Height

NBS Multiroom, Test 100Z

Time (min)

0 5 10 15 20

Height (m)

0.0

0.5

1.0

1.5

2.0

Exp TIME vs HGT TR 

CFAST Time vs HGL Height 8 

Figure A-17. Hot Gas Layer (HGL) Temperature and Height, NBS Multiroom, Test 100Z 
 

110

Table A-1. Relative Differences for Hot Gas Layer (HGL) Temperature and Height 

Exp CFAST Relative 

Difference Exp CFAST Relative 

Difference

(°C) (°C) (%) (m) (m) (%)

Case 1 55 62 14

Case 2 86 99 15

Case 3 83 91 10 13.9 14.9 8

Test 1 123 135 10

Test 7 117 133 13

Test 2 229 235 2

Test 8 218 234 8

Test 4 204 222 9

Test 10 198 221 12

Test 13 290 311 7

Test 16 268 290 8

Test 17 135 143 6

Test 3 207 243 17 2.9 2.8 -3

Test 9 204 241 18 2.9 2.8 -4

Test 5 175 198 13 3.0 2.7 -10

Test 14 208 242 16 2.9 2.8 -4

Test 15 211 242 15 2.9 2.8 -3

Test 18 193 243 26 2.9 -2.8 4

iBMB Test 1 700 602 -14 4.2 5.1 21

iBMB Test 4 151 172 14 4.3 3.4 -20

Test 4 59 69 16

Test 5 44 49 11

Test 21 66 88 33

Burn Room 244.1 290.8 19 2.0 1.4 -31

Corridor 55.9 87.4 56 2.0 2.3 14

Corridor 61.0 87.4 43 2.0 2.3 13

Corridor 76.4 87.4 14 1.9 2.3 17

Target Room 1 50.2 42.5 -15 2.0 2.4 21

Target Room 2 43.3 23.3 23 2.1 2.4 17

Burn Room 345.3 325.6 -6 1.7 2.3 32

Corridor 82.0 102.5 25 2.1 2.4 14

Corridor 90.9 102.5 13 2.1 2.4 16

Corridor 113.6 102.5 -10 2.0 2.4 19

Target Room 1 73.2 58.8 -20 2.1 2.4 16

Target Room 2 73.2 59.9 -18 2.1 2.4 15

Burn Room 259 237 -8 1.3 1.3 4

Corridor 18 86 88 2 1.2 1.2 1

Corridor 38 77 88 14 1.3 1.2 -8

Corridor Exit 74 88 19 1.2 1.2 0

Burn Room 312 336 8

Corridor 18 106 75 -30

Corridor 38 99 75 -25

Corridor Exit

Burn Room 286 240 -16 1.3 1.3 -1

Corridor 18 67 64 -5 1.2 1.5 29

Corridor 38 67 64 -5 1.2 1.5 25

Target Room 37 33 -9 1.4 2.1 -48

769.9 727.9 -5 2.1 2.0 -5

895.7 727.9 -19 2.2 2.0 -12

563.9 609.3 8 2.2 1.8 -19

875.9 609.3 -30 1.4 1.8 26

Test W1 Burn Room 777.0 589.4 -24 2.2 1.7 -23

Test W2 Burn Room 783.4 1193.1 52 2.3 1.8 -22

Burn Room 154.5 166.6 8

Corridor 424.0 387.8 -9

Floor 7 0.6 2.3 292

NIST 

Plaza

Test 7

FM 

SNL

MV100A

MV100O

NBS

FM 19

Hot Gas Layer Depth

VTTNIST / NRC

Series Test

Hot Gas Layer Temperature Rise

Measurement 

Position

Test F6 Burn Room

FM 21

FM NBS

Test F1 Burn Room

MV100Z
 

111

B.2 Ceiling Jet Temperature 

CFAST includes an algorithm to account for the presence of the higher gas temperatures near the 

ceiling surfaces in compartments involved in a fire. In the model, this increased temperature has 

the effect of increasing the convective heat transfer to ceiling surfaces. Temperature and 

velocity of the ceiling jet is available from the model by placing a heat detector at the specified 

location. The ceiling jet algorithm is based on the model by Cooper, with details described in the 

CFAST Technical Reference Guide. The algorithm predicts gas temperature and velocity under 

a flat, unconstrained ceiling above a fire source. Only two of the six test series (NIST/NRC 

Tests and FM/SNL) involved relatively large flat ceilings. 

NIST/NRC Test Series 

Ceiling Jet Temperature

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Ceiling Jet Temperature

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Ceiling Jet Temperature

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Ceiling Jet Temperature

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Ceiling Jet Temperature

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Ceiling Jet Temperature

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Figure A-18. Ceiling Jet Temperature, NIST/NRC Tests 
 

112

Ceiling Jet Temperature

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Ceiling Jet Temperature

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Ceiling Jet Temperature

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

The following graphs are from open-door tests

Ceiling Jet Temperature

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Ceiling Jet Temperature

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Figure A-19. Ceiling Jet Temperature, NIST/NRC Tests 
 

113

Ceiling Jet Temperature

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Ceiling Jet Temperature

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Ceiling Jet Temperature

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Ceiling Jet Temperature

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs Tree 7-10 

CFAST Time vs Ceiling Jet Temp 

Figure A-20. Ceiling Jet Temperature, NIST/NRC Tests 
 

114

FM / SNL Test Series 

Ceiling Jet Temperature

FM/SNL, Test 4

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

CFAST Time vs Ceiling Jet Temp #2 

CFAST Time vs Ceiling Jet Temp #1 

Exp Time(100) vs 1/(0.98 H) 

Exp Time(100) vs 11/(0.98 H) 

Ceiling Jet Temperature

FM/SNL, Test 5

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

CFAST Time vs Ceiling Jet Temp #2 

CFAST Time vs Ceiling Jet Temp #1 

Exp Time(15) vs 1/(0.98 H) 

Exp Time(15) vs 11/(0.98 H) 

Ceiling Jet Temperature

FM/SNL, Test 5

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

CFAST Time vs Ceiling Jet Temp 2 

CFAST Time vs Ceiling Jet Temp 1 

Exp Time(100) vs 1/(0.98 H) 

Exp Time(100) vs 11/(0.98 H) 

Figure A-21. Ceiling Jet Temperature, FM/SNL Tests 
 

115

Table A-2. Relative Differences for Ceiling Jet Temperature 

 Ceiling Jet Temperature Rise 

Series Test Measurement 

Position 

Exp CFAST Relative 

Difference 

(°C) (°C) (%) 

NIST / NRC 

Test 1 155 135 -13 

Test 7 139 133 -5 

Test 2 271 235 -13 

Test 8 247 233 -6 

Test 4 229 222 -3 

Test 10 218 221 2 

Test 13 330 311 -6 

Test 16 278 290 4 

Test 17 156 143 -8 

Test 3 241 243 1 

Test 9 235 241 3 

Test 5 208 198 -5 

Test 14 241 242 0 

Test 15 244 242 -1 

Test 18 235 243 3 

FM SNL 

Test 4 Temp 1 82 133 62 

Temp 2 66 102 56 

Test 5 Temp 1 70 101 44 

Temp 2 53 75 43 

Test 21 Temp 1 75 159 113 

Temp 2 77 124 61 

B.3 Plume Temperature 

CFAST includes a plume entrainment algorithm based on the work of McCaffrey that models the 

mixing of combustion products released by the fire with air in the fire compartment and 

movements of these gases into the upper layer in the compartment. Plume temperature is not 

directly calculated nor reported in a CFAST calculation. For this reason, comparisons of 

experimentally measured plume temperatures with CFAST calculations are not appropriate 

and are not included in this report. 
 

116

B.4 Flame Height 

Flame height is recorded by visual observations, photographs or video footage. Videos from the 

NIST/NRC test series and photographs from BE #2 are available. It is difficult to precisely 

measure the flame height, but the photos and videos allow one to make estimates accurate to 

within a pan diameter. 

VTT LARGE HALL TESTS 

Figure A-22 contains photographs of the actual fire. The height of the visible flame in the 

photographs has been estimated to be between 2.4 and 3 pan diameters (3.8 m to 4.8 m). From 

the CFAST calculations, the estimated flame height is 4.3 m (14.1 ft). 
 

117

Figure A-22. Photographs of Heptane Pan Fires, VTT Large Hall Tests, Case 2 

(Courtesy, Simo Hostikka, VTT Building and Transport, Espoo, Finland) 
 

118

NIST/NRC TESTS 

No measurements were made of the flame height during The NIST/NRC tests, but numerous 

photographs were taken through the doorway, which measured 2 m x 2 m (6.6 ft x 6.6 ft). 

During Test 3, the peak flame height was estimated to be 2.8 m (9.2 ft), roughly consistent with 

the view through the doorway in the figure below. 

Figure A-23. Photograph and Simulation of NIST/NRC Tests, Test 3, as seen through the 2 m x 2 m 

doorway (Courtesy of Francisco Joglar, SAIC) 
 

119

B.5 Oxygen Concentration 

CFAST simulates a fire as a mass of fuel that burns at a prescribed “pyrolysis” rate and releases 

both energy and combustion products. Species production is based on user-defined production 

yields and both the pyrolysis rate and the resulting energy and species generation may be limited 

by the oxygen available for combustion. Mass and species concentrations are tracked by the 

model as gases flow through openings in a structure to other compartments in the structure or to 

the outdoors. 

The following pages present comparisons of oxygen and carbon dioxide concentration 

predictions with measurement for The NIST/NRC tests and the iBMB cable fire tests. In The 

NIST/NRC tests, there were two oxygen measurements, one in the upper layer, one in the lower 

layer. There was only one carbon dioxide measurement in the upper layer. For iBMB cable fire 

test 4, a plot of upper-layer oxygen and carbon dioxide is included along with the results for The 

NIST/NRC tests. 

Not surprisingly, the accuracy of the gas species predictions is comparable to that of the HGL 

temperature. After all, CFAST uses the same basic algorithm for transport, regardless of 

whether it is the transport of heat or mass. CFAST predicts the upper-layer concentrations of 

oxygen and carbon dioxide within an average of 20 % of experimental values, tending to underpredict the drop in oxygen concentration and the carbon dioxide concentration. It worth noting 

that all of the gas species measurements are single point measurements that are compared to the 

homogeneous layer average value for the model predictions. 
 

120

O2 and CO2 Concentration

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

Figure A-24. Oxygen and Carbon Dioxide Concentration, NIST/NRC Tests 
 

121

O2 and CO2 Concentration

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Volume Fraction 0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #5, Test 4

Time (min)

0 5 10 15 20

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs GA 2-O2 

Exp Time vs GA 2-CO2 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

O2 and CO2 Concentration

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Volume Fraction

0.00

0.05

0.10

0.15

0.20

0.25

Exp Time vs O2-1 

Exp Time vs CO2-4 

CFAST Time vs O2 1 

CFAST Time vs CO2 1 

Figure A-25. Oxygen and Carbon Dioxide Concentration, NIST/NRC Tests (Note that the single test 

from the iBMB cable fire test is included at the upper right) 
 

122

Table A-3. Relative Differences for Oxygen and Carbon Dioxide Concentration 

Exp CFAST Relative 

Difference Exp CFAST Relative Difference

(molar 

fraction)

(molar 

fraction) (%) (molar fraction)

(molar 

fraction) (%)

Test 1 0.065 0.076 17 0.038 0.044 16

Test 7 0.064 0.073 14 0.038 0.043 12

Test 2 0.092 0.100 9 0.054 0.059 8

Test 8 0.096 0.098 2 0.058 0.057 -1

Test 4 0.079 0.060 -24 0.047 0.035 -26

Test 10 0.079 0.059 -25 0.047 0.035 -25

Test 13 0.101 0.110 10 0.060 0.064 7

Test 16 0.091 0.075 -18 0.055 0.044 -21

Test 17 0.033 0.031 -7 0.022 0.017 -23

Test 3 0.052 0.044 -15 0.031 0.027 -12

Test 9 0.054 0.042 -22 0.031 0.027 -14

Test 5 0.030 0.026 -14 0.017 0.016 -8

Test 14 0.055 0.042 -24 0.032 0.027 -16

Test 15 0.052 0.042 -19 0.031 0.027 -15

Test 18 0.051 0.044 -14 0.031 0.027 -11

iBMB Test 4 0.023 0.020 -15 0.013 0.012 -9

Burn Room 0.031 0.047 52 0.023 0.025 7

Corridor 0.037 0.031 -16 0.020 0.016 -20

Target Room 1 0.018 0.015 -18

Target Room 2 0.019 0.015 -23

Burn Room 0.060 0.085 42 0.033 0.044 33

Corridor 0.044 0.054 23 0.030 0.028 -7

Corridor 0.032 0.028 -13

Target Room 1 0.028 0.023 -16

Target Room 2 0.028 0.024 -16

0.209 0.139 -33 0.169 0.054 -68

0.195 0.139 -29 0.162 0.054 -67

0.140 0.101 -28 0.106 0.039 -63

0.099 0.101 2 0.081 0.039 -51

0.110 0.084 -24 0.040 0.029 -29

HGL Carbon Dioxide 

Concentration

NIST / NRC

Series Test

Test F1

NBS

FM19

FM21

FM NBS

NIST Plaza

Measurement 

Position

Test F6 Burn Room

Burn Room

HGL Oxygen Concentration 

Decrease

B.6 Smoke Concentration 

CFAST treats smoke like all other combustion products, with an overall mass balance dependent 

on interrelated user-specified species yields for major combustion species. To model smoke 

movement, the user prescribes the smoke yield relative to the yield of carbon monoxide. 

A simple combustion chemistry scheme in the model then determines the smoke particulate 

concentration in the form of an optical density. For The NIST/NRC tests, the smoke yield was 

specified as one of the test parameters. 
 

123

Figure A-26 and Figure A-27 contain comparisons of measured and predicted smoke concentration 

at one measuring station in the upper layer. There are two obvious trends in the figures. First, 

the predicted concentrations average 22% higher than the measured in the open-door tests, 

within experimental uncertainty with a single exception for Test 14. Second, the predicted 

concentrations are roughly three times the measured concentrations in the closed-door tests.
 

124

Smoke Concentration

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

50

100

150

200

250

300

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Smoke Concentration

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

50

100

150

200

250

300

350

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Smoke Concentration

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

100

200

300

400

500

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Smoke Concentration

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

100

200

300

400

500

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Smoke Concentration

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

50

100

150

200

250

300

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Smoke Concentration

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

50

100

150

200

250

300

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Smoke Concentration

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

100

200

300

400

500

600

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Smoke Concentration

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

50

100

150

200

250

300

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Figure A-26. Smoke Concentration, NIST/NRC Tests 
 

125

Smoke Concentration

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

500

1000

1500

2000

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

The following graphs are from open-door 

tests

Smoke Concentration

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

50

100

150

200

250

300

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Smoke Concentration

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

50

100

150

200

250

300

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Smoke Concentration

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

50

100

150

200

250

300

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Smoke Concentration

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

50

100

150

200

250

300

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Smoke Concentration

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

50

100

150

200

250

300

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Smoke Concentration

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Smoke Density (mg/m3

)

0

50

100

150

200

250

300

Exp Time vs Smoke Conc. 

CFAST Time vs OD 1 

Figure A-27. Smoke Concentration, NIST/NRC Tests 
 

126

Table A-4. Relative Differences for Smoke Concentration 

Exp CFAST Relative 

Difference

(mg/m3

) (mg/m3) (%)

Test 1 42 321 672

Test 7 55 307 457

Test 2 128 420 228

Test 8 100 411 313

Test 4 80 177 122

Test 10 71 177 150

Test 13 224 480 115

Test 16 139 204 47

Test 17 353 1590 350

Test 3 118 140 18

Test 9 117 139 19

Test 5 87 91 4

Test 14 91 139 53

Test 15 124 140 13

Test 18 110 140 27

Smoke Concentration

NIST / NRC

Series Test

B.7 Compartment Pressure 

Experimental measurements for room pressure are available only from the NIST/NRC Tests test 

series. The pressure within the compartment was measured at a single point, near the floor. In the 

simulations of the closed-door tests, the compartment is assumed to leak via a small vent near the 

ceiling with an area consistent with the measured leakage area. The location of the leak should 

not impact the results and was an arbitrary choice for consistency with simulations from a 

number of other models in the original NRC validation study [5]. 

Comparisons between measurement and prediction are shown in Figure A-28 and Figure A-29. 

For those tests in which the door to the compartment is open, the over-pressures are only a few 

Pascals, whereas when the door is closed, the over-pressures are several hundred Pascals. 

In general, the predicted pressures are of comparable magnitude to the measured pressures and, 

in most cases, differences can be explained using the reported uncertainties in the leakage area 

and the fact that the leakage area changed from test to test because of the thermal stress on the 

compartment walls. The one notable exception is Test 16. This experiment was performed with 

the door closed and the ventilation on, and there is considerable uncertainty in the magnitude of 

both the supply and return mass flow rates. 
 

127

Compartment Pressure

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-80

-60

-40

-20

0

20

40

60

80

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Compartment Pressure

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-60

-40

-20

0

20

40

60

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Compartment Pressure

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-600

-400

-200

0

200

400

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Compartment Pressure

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-500

-400

-300

-200

-100

0

100

200

300

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Compartment Pressure

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-600

-500

-400

-300

-200

-100

0

100

200

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Compartment Pressure

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-500

-400

-300

-200

-100

0

100

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Compartment Pressure

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-1000

-800

-600

-400

-200

0

200

400

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Compartment Pressure

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-1200

-1000

-800

-600

-400

-200

0

200

400

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Figure A-28. Compartment Pressure, NIST/NRC Tests 
 

128

Compartment Pressure

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Pressure (Pa) -300

-200

-100

0

100

200

300

Exp Time vs CompP 

CFAST Time vs Pressure 1 

The following graphs are from open-door 

tests

Compartment Pressure

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-3

-2

-1

0

1

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Compartment Pressure

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-3

-2

-1

0

1

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Compartment Pressure

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-3

-2

-1

0

1

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Compartment Pressure

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-3

-2

-1

0

1

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Compartment Pressure

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-3

-2

-1

0

1

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Compartment Pressure

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Pressure (Pa)

-3

-2

-1

0

1

Exp Time vs CompP 

CFAST Time vs Pressure 1 

Figure A-29. Compartment Pressure, NIST/NRC Tests 
 

129

Table A-5. Relative Differences for Compartment Pressure 

Exp CFAST Relative 

Difference

(Pa) (Pa) (%)

Test 1 58 42 -26

Test 7 46 29 -37

Test 2 290 266 -8

Test 8 189 214 13

Test 4 57 77 36

Test 10 49 46 -7

Test 13 232 336 45

Test 16 81 309 283

Test 17 195 137 -29

Test 3 -1.9 -2.1 10

Test 9 -2.0 -2.1 7

Test 5 -1.8 -2.0 8

Test 14 -2.1 -2.1 3

Test 15 -2.4 -2.2 -6

Test 18 -2.0 -2.1 7

Test W1 -1.8 -4.7 155

Test W2 -1.7 -6.5 282

Comparment Pressure Rise

NIST / NRC

Series Test

NBS
 

130

B.8 Target Temperature and Heat Flux 

Target temperature and heat flux data are available from NIST/NRC Tests, #4, and #5. In The 

NIST/NRC tests, the targets are various types of cables in various configurations — horizontal, 

vertical, in trays, or free-hanging. In the iBMB pool fire tests, the targets are three rectangular 

slabs of different materials instrumented with heat flux gauges and thermocouples. In the iBMB 

cable fire tests, the targets are again cables, in this case, bundled power and control cables in a 

vertical ladder. 

