Excel Fire Modeling and CFAST Integration_Handout
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Rob Plonski presented on integrating Excel fire modeling with the zone fire model CFAST. The Excel model allows for rapid development of varying heat release rate profiles and flashover analyses. It produces an input file for CFAST, adding a user interface. The integration enables fast comparison of scenarios and sensitivity analysis. Future work includes improving the heat release rate database and simulation time, integrating with CFAST V6, and adding Monte Carlo analysis. The goal is to provide a simple yet capable fire modeling tool.
Excel Fire Modeling and CFAST Integration_Handout
- 1. Excel Fire Modeling and CFAST Integration 2015 DOE Fire Safety Workshop May 5-7, Alexis Park Hotel 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 1
- 2. Agenda Introduction Why Excel? Capabilities How It Works Limitations Looking Forward 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 2
- 3. About Me (2009-2015) Undergrad in Mechanical Engineering Masters in Fire Protection Engineering (Current) Rob Plonski PE in NM Fire Protection Engineer Fire Protection Engineer 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 3
- 4. Excel Fire Modeling (Why?) Why do I want to use Excel? ◦ Fast ◦ Simple (equations/correlations) ◦ Reliable ◦ Easy to use ◦ Easy to explain ◦ Easy to distribute 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 4 NUREG 1805: Quantitative Fire Hazard Analysis Methods for the U.S. Nuclear Regulatory Commission Fire Protection Inspection Program 22 separate tools (Fire Dynamics Tools) Ways to Model Fire Hand Calculations Zone Models Field Models • Predicting HGL, Flame Height, Burning Duration, etc.
- 5. Excel Fire Modeling (The Model) 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 5
- 6. Excel Fire Modeling (Composition) Modular Construction • HRR Database • Cumulative HRR Development • Flashover Correlations • Sprinkler/Heat Detector Activation Time • Simulation History • Development of CFAST Input File 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 6
- 7. Excel Fire Modeling (Capabilities) HRR Database 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 7 ** Times MUST be input evenly divisible by 25 and hrr should either terminate or have a 1000s timestep Name T1 HRR1 T2 HRR2 T3 HRR3 T4 HRR4 T5 HRR5 Desk 200 50 300 400 400 650 600 150 1000 300 Computer 200 35.53333 300 65.8 450 225.7 500 195.6667 600 131 Chair 100 225 250 152 500 100 1000 80 Trashbag 50 175 75 244.5 125 348 175 340 225 280
- 8. Excel Fire Modeling (Capabilities) Cumulative HRR Development 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 8
- 9. Excel Fire Modeling (Capabilities) Flashover Correlations 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 9
- 10. Excel Fire Modeling (Capabilities) Sprinkler/Heat Detector Activation Time 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 10
- 11. Excel Fire Modeling (Capabilities) Simulation History 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 11
- 12. Excel Fire Modeling (Applications) 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 12 Development of CFAST Input File
- 13. Excel Fire Modeling (How it works) Cumulative HRR Development Model identified in Enclosure Fire Dynamics by Karlsson & Quintere 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 13
- 14. Excel Fire Modeling (How it works) 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 14 Flashover Correlations
- 15. Excel Fire Modeling (How it works) Sprinkler/Heat Detector Activation Time 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 15
- 16. Excel Fire Modeling (How it works) Sprinkler/Heat Detector Activation Time 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 16
- 17. Excel Fire Modeling (How it works) Development of CFAST Input File 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 17
- 18. Excel Fire Modeling (Limitations) HRR Database 25-Second intervals Maximum of 1000 seconds Linear interpolation in-between points Cumulative HRