Evaluation of the Computer Fire Model DETACT-QS

Description

​This engineering practice Guide, based on the DETACT-QS program, describes a model for predicting the response time of ceiling-mounted heat detectors/sprinklers and smoke detectors, installed under large unobstructed ceilings, for fires with user-defined, time-dependent heat release rate curves. The Guide provides information on the technical features, theoretical basis, assumptions, limitations, and sensitivities as well as guidance on the use of DETACT-QS. Evaluation is based on comparing predictions from DETACT-QS with results from full-scale fire experiments conducted in compartments with ceiling heights ranging from 2.44 m (8 ft) to 12.2 m (40 ft) and peak fire heat release rates ranging from 150 kW to 3.8 MW. Use of this model with building geometries or fire characteristics other than those used in this evaluation may require further evaluation or testing. The SFPE Task Group on Computer Model Evaluation Acknowledgment Contents List of Figures List of Tables Introduction Disclaimer Purpose Model Description Definitions Model Uses and Predictions Type of Model Model Complexity Physics of Model Minimum Hardware Requirements Operating System Model Assumptions Input Data Required Property Data Principal Publications Supporting DETACT-QS Scenarios for Which Evaluation Is Sought Quantities Predicted by the Model (Output) Degree of Accuracy Variability and Uncertainty of Fire Test Data Variability and Uncertainty in the Model Variability and Uncertainty of Model Input Parameters Overall Degree of Accuracy Required Theoretical Basis for the Model Inputs for DETACT-QS Algorithm Derivation of the Sprinkler Response Equation Solution in DETACT-QS Mathematical and Numerical Robustness Code Evaluation Detector Temperature Time to Activation Independent Comparison of DETACT-QS Results Summary Model Sensitivity Variables Acceptable Range of Values of Input Parameters Quantification of Sensitivity Sensitivity Analysis: Phase One Sensitivity Analysis: Phase Two Sensitivity Analysis: Phase Three Cautions Model Inputs Evaluation Scenarios 1–6 Geometry and Materials Fire Source Instrumentation Evaluation Scenario 7 Evaluation Scenarios 8–16 Geometry and Materials Fire Source Instrumentation Property Data Numerical Constants Model Evaluation Evaluation Scenarios 1 Through 6—Results Scenario 1—3.0 M Ceiling Height Scenario 2—4.6 M Ceiling Height Scenario 3—6.1 M Ceiling Height Scenario 4—7.6 M Ceiling Height Scenario 5—10.7 M Ceiling Height Scenario 6—12.2 M Ceiling Height Creation of a Hot Layer During Testing Evaluation Scenario 7 Plume and Ceiling Jet Temperature Correlation Analysis Evaluation Scenarios 8 Through 16 Summary of Analysis Addressing Uncertainty and Variability by Use of Multiplication Factors Limitations/User Guidelines Limitations Use of DETACT-QS to Model Smoke Detector Activation Uncertainty when Using DETACT-QS Appendices Appendix A: Mathematical Solver Worksheet—Independent Solutions for DETACT-QS Response Introduction Solution Definitions of Variables Fire Specification Ceiling Jet Temperature Ceiling Jet Velocity Link Temperature Time to Activation Results Time to Detector Activation Predicted Detector Temperatures and Gas Temperatures Appendix B: Data Used for Sensitivity Analysis References