NIST/NRC TESTS 

For each of the four cable targets considered, measurements of the target surface temperature 

and total heat flux are compared for Control Cable B, Horizontal Cable Tray D, Power Cable F, 

and Vertical Cable Tray G. 

CFAST does not have a detailed model of the heat transfer within the bundled, cylindrical, 

non-homogenous cables. CFAST assumes all cable targets to be rectangular homogeneous slabs 

of thickness comparable to the diameter of the individual cables. Material properties for the targets 

are assumed to be those of the covering material for the respective cables. 
 

131

 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

2.5

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

 

Control Cable B Surface Temperature

ICFMP BE #3, Test 1

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Control Cable B Surface Temperature

ICFMP BE #3, Test 7

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Figure A-30. Thermal Environment near Cable B, NIST/NRC Tests, Tests 1 and 7 
 

132

 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

Control Cable B Surface Temperature

ICFMP BE #3, Test 2

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Control Cable B Surface Temperature

ICFMP BE #3, Test 8

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Figure A-31. Thermal Environment near Cable B, NIST/NRC Tests, Tests 2 and 8 
 

133

 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

Control Cable B Surface Temperature

ICFMP BE #3, Test 4

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Control Cable B Surface Temperature

ICFMP BE #3, Test 10

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Figure A-32. Thermal Environment near Cable B, NIST/NRC Tests, Tests 4 and 10 
 

134

 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

Control Cable B Surface Temperature

ICFMP BE #3, Test 13

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Control Cable B Surface Temperature

ICFMP BE #3, Test 16

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Figure A-33. Thermal Environment near Cable B, NIST/NRC Tests, Tests 13 and 16 
 

135

 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

Control Cable B Surface Temperature

ICFMP BE #3, Test 3

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Control Cable B Surface Temperature

ICFMP BE #3, Test 9

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Figure A-34. Thermal Environment near Cable B, NIST/NRC Tests, Tests 3 and 9 
 

136

 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

Control Cable B Surface Temperature

ICFMP BE #3, Test 5

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Control Cable B Surface Temperature

ICFMP BE #3, Test 14

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Figure A-35. Thermal Environment near Cable B, NIST/NRC Tests, Tests 5 and 14 
 

137

 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

20

40

60

80

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

Total Heat Flux to Control Cable B

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Cable Total Flux 4 

Exp Time vs Cable Rad Gauge 3 

CFAST Time vs Cable B Flux 

CFAST Time vs Cable B Rad 

Control Cable B Surface Temperature

ICFMP BE #3, Test 15

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Control Cable B Surface Temperature

ICFMP BE #3, Test 18

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs B-Ts-14 

CFAST Time vs Cable B Temp 

Figure A-36. Thermal Environment near Cable B, NIST/NRC Tests, Tests 15 and 18 
 

138

 

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 7 Gauge 8 inoperative

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

2.5

3.0

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 7 

Cable Tray D Surface Temperature

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Thermocouple inoperative

Cable Tray D Surface Temperature

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Figure A-37. Thermal Environment near Cable Tray D, NIST/NRC Tests, Tests 1 and 7 
 

139

 

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 1 

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 7 

Cable Tray D Surface Temperature

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Cable Tray D Surface Temperature

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Figure A-38. Thermal Environment near Cable Tray D, NIST/NRC Tests, Tests 2 and 8 
 

140

 

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 7 

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 7 

Cable Tray D Surface Temperature

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Cable Tray D Surface Temperature

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Figure A-39. Thermal Environment near Cable Tray D, NIST/NRC Tests, Tests 4 and 10 
 

141

 

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

12

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 7 

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

12

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 7 

Cable Tray D Surface Temperature

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Cable Tray D Surface Temperature

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Figure A-40. Thermal Environment near Cable Tray D, NIST/NRC Tests, Tests 13 and 16 
 

142

 

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 7 

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 7 

Cable Tray D Surface Temperature

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Cable Tray D Surface Temperature

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Figure A-41. Thermal Environment near Cable Tray D, NIST/NRC Tests, Tests 3 and 9 
 

143

 

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 7 

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 7 

Cable Tray D Surface Temperature

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Cable Tray D Surface Temperature

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Figure A-42. Thermal Environment near Cable Tray D, NIST/NRC Tests, Tests 5 and 14 
 

144

 

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

5

10

15

20

25

30

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 7 

Total Heat Flux to Cable Tray D

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs Cable D Flux 

CFAST Time vs Cable D Rad 

Exp Time vs Cable Total Flux 8 

Exp Time vs Cable Rad Gauge 7 

Cable Tray D Surface Temperature

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Cable Tray D Surface Temperature

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs D-Ts-12 

CFAST Time vs Cable D Temp 

Figure A-43. Thermal Environment near Cable Tray D, NIST/NRC Tests, Tests 15 and 18 
 

145

 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 10 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Power Cable F Surface Temperature

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs F-Ts-20 

CFAST Time vs Cable F Temp 

Power Cable F Surface Temperature

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs F-Ts-20 

CFAST Time vs Cable F Temp 

Figure A-44. Thermal Environment near Power Cable F, NIST/NRC Tests, Tests 1 and 7 
 

146

 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Power Cable F Surface Temperature

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs F-Ts-20 

CFAST Time vs Cable F Temp 

Power Cable F Surface Temperature

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs F-Ts-20 

CFAST Time vs Cable F Temp 

Figure A-45. Thermal Environment near Power Cable F, NIST/NRC Tests, Tests 2 and 8 
 

147

 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Power Cable F Surface Temperature

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs F-Ts-20 

CFAST Time vs Cable F Temp 

Power Cable F Surface Temperature

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs F-Ts-20 

CFAST Time vs Cable F Temp 

Figure A-46. Thermal Environment near Power Cable F, NIST/NRC Tests, Tests 4 and 10 
 

148

 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Power Cable F Surface Temperature

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs F-Ts-20 

CFAST Time vs Cable F Temp 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 2 

CFAST Time vs Cable F Flux 

Figure A-47. Thermal Environment near Power Cable F, NIST/NRC Tests, Tests 13 and 16 
 

149

 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Power Cable F Surface Temperature

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs F-Ts-20 

CFAST Time vs Cable F Temp 

Power Cable F Surface Temperature

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs F-Ts-20 

CFAST Time vs Cable F Temp 

Figure A-48. Thermal Environment near Power Cable F, NIST/NRC Tests, Tests 3 and 9 
 

150

 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Power Cable F Surface Temperature

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs F-Ts-20 

CFAST Time vs Cable F Temp 

Power Cable F Surface Temperature

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs F-Ts-20 

CFAST Time vs Cable F Temp 

Figure A-49. Thermal Environment near Power Cable F, NIST/NRC Tests, Tests 5 and 14 
 

151

 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

5

10

15

20

25

30

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Total Heat Flux to Power Cable F

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

5

10

15

20

25

Exp Time vs Cable Total Flux 2 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable F Flux 

CFAST Time vs Cable F Rad 

Power Cable F Surface Temperature

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

200

400

600

800

Exp Time vs F-Ts-20 

CFAST Time vs Cable F Temp 

Power Cable F Surface Temperature

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

200

400

600

800

Exp Time vs F-Ts-20 

CFAST Time vs Cable F Temp 

Figure A-50. Thermal Environment near Power Cable F, NIST/NRC Tests, Tests 15 and 18 
 

152

 

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

2.5

Exp Time vs Cable Rad Gauge 7

CFAST Time vs Cable G Flux 

CFAST Time vs Cable G33 Rad 

Gauge 9 inoperative

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

2.5

Exp Time vs Cable Total Flux 9 

Exp Time vs Cable Rad Gauge 10 

CFAST Time vs Cable G Flux 

CFAST Time vs Cable G33 Rad 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

CFAST Time vs Cable G31 Temp 

CFAST Time vs Cable G35 Temp 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

CFAST Time vs Cable G31 Temp 

CFAST Time vs Cable G35 Temp 

Figure A-51. Thermal Environment near Vertical Cable Tray G, NIST/NRC Tests, Tests 1 and 7 
 

153

 

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 9 

Exp Time vs Cable Rad Gauge 10 

CFAST Time vs Cable G Flux 

CFAST Time vs Cable G33 Rad 

Gauge 9 inoperative

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 9 

Exp Time vs Cable Rad Gauge 10 

CFAST Time vs Cable G Flux 

CFAST Time vs Cable G33 Rad 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

CFAST Time vs Cable G31 Temp 

CFAST Time vs Cable G35 Temp 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

CFAST Time vs Cable G31 Temp 

CFAST Time vs Cable G35 Temp 

Figure A-52. Thermal Environment near Vertical Cable Tray G, NIST/NRC Tests, Tests 2 and 8 
 

154

 

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 9 

Exp Time vs Cable Rad Gauge 10 

CFAST Time vs Cable G Flux 

CFAST Time vs Cable G33 Rad 

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 9 

Exp Time vs Cable Rad Gauge 10 

CFAST Time vs Cable G Flux 

CFAST Time vs Cable G33 Rad 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

CFAST Time vs Cable G31 Temp 

CFAST Time vs Cable G35 Temp 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

CFAST Time vs Cable G31 Temp 

CFAST Time vs Cable G35 Temp 

Figure A-53. Thermal Environment near Vertical Cable Tray G, NIST/NRC Tests, Tests 4 and 10 
 

155

 

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

12

14

Exp Time vs Cable Total Flux 9 

Exp Time vs Cable Rad Gauge 10 

CFAST Time vs Cable G Flux 

CFAST Time vs Cable G33 Rad 

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

12

14

Exp Time vs Cable Total Flux 9 

Exp Time vs Cable Rad Gauge 1 

CFAST Time vs Cable G Flux 

CFAST Time vs Cable F Rad 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

CFAST Time vs Cable G31 Temp 

CFAST Time vs Cable G35 Temp 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

CFAST Time vs Cable G31 Temp 

CFAST Time vs Cable G35 Temp 

Figure A-54. Thermal Environment near Vertical Cable Tray G, NIST/NRC Tests, Tests 13 and 16 
 

156

 

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 9 

Exp Time vs Cable Rad Gauge 10 

CFAST Time vs Cable G Flux 

CFAST Time vs Cable G33 Rad 

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Cable Total Flux 9 

Exp Time vs Cable Rad Gauge 10 

CFAST Time vs Cable G Flux 

CFAST Time vs Cable G33 Rad 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

CFAST Time vs Cable G31 Temp 

CFAST Time vs Cable G35 Temp 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

CFAST Time vs Cable G31 Temp 

CFAST Time vs Cable G35 Temp 

Figure A-55. Thermal Environment near Vertical Cable Tray G, NIST/NRC Tests, Tests 3 and 9 
 

157

 

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 9 

Exp Time vs Cable Rad Gauge 10 

CFAST Time vs Cable G Flux 

CFAST Time vs Cable G33 Rad 

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

12

Exp Time vs Cable Total Flux 9 

Exp Time vs Cable Rad Gauge 10 

CFAST Time vs Cable G Flux 

CFAST Time vs Cable G33 Rad 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

CFAST Time vs Cable G31 Temp 

CFAST Time vs Cable G35 Temp 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

350

400

450

500

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

Col 325 vs Col 336 

Col 325 vs Col 337 

Figure A-56. Thermal Environment near Vertical Cable Tray G, NIST/NRC Tests, Tests 5 and 14 
 

158

 

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Cable Total Flux 9 

Exp Time vs Cable Rad Gauge 10 

CFAST Time vs Cable G Flux 

CFAST Time vs Cable G33 Rad 

Total Heat Flux to Cable Tray G

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Cable Total Flux 9 

Exp Time vs Cable Rad Gauge 10 

CFAST Time vs Cable G Flux 

CFAST Time vs Cable G33 Rad 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

350

400

450

500

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

CFAST Time vs Cable G31 Temp 

CFAST Time vs Cable G35 Temp 

Vertical Cable Tray G Surface Temperatures

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

350

400

Exp Time vs Vertical Cable Ts-35 

Exp Time vs Vertical Cable Ts-31 

CFAST Time vs Cable G31 Temp 

CFAST Time vs Cable G35 Temp 

Figure A-57. Thermal Environment near Vertical Cable Tray G, NIST/NRC Tests, Tests 15 and 18 
 

159

iBMB Pool Fire Tests 

Targets in the iBMB pool fire test 1 were three material probes made of concrete, aerated 

concrete and steel. Sensor M29 represents the aerated concrete material while Sensors M33 and 

M34 represent the concrete and steel materials respectively. 

Figure A-58. Location of Three Slab Targets in the iBMB Pool Fire Tests 
 

160

Heat Flux to Steel Plate

ICFMP BE #4, Test 1

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

10

20

30

40

50

60

Exp Time vs WS 2 

CFAST Time vs WS2 Flux 

Steel Surface Temperature

ICFMP BE #4, Test 1

Time (s)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

500

600

Exp Time vs M 34 

CFAST Time vs WS2 Temp 

Heat Flux to Concrete

ICFMP BE #4, Test 1

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

10

20

30

40

50

60

Exp Time vs WS 3 

CFAST Time vs WS3 Flux 

Concrete Surface Temperature

ICFMP BE #4, Test 1

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

500

600

Exp Time vs M 33 

CFAST Time vs WS3 Temp 

Heat Flux to Light Concrete

ICFMP BE #4, Test 1

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

10

20

30

40

50

60

Exp Time vs WS 4 

CFAST Time vs WS4 Flux 

Light Concrete Surface Temperature

ICFMP BE #4, Test 1

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

500

600

Exp Time vs M 29 

CFAST Time vs WS4 Temp 

Figure A-59. Heat Flux and Surface Temperatures of Target Slabs, iBMB Pool Fire Test 1 
 

161

iBMB Cable Fire Tests 

A vertical cable tray was positioned near a wall opposite the fire. Heat flux gauges were inserted 

in between two bundles of cables (one containing power cables, and the other containing control 

cables). The following pages present plots of the gas temperature, heat flux, and cable surface 

temperatures at three vertical locations along the tray. 
 

162

 

Heat Flux to Cable Tray

ICFMP BE #5, Test 4

Time (min)

0 5 10 15 20

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs WS2 

Exp Time vs WS3 

Exp Time vs WS4 

CFAST Time vs WS2 Flux 

CFAST Time vs WS3 Flux 

CFAST Time vs WS4 Flux 

Power Cable Surface Temperatures

ICFMP BE #5, Test 4

Time (min)

0 5 10 15 20

Temperature (C)

0

50

100

150

200

Exp Time vs TCO 1-3 

Exp Time vs TCO 1-5 

Exp Time vs TCO 1-7 

CFAST Time vs TCO1-3 Temp 

CFAST Time vs TCO1-5 Temp 

CFAST Time vs TCO1-7 Temp 

Control Cable Surface Temperatures

ICFMP BE #5, Test 4

Time (min)

0 5 10 15 20

Temperature (C)

0

50

100

150

200

Exp Time vs TCO 3-3 

Exp Time vs TCO 3-5 

Exp Time vs TCO 3-7 

CFAST Time vs TCO3-3 Temp 

CFAST Time vs TCO3-5 Temp 

CFAST Time vs TCO3-7 Temp 

Figure A-60. Thermal Environment near Vertical Cable Tray, iBMB Cable Fire Test 4 
 

163

Table A-6. Relative Differences for Radiation and Total Heat Flux to Targets and Target Temperature 

 Radiant Heat Flux to Targets Total Heat Flux to Targets Target Temperature Rise 

 Test Cable Exp CFAST Diff Exp CFAST Diff Exp CFAST Diff 

 (kW/m2) (kW/m2) (%) (kW/m2) (kW/m2) (%) (°C) (°C) (%) 

NIST 

Test 

1 

B 1.1 1.5 37 1.9 1.7 -10 106 103 -3 

/ D 1.4 1.6 10 

NRC F 0.9 1.4 65 1.6 1.8 12 83 68 -18 

 G33 1.5 1.6 5 64 96 49 

Test 

7 

B 1.2 1.5 24.6 1.8 1.6 -12 109 102 -7 

 D 1.3 1.6 15.0 2.5 1.7 -33 87 102 17 

 F 0.8 1.4 71.2 1.5 1.7 13 90 73 -19 

 G33 1.5 1.6 5.8 1.9 1.7 -11 78 93 19 

Test 

2 

B 2.9 4.2 45.3 5.3 4.6 -12 176 144 -18 

 D 4.2 4.3 4 9.8 4.8 -52 126 146 15 

 F 2.0 3.9 96 4.8 4.6 -4 129 112 -13 

 G33 6.0 4.3 -27 107 138 30 

Test 

8 

B 2.9 4.1 41 5.6 4.6 -18 183 142 -23 

 D 3.6 4.3 20 8.5 4.7 -45 150 143 -4 

 F 1.9 3.8 98 4.9 4.5 -9 131 110 -16 

 G33 6.0 4.3 -29 6.0 4.6 -22 107 136 27 

Test 

4 

B 2.9 3.9 32 5.5 4.1 -25 149 156 5 

 D 3.3 4.0 23 7.2 4.3 -41 113 157 39 

 F 2.0 3.6 78 5.0 4.2 -17 149 115 -22 

 G33 6.0 4.0 -34 6.4 4.2 -34 125 149 19 

Test 

10 

B 2.7 3.8 43 4.9 4.1 -17 144 162 13 

 D 2.9 4.0 36 6.7 4.2 -37 132 164 24 

 F 1.9 3.6 86 4.4 4.0 -7 150 129 -14 

 G33 5.4 4.0 -27 6.2 4.2 -32 148 149 0 

Test 

13 

B 4.8 7.7 61 8.3 8.4 2 186 165 -11 

 D 6.6 8.0 22 11.2 8.7 -22 173 169 -3 

 F 2.9 7.2 147 7.3 8.1 11 143 143 0 

 G33 10.1 8.0 -20 12.2 8.6 -30 133 164 23 

Test 

16 

B 4.1 6.5 59 8.4 7.2 -14 160 166 3 

 D 4.8 6.8 41 11.7 7.4 -37 156 170 9 

 F 2.8 6.0 119 6.1 6.8 11 168 148 -12 

 G33 12.0 6.8 -43 12.2 7.3 -40 169 150 -11 

Test 

17 

B 1.3 2.1 60 2.4 2.6 10 

 D 1.5 2.2 45 3.3 2.7 -18 

 F 0.9 1.9 111 1.9 2.4 30 

 G33 2.4 2.3 -5 3.1 2.7 -13 

Test 

3 

B 4.4 4.9 10 7.1 4.9 -31 226 221 -2 

 D 9.5 5.1 -46 210 223 6 

 F 3.0 4.5 53 5.5 4.9 -12 195 160 -18 

 G33 5.4 5.5 2 6.5 5.5 -15 169 224 33 

Test 

9 

B 4.3 4.7 9 6.6 4.8 -28 228 218 -4 

 D 5.3 4.9 -8 9.1 4.9 -46 220 219 -1 

 F 2.7 4.3 59 5.1 4.7 -7 195 156 -20 

 G33 5.2 5.3 2 6.4 5.3 -17 166 221 33 

Test 

5 

B 3.9 3.6 -7 6.9 3.6 -47 150 183 22 

 D 4.8 3.7 -22 8.5 3.8 -56 132 184 39 

 F 2.6 3.3 25 6.4 3.6 -44 175 128 -27 
 

164

 Radiant Heat Flux to Targets Total Heat Flux to Targets Target Temperature Rise 

 Test Cable Exp CFAST Diff Exp CFAST Diff Exp CFAST Diff 

 (kW/m2) (kW/m2) (%) (kW/m2) (kW/m2) (%) (°C) (°C) (%) 

 G33 5.4 4.2 -23 6.7 4.2 -37 161 190 18 

Test 

14 

B 2.8 4.1 46 3.8 4.3 12 199 207 4 

 D 6.1 4.4 -27 178 208 17 

 F 2.1 3.9 83 3.5 4.3 26 171 145 -15 

 G33 10.5 7.3 -31 10.9 7.3 -33 270 262 -3 

Test 

15 

B 46.5 3.9 -92 57.7 4.0 -93 416 207 -50 

 D 20.9 4.2 -80 243 209 -14 

 F 18.3 3.6 -80 23.9 4.0 -83 669 155 -77 

 G33 3.7 7.0 89 5.1 7.0 37 161 263 63 

Test 

18 

B 5.2 5.1 -3 7.6 5.1 -33 236 227 -4 

 D 7.8 5.0 -36 217 221 2 

 F 5.2 5.7 10 8.7 5.9 -32 232 188 -19 

 G33 2.8 4.4 54 4.4 4.5 1 

iBMB Test 

1 

WS 2 27.2 36.5 34 356 360 1 

Pool WS 3 46.6 37.3 -20 308 412 34 

Fire WS 4 32.4 35.8 10 489 514 5 

iBMB 

Test 

4 

WS 2 / TCO 1-3 3.6 1.7 -44 87 67 -23 

Cable TCO 2-3 112 85 -24 

Fire WS 3 / TCO 1-5 96.9 2.2 -98 110 88 -20 

 TCO 2-5 146 115 -22 

 WS 4 / TCO 1-7 5.7 2.2 -62 107 87 -18 

 TCO 2-7 140 114 -19 
 

165

B.9 Heat Flux and Surface Temperature of Compartment Walls 

Heat fluxes and surfaces temperatures at compartment walls, floor, and ceiling are available from 

NIST/NRC tests. This category is similar to that of the previous section, “Heat Flux and Surface 

Temperature of Targets,” with the exception that the focus here is on compartment walls, 

ceilings, and floors. 

NIST/NRC TESTS 

Thirty-six heat flux gauges were positioned at various locations on all four walls of the 

compartment, plus the ceiling and floor. Comparisons between measured and predicted heat 

fluxes and surface temperatures are shown on the following pages for a selected number of 

locations. More than half of the measurement points were in roughly the same relative location 

to the fire and hence the measurements and predictions were similar. For this reason, data for the 

east and north walls are shown because the data from the south and west walls are comparable. 

Data from the south wall are used in cases where the corresponding instrument on the north wall 

failed, or in cases where the fire was positioned close to the south wall. The heat flux gauges 

used on the compartment walls measured the net (not total) heat flux. 
 

166

Long Wall Heat Flux

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

Exp Time vs North U-1 

Exp Time vs South U-4 

CFAST Time vs N U-1 Flux 

CFAST Time vs S U-4 Flux 

Long Wall Temperatures

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

Exp Time vs TC North U-1-2 

Exp Time vs TC South U-4-2 

CFAST Time vs N U-1 Temp 

CFAST Time vs S U-4 Temp 

Long Wall Heat Flux

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

Exp Time vs North U-1 

Exp Time vs South U-4 

CFAST Time vs N U-1 Flux 

CFAST Time vs S U-4 Flux 

Long Wall Temperatures

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

Exp Time vs TC North U-1-2 

Exp Time vs TC South U-4-2 

CFAST Time vs N U-1 Temp 

CFAST Time vs S U-4 Temp 

Long Wall Heat Flux

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs North U-1 

Exp Time vs South U-4 

CFAST Time vs N U-1 Flux 

CFAST Time vs S U-4 Flux 

Long Wall Temperatures

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs TC North U-1-2 

Exp Time vs TC South U-4-2 

CFAST Time vs N U-1 Temp 

CFAST Time vs S U-4 Temp 

Long Wall Heat Flux

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs North U-1 

Exp Time vs North U-4 

CFAST Time vs N U-1 Flux 

CFAST Time vs N U-4 Flux 

Long Wall Temperatures

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs TC North U-1-2 

Exp Time vs TC North U-4-2 

CFAST Time vs N U-1 Temp 

CFAST Time vs N U-4 Temp 

Figure A-61. Long Wall Heat Flux and Surface Temperature, NIST/NRC Tests 
 

167

Long Wall Heat Flux

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs North U-1 

Exp Time vs North U-4 

CFAST Time vs N U-1 Flux 

CFAST Time vs N U-4 Flux 

Long Wall Temperatures

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs TC North U-1-2 

Exp Time vs TC North U-4-2 

CFAST Time vs N U-1 Temp 

CFAST Time vs N U-4 Temp 

Long Wall Heat Flux

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs North U-1 

Exp Time vs North U-4 

CFAST Time vs N U-1 Flux 

CFAST Time vs N U-4 Flux 

Long Wall Temperatures

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs TC North U-1-2 

Exp Time vs TC North U-4-2 

CFAST Time vs N U-1 Temp 

CFAST Time vs N U-4 Temp 

Long Wall Heat Flux

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs N U-1 Flux 

CFAST Time vs N U-4 Flux 

Flux Gauge Inoperative

Long Wall Temperatures

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC North U-1-2 

Exp Time vs TC North U-4-2 

CFAST Time vs N U-1 Temp 

CFAST Time vs N U-4 Temp 

Long Wall Heat Flux

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

CFAST Time vs N U-1 Flux 

CFAST Time vs N U-4 Flux 

Flux Gauge Inoperative

Long Wall Temperatures

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC North U-1-2 

Exp Time vs TC North U-4-2 

CFAST Time vs N U-1 Temp 

CFAST Time vs N U-4 Temp 

Figure A-62. Long Wall Heat Flux and Surface Temperature, NIST/NRC Tests 
 

168

Long Wall Heat Flux

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

2.5

3.0

Exp Time vs North U-1 

Exp Time vs North U-4 

CFAST Time vs N U-1 Flux 

CFAST Time vs N U-4 Flux 

Long Wall Temperatures

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

Exp Time vs TC North U-1-2 

Exp Time vs TC North U-4-2 

CFAST Time vs N U-1 Temp 

CFAST Time vs N U-4 Temp 

The following graphs are from open-door tests

Long Wall Heat Flux

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs North U-1 

Exp Time vs North U-4 

CFAST Time vs N U-1 Flux 

CFAST Time vs N U-4 Flux 

Long Wall Temperatures

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC North U-1-2 

Exp Time vs TC North U-4-2 

CFAST Time vs N U-1 Temp 

CFAST Time vs N U-4 Temp 

Long Wall Heat Flux

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs North U-1 

Exp Time vs North U-4 

CFAST Time vs N U-1 Flux 

CFAST Time vs N U-4 Flux 

Long Wall Temperatures

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC North U-1-2 

Exp Time vs TC North U-4-2 

CFAST Time vs N U-1 Temp 

CFAST Time vs N U-4 Temp 

Figure A-63. Long Wall Heat Flux and Surface Temperature, NIST/NRC Tests 
 

169

Long Wall Heat Flux

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs North U-1 

Exp Time vs North U-4 

CFAST Time vs N U-1 Flux 

CFAST Time vs N U-4 Flux 

Long Wall Temperatures

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs TC North U-1-2 

Exp Time vs TC North U-4-2 

CFAST Time vs N U-1 Temp 

CFAST Time vs N U-4 Temp 

Long Wall Heat Flux

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs North U-1 

Exp Time vs North U-4 

CFAST Time vs N U-1 Flux 

CFAST Time vs N U-4 Flux 

Long Wall Temperatures

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs TC North U-1-2 

Exp Time vs TC North U-4-2 

CFAST Time vs N U-1 Temp 

CFAST Time vs N U-4 Temp 

Long Wall Heat Flux

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs South U-1 

Exp Time vs South U-3

CFAST Time vs S U-1 Flux 

CFAST Time vs S U-3 Flux 

Long Wall Temperatures

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC South U-1-2 

Exp Time vs TC South U-3-2 

CFAST Time vs S U-1 Temp 

CFAST Time vs S U-3 Temp 

Long Wall Heat Flux

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs South U-1

Exp Time vs South U-4 

CFAST Time vs S U-1 Flux 

CFAST Time vs S U-4 Flux 

Long Wall Temperatures

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

350

400

Exp Time vs TC South U-1-2 

Exp Time vs TC South U-4-2 

CFAST Time vs S U-1 Temp 

CFAST Time vs S U-4 Temp 

Figure A-64. Long Wall Heat Flux and Surface Temperature, NIST/NRC Tests 
 

170

Short Wall Heat Flux

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

Exp Time vs East U-1 

Exp Time vs East U-2 

CFAST Time vs E U-1 Flux 

CFAST Time vs E U-2 Flux 

Short Wall Temperatures

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

Exp Time vs TC East U-1-2 

Exp Time vs TC East U-2-2 

CFAST Time vs E U-1 Temp 

CFAST Time vs E U-2 Temp 

Short Wall Heat Flux

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

Exp Time vs East U-3 

Exp Time vs East U-2 

CFAST Time vs E U-3 Flux 

CFAST Time vs E U-2 Flux 

Short Wall Temperatures

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

Exp Time vs TC East U-3-2 

Exp Time vs TC East U-2-2 

CFAST Time vs E U-3 Temp 

CFAST Time vs E U-2 Temp 

Short Wall Heat Flux

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs East U-1 

Exp Time vs East U-2 

CFAST Time vs E U-1 Flux 

CFAST Time vs E U-2 Flux 

Short Wall Temperatures

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs TC East U-1-2 

Exp Time vs TC East U-2-2 

CFAST Time vs E U-1 Temp 

CFAST Time vs E U-2 Temp 

Short Wall Heat Flux

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs East U-1 

Exp Time vs East U-2 

CFAST Time vs E U-1 Flux 

CFAST Time vs E U-2 Flux 

Short Wall Temperatures

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC East U-1-2 

Exp Time vs TC East U-2-2 

CFAST Time vs E U-1 Temp 

CFAST Time vs E U-2 Temp 

Figure A-65. Short Wall Heat Flux and Surface Temperature, NIST/NRC Tests 
 

171

Short Wall Heat Flux

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs East U-1 

Exp Time vs East U-2 

CFAST Time vs E U-1 Flux 

CFAST Time vs E U-2 Flux 

Short Wall Temperatures

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs TC East U-1-2 

Exp Time vs TC East U-2-2 

CFAST Time vs E U-1 Temp 

CFAST Time vs E U-2 Temp 

Short Wall Heat Flux

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs East U-3 

Exp Time vs East U-2 

CFAST Time vs E U-3 Flux 

CFAST Time vs E U-2 Flux 

Short Wall Temperatures

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC East U-3-2 

Exp Time vs TC East U-2-2 

CFAST Time vs E U-3 Temp 

CFAST Time vs E U-2 Temp 

Short Wall Heat Flux

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs E U-1 Flux 

CFAST Time vs E U-4 Flux 

Flux Gauge Inoperative

Short Wall Temperatures

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC East U-1-2 

Exp Time vs TC East U-4-2 

CFAST Time vs E U-1 Temp 

CFAST Time vs E U-4 Temp 

Short Wall Heat Flux

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

CFAST Time vs E U-1 Flux 

CFAST Time vs E U-2 Flux 

Flux Gauge Inoperative

Short Wall Temperatures

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC East U-1-2 

Exp Time vs TC East U-2-2 

CFAST Time vs E U-1 Temp 

CFAST Time vs E U-2 Temp 

Figure A-66. Short Wall Heat Flux and Surface Temperature, NIST/NRC Tests 
 

172

Short Wall Heat Flux

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

2.5

3.0

Exp Time vs East U-3 

Exp Time vs East U-2 

CFAST Time vs E U-3 Flux 

CFAST Time vs E U-2 Flux 

Short Wall Temperatures

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

20

40

60

80

100

Exp Time vs TC East U-3-2 

Exp Time vs TC East U-2-2 

CFAST Time vs E U-3 Temp 

CFAST Time vs E U-2 Temp 

The following graphs are from open-door tests

Short Wall Heat Flux

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs East U-1 

Exp Time vs East U-2 

CFAST Time vs E U-1 Flux 

CFAST Time vs E U-2 Flux 

Short Wall Temperatures

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC East U-1-2 

Exp Time vs TC East U-2-2 

CFAST Time vs E U-1 Temp 

CFAST Time vs E U-2 Temp 

Short Wall Heat Flux

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6 Exp Time vs East U-3 

Exp Time vs East U-4 

CFAST Time vs E U-3 Flux 

CFAST Time vs E U-4 Flux 

Flux Gauge E U-4 Inoperative

Short Wall Temperatures

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC East U-3-2 

Exp Time vs TC East U-4-2 

CFAST Time vs E U-3 Temp 

CFAST Time vs E U-4 Temp 

Figure A-67. Short Wall Heat Flux and Surface Temperature, NIST/NRC Tests 
 

173

Short Wall Heat Flux

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs East U-1 

Exp Time vs East U-2 

CFAST Time vs E U-1 Flux 

CFAST Time vs E U-2 Flux 

Short Wall Temperatures

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC East U-1-2 

Exp Time vs TC East U-2-2 

CFAST Time vs E U-1 Temp 

CFAST Time vs E U-2 Temp 

Short Wall Heat Flux

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs East U-3 

Exp Time vs East U-2 

Col 325 vs Col 368 

Col 325 vs Col 367 

Short Wall Temperatures

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC East U-3-2 

Exp Time vs TC East U-2-2 

Col 325 vs Col 345 

Col 325 vs Col 344 

Short Wall Heat Flux

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs East U-3 

Exp Time vs East U-2 

CFAST Time vs E U-3 Flux 

CFAST Time vs E U-2 Flux 

Short Wall Temperatures

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC East U-3-2 

Exp Time vs TC East U-2-2 

CFAST Time vs E U-3 Temp 

CFAST Time vs E U-2 Temp 

Short Wall Heat Flux

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs East U-3 

Exp Time vs East U-2 

CFAST Time vs E U-3 Flux 

CFAST Time vs E U-2 Flux 

Short Wall Temperatures

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC East U-3-2 

Exp Time vs TC East U-2-2 

CFAST Time vs E U-3 Temp 

CFAST Time vs E U-2 Temp 

Figure A-68. Short Wall Heat Flux and Surface Temperature, NIST/NRC Tests 
 

174

Ceiling Heat Flux

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

Exp Time vs Ceiling U-1 

Exp Time vs Ceiling U-4 

CFAST Time vs C-1 Flux 

CFAST Time vs C-4 Flux 

Ceiling Temperatures

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC Ceiling U-1-2 

Exp Time vs TC Ceiling C-4-2 

CFAST Time vs C-1 Temp 

CFAST Time vs C-4 Temp 

Ceiling Heat Flux

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

Exp Time vs Ceiling U-1 

Exp Time vs Ceiling U-4 

CFAST Time vs C-1 Flux 

CFAST Time vs C-4 Flux 

Gauge U-4 Inoperative

Ceiling Temperatures

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

Exp Time vs TC Ceiling U-1-2 

Exp Time vs TC Ceiling C-4-2 

CFAST Time vs C-1 Temp 

CFAST Time vs C-4 Temp 

Ceiling Heat Flux

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

5

10

15

Exp Time vs Ceiling U-1 

Exp Time vs Ceiling U-4 

CFAST Time vs C-1 Flux 

CFAST Time vs C-4 Flux 

Ceiling Temperatures

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs TC Ceiling U-1-2 

Exp Time vs TC Ceiling C-4-2 

CFAST Time vs C-1 Temp 

CFAST Time vs C-4 Temp 

Ceiling Heat Flux

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

5

10

15

Exp Time vs Ceiling U-1 

Exp Time vs Ceiling U-4 

CFAST Time vs C-1 Flux 

CFAST Time vs C-4 Flux 

Ceiling Temperatures

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs TC Ceiling U-1-2 

Exp Time vs TC Ceiling C-4-2 

CFAST Time vs C-1 Temp 

CFAST Time vs C-4 Temp 

Figure A-69. Ceiling Heat Flux and Surface Temperature, NIST/NRC Tests 
 

175

Ceiling Heat Flux

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Ceiling U-1 

Exp Time vs Ceiling U-4 

CFAST Time vs C-1 Flux 

CFAST Time vs C-4 Flux 

Ceiling Temperatures

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

Exp Time vs TC Ceiling U-1-2 

Exp Time vs TC Ceiling C-4-2 

CFAST Time vs C-1 Temp 

CFAST Time vs C-4 Temp 

Ceiling Heat Flux

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Ceiling U-1 

Exp Time vs Ceiling U-4 

CFAST Time vs C-1 Flux 

CFAST Time vs C-4 Flux 

Gauge U-4 Inoperative

Ceiling Temperatures

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

Exp Time vs TC Ceiling U-1-2 

Exp Time vs TC Ceiling C-4-2 

CFAST Time vs C-1 Temp 

CFAST Time vs C-4 Temp 

Ceiling Heat Flux

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs C-7 Flux 

CFAST Time vs C-5 Flux 

Flux Gauge Inoperative

Ceiling Temperatures

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

500

600

Exp Time vs TC Ceiling C-7-2 

Exp Time vs TC Ceiling C-5-2 

CFAST Time vs C-7 Temp 

CFAST Time vs C-5 Temp 

Ceiling Heat Flux

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

CFAST Time vs C-7 Flux 

CFAST Time vs C-5 Flux 

Flux Gauge Inoperative

Ceiling Temperatures

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

500

Exp Time vs TC Ceiling C-7-2 

Exp Time vs TC Ceiling C-5-2 

CFAST Time vs C-7 Temp 

CFAST Time vs C-5 Temp 

 Figure A-70. Ceiling Heat Flux and Surface Temperature, NIST/NRC Tests 
 

176

Ceiling Heat Flux

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

CFAST Time vs C-1 Flux 

CFAST Time vs C-4 Flux 

Gauges Inoperative

Ceiling Temperatures

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

Exp Time vs TC Ceiling U-1-2 

Exp Time vs TC Ceiling C-4-2 

CFAST Time vs C-1 Temp 

CFAST Time vs C-4 Temp 

The following graphs are from open-door tests

Ceiling Heat Flux

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

12

Exp Time vs Ceiling U-1 

Exp Time vs Ceiling U-4 

CFAST Time vs C-1 Flux 

CFAST Time vs C-4 Flux 

Ceiling Temperatures

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs TC Ceiling U-1-2 

Exp Time vs TC Ceiling C-4-2 

CFAST Time vs C-1 Temp 

CFAST Time vs C-4 Temp 

Ceiling Heat Flux

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

5

10

15

20

Exp Time vs Ceiling U-2 

Exp Time vs Ceiling U-4 

CFAST Time vs C-2 Flux 

CFAST Time vs C-4 Flux 

Ceiling Temperatures

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs TC Ceiling C-2-1 

Exp Time vs TC Ceiling C-4-2 

CFAST Time vs C-2 Temp 

CFAST Time vs C-4 Temp 

Figure A-71. Ceiling Heat Flux and Surface Temperature, NIST/NRC Tests 
 

177

Ceiling Heat Flux

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

Exp Time vs Ceiling U-1 

Exp Time vs Ceiling U-5 

CFAST Time vs C-1 Flux 

CFAST Time vs C-5 Flux 

Ceiling Temperatures

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs TC Ceiling U-1-2 

Exp Time vs TC Ceiling C-5-2 

CFAST Time vs C-1 Temp 

CFAST Time vs C-5 Temp 

Ceiling Heat Flux

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Ceiling U-1 

Exp Time vs Ceiling U-5 

Col 325 vs Col 370 

Col 325 vs Col 373 

Ceiling Temperatures

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs TC Ceiling U-1-2 

Exp Time vs TC Ceiling C-5-2 

Col 325 vs Col 347 

Col 325 vs Col 350 

Ceiling Heat Flux

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Ceiling U-1 

Exp Time vs Ceiling U-4 

CFAST Time vs C-1 Flux 

CFAST Time vs C-4 Flux 

Gauges Inoperative

Ceiling Temperatures

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

100

200

300

400

Exp Time vs TC Ceiling U-1-2 

Exp Time vs TC Ceiling C-4-2 

CFAST Time vs C-1 Temp 

CFAST Time vs C-4 Temp 

Ceiling Heat Flux

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Ceiling U-1 

Exp Time vs Ceiling U-4 

CFAST Time vs C-1 Flux 

CFAST Time vs C-4 Flux 

Gauge U-4 Inoperative

Ceiling Heat Flux

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Ceiling U-1 

Exp Time vs Ceiling U-4 

CFAST Time vs C-1 Flux 

CFAST Time vs C-4 Flux 

Gauge U-4 Inoperative

Figure A-72. Ceiling Heat Flux and Surface Temperature, NIST/NRC Tests 
 

178

Floor Heat Flux

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

2.5

3.0

Exp Time vs Floor U-1 

Exp Time vs Floor U-4 

CFAST Time vs F-1 Flux 

CFAST Time vs F-4 Flux 

Floor Temperatures

ICFMP BE #3, Test 1

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-4-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-4 Temp 

Floor Heat Flux

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

2.5

3.0 Exp Time vs Floor U-1 

Exp Time vs Floor U-4 

CFAST Time vs F-1 Flux 

CFAST Time vs F-4 Flux 

Floor Temperatures

ICFMP BE #3, Test 7

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-4-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-4 Temp 

Floor Heat Flux

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Floor U-1 

Exp Time vs Floor U-4 

CFAST Time vs F-1 Flux 

CFAST Time vs F-4 Flux 

Floor Temperatures

ICFMP BE #3, Test 2

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-4-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-4 Temp 

Floor Heat Flux

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Floor U-1 

Exp Time vs Floor U-4 

CFAST Time vs F-1 Flux 

CFAST Time vs F-4 Flux 

Floor Temperatures

ICFMP BE #3, Test 8

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-4-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-4 Temp 

Figure A-73. Floor Heat Flux and Surface Temperature, NIST/NRC Tests 
 

179

Floor Heat Flux

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Floor U-1 

Exp Time vs Floor U-4 

CFAST Time vs F-1 Flux 

CFAST Time vs F-4 Flux 

Floor Temperatures

ICFMP BE #3, Test 4

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-4-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-4 Temp 

Floor Heat Flux

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Floor U-1 

Exp Time vs Floor U-4 

CFAST Time vs F-1 Flux 

CFAST Time vs F-4 Flux 

Floor Temperatures

ICFMP BE #3, Test 10

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-4-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-4 Temp 

Floor Heat Flux

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

CFAST Time vs F-1 Flux 

CFAST Time vs F-2 Flux 

Flux Gauge Inoperative

Floor Temperatures

ICFMP BE #3, Test 13

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-2-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-2 Temp 

Floor Heat Flux

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

2

4

6

8

CFAST Time vs F-1 Flux 

CFAST Time vs F-2 Flux 

Flux Gauge Inoperative

Floor Temperatures

ICFMP BE #3, Test 16

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-2-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-2 Temp 

Figure A-74. Floor Heat Flux and Surface Temperature, NIST/NRC Tests 
 

180

Floor Heat Flux

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

Exp Time vs Floor U-1 

Exp Time vs Floor U-2 

CFAST Time vs F-1 Flux 

CFAST Time vs F-2 Flux 

Floor Temperatures

ICFMP BE #3, Test 17

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

20

40

60

80

100

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-2-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-2 Temp 

The following graphs are from open-door tests

Floor Heat Flux

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

Exp Time vs Floor U-1 

Exp Time vs Floor U-2 

CFAST Time vs F-1 Flux 

CFAST Time vs F-2 Flux 

Floor Temperatures

ICFMP BE #3, Test 3

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-2-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-2 Temp 

Floor Heat Flux

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

Exp Time vs Floor U-1 

Exp Time vs Floor U-2 

CFAST Time vs F-1 Flux 

CFAST Time vs F-2 Flux 

Floor Temperatures

ICFMP BE #3, Test 9

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-2-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-2 Temp 

Figure A-75. Floor Heat Flux and Surface Temperature, NIST/NRC Tests 
 

181

Floor Heat Flux

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

)

0

2

4

6

8

10

12

Exp Time vs Floor U-1 

Exp Time vs Floor U-4 

CFAST Time vs F-1 Flux 

CFAST Time vs F-4 Flux 

Floor Temperatures

ICFMP BE #3, Test 5

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300 Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-4-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-4 Temp 

Floor Heat Flux

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

Exp Time vs Floor U-1 

Exp Time vs Floor U-2 

CFAST Time vs F-1 Flux 

CFAST Time vs F-2 Flux 

Floor Temperatures

ICFMP BE #3, Test 14

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-4-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-2 Temp 

Floor Heat Flux

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0

1

2

3

4

5

6

Exp Time vs Floor U-1 

Exp Time vs Floor U-2 

CFAST Time vs F-1 Flux 

CFAST Time vs F-2 Flux 

Floor Temperatures

ICFMP BE #3, Test 15

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-2-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-2 Temp 

Floor Heat Flux

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Heat Flux (kW/m2

) 0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Exp Time vs Floor U-1 

Exp Time vs Floor U-2 

CFAST Time vs F-1 Flux 

CFAST Time vs F-2 Flux 

Floor Temperatures

ICFMP BE #3, Test 18

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

50

100

150

200

250

300

Exp Time vs TC Floor U-1-2 

Exp Time vs TC Floor U-2-2 

CFAST Time vs F-1 Temp 

CFAST Time vs F-2 Temp 

Figure A-76. Floor Heat Flux and Surface Temperature, NIST/NRC Tests 
 

182

 iBMB Pool Fire Tests 

Thermocouples are positioned against the back wall of the compartment. Because the fire leans 

toward the back wall, temperatures measured by the thermocouples are considerably higher than 

those in other tests and higher than those predicted by the CFAST model that does not include 

the effects of an non-symmetric, wind-aided plume. 

Wall Surface Temperature

ICFMP BE #4, Test 1

Time (min)

0 5 10 15 20 25 30

Temperature (C)

0

200

400

600

800

Exp Time vs M 19 

Exp Time vs M 20 

CFAST Time vs M19 Temp 

CFAST Time vs M20 Temp 

Figure A-77. Back Wall Surface Temperature, iBMB Pool Fire Test 1 
 

183

iBMB Cable Fire Tests 

Wall surface temperatures are measured in two locations in the iBMB cable fire test series. The 

thermocouples labeled TW 1-x (Wall Chain 1) are against the back wall; those labeled TW 2-x 

(Wall Chain 2) are behind the vertical cable tray. Seven thermocouples are in each chain, spaced 

0.8 m apart. In figure A-78, the lowest (1), middle (4), and highest (7) locations are used for 

comparison. 

Back Wall Temperature

ICFMP BE #5, Test 4

Time (min)

0 5 10 15 20

Temperature (C)

0

25

50

75

100

125

Exp Time vs TW 1-1 

Exp Time vs TW 1-4 

Exp Time vs TW 1-7 

CFAST Time vs TW1-1 Temp 

CFAST Time vs TW1-4 Temp 

CFAST Time vs TW1-7 Temp 

Side Wall Temperature (behind cables)

ICFMP BE #5, Test 4

Time (min)

0 5 10 15 20

Temperature (C)

0

25

50

75

100

125

Exp Time vs TW 2-1 

Exp Time vs TW 2-4 

Exp Time vs TW 2-7 

CFAST Time vs TW2-1 Temp 

CFAST Time vs TW2-4 Temp 

CFAST Time vs TW2-7 Temp 

Figure A-78. Back and Side Wall Surface Temperatures, iBMB Cable Fire Test 1

 

185

Table A-7. Relative Differences for Surface Heat Flux and Temperature 

 Total Flux to Surface Surface Temperature 

Series Test Measurement 

Position 

Exp CFAST Diff Exp CFAST Diff 

 (kW/m2) (kW/m2) (%) (°C) (°C) (%) 

NIST / 

NRC 

Test 1 Long Wall 1.4 1.7 21 54 89 64 

 1.8 1.7 -6 68 89 31 

 Short Wall 1.3 1.7 33 55 89 60 

 1.7 1.7 -3 71 89 26 

 Floor 0.9 1.4 48 38 71 86 

 2.4 1.3 -44 77 69 -11 

 Ceiling 1.9 1.7 -12 81 92 14 

 3.8 1.7 -56 176 91 -49 

 Test 7 Long Wall 1.4 1.6 19 53 87 63 

 1.9 1.6 -14 70 87 23 

 Short Wall 1.2 1.6 34 55 86 58 

 1.8 1.6 -9 70 87 24 

 Floor 0.9 1.3 49 36 69 89 

 2.3 1.3 -44 78 67 -14 

 Ceiling 1.9 1.7 -14 80 89 12 

 191 88 -54 

 Test 2 Long Wall 3.8 4.4 17 96 150 57 

 4.5 4.3 -4 120 151 26 

 Short Wall 3.6 4.4 21 110 150 37 

 4.6 4.4 -5 125 151 20 

 Floor 2.6 3.7 41 74 127 71 

 8.9 3.5 -60 156 124 -21 

 Ceiling 5.6 4.5 -21 148 154 4 

 14.5 4.3 -70 308 152 -51 

 Test 8 Long Wall 3.8 4.3 13 95 149 57 

 3.3 4.3 31 132 149 13 

 Short Wall 2.5 4.3 76 109 148 36 

 4.7 4.3 -8 125 149 19 

 Floor 2.6 3.6 40 71 125 75 

 8.6 3.5 -60 148 121 -18 

 Ceiling 6.1 4.4 -28 148 153 3 

 12.9 4.3 -67 325 150 -54 

 Test 4 Long Wall 3.4 4.0 16 97 150 54 

 3.5 4.0 13 146 152 4 

 Short Wall 3.3 4.0 21 106 149 41 

 4.0 3.9 -1 121 150 24 

 Floor 2.5 3.3 35 76 130 70 

 8.5 3.2 -62 152 127 -16 

 Ceiling 5.1 4.0 -21 147 153 4 

 6.0 4.0 -34 180 153 -15 

 Test 10 Long Wall 3.3 3.9 18 94 150 59 

 3.5 3.9 13 163 151 -7 
 

186

 Total Flux to Surface Surface Temperature 

Series Test Measurement 

Position 

Exp CFAST Diff Exp CFAST Diff 

 (kW/m2) (kW/m2) (%) (°C) (°C) (%) 

 Short Wall 3.1 3.9 26 106 149 41 

 3.9 3.9 1 117 150 28 

 Floor 2.3 3.3 45 71 130 83 

 7.9 3.2 -59 158 127 -20 

 Ceiling 4.8 4.0 -17 138 153 11 

 221 153 -31 

 Test 13 Long Wall 110 195 77 

 199 198 -1 

 Short Wall 127 194 53 

 145 196 35 

 Floor 89 166 87 

 149 161 8 

 Ceiling 319 197 -38 

 498 197 -60 

 Test 16 Long Wall 107 175 64 

 217 180 -17 

 Short Wall 123 175 42 

 141 176 24 

 Floor 80 148 85 

 146 144 -1 

 Ceiling 284 178 -37 

 441 180 -59 

 Test 17 Long Wall 1.5 2.1 45 39 53 36 

 0.9 2.3 468 82 65 -20 

 Short Wall 1.6 2.1 35 56 52 -9 

 1.9 2.1 11 61 54 -11 

 Floor 0.9 1.4 62 24 34 40 

 1.5 1.3 -11 52 33 -37 

 Ceiling 69 58 -16 

 230 65 -72 

 Test 3 Long Wall 3.5 4.5 27 114 187 64 

 4.3 5.0 16 172 203 18 

 Short Wall 2.5 3.6 42 87 152 74 

 4.4 4.6 3 146 191 31 

 Floor 2.0 3.2 62 54 143 166 

 4.1 3.1 -24 119 139 17 

 Ceiling 4.6 4.7 1 155 194 25 

 9.9 4.8 -52 287 197 -31 

 Test 9 Long Wall 3.4 4.3 25 113 184 63 

 4.2 4.8 15 178 200 12 

 Short Wall 2.4 3.4 42 88 148 68 

 135 188 39 

 Floor 1.9 3.0 59 53 139 161 

 3.9 2.9 -25 122 135 10 

 Ceiling 5.5 4.5 -18 204 191 -6 
 

187

 Total Flux to Surface Surface Temperature 

Series Test Measurement 

Position 

Exp CFAST Diff Exp CFAST Diff 

 (kW/m2) (kW/m2) (%) (°C) (°C) (%) 

 9.4 4.6 -51 290 194 -33 

 Test 5 Long Wall 2.7 3.1 14 94 146 55 

 3.8 3.7 -2 155 168 9 

 Short Wall 2.0 2.5 27 71 116 62 

 3.3 3.1 -5 118 148 26 

 Floor 1.4 2.2 56 42 107 157 

 10.1 2.1 -79 171 104 -39 

 Ceiling 3.4 3.2 -6 125 151 21 

 6.7 3.4 -49 263 159 -40 

 Test 14 Long Wall 3.5 4.3 23 114 184 61 

 8.1 5.7 -30 255 222 -13 

 Short Wall 2.4 3.5 49 87 149 72 

 4.5 4.5 0 148 189 28 

 Floor 1.9 3.1 64 52 141 169 

 3.0 3.0 1 104 137 32 

 Ceiling 4.7 4.5 -3 158 192 22 

 9.0 4.8 -46 352 200 -43 

 Test 15 Long Wall 3.6 4.1 12 220 183 -17 

 7.5 4.2 -44 205 188 -9 

 Short Wall 2.6 3.3 25 96 145 50 

 4.7 4.2 -10 151 187 24 

 Floor 1.9 2.9 46 52 137 161 

 5.2 2.8 -47 132 132 1 

 Ceiling 157 191 22 

 287 186 -35 

 Test 18 Long Wall 3.4 4.3 25 118 185 56 

 312 248 -21 

 Short Wall 2.6 3.5 36 94 154 64 

 4.7 4.5 -4 153 190 24 

 Floor 1.8 3.1 74 50 141 185 

 3.1 3.0 -2 107 137 29 

 Ceiling 4.5 4.5 2 145 193 33 

 250 194 -23 

iBMB 

Pool 

Test 1 M 19 596 546 -8 

Fire M 20 722 238 -67 

iBMB Test 4 TW 1-1 56 37 -34 

Cable TW 2-1 4 24 441 

Fire TW 1-4 87 36 -58 

 TW 2-4 68 35 -49 

 TW 1-7 86 37 -57 

 TW 2-7 72 37 -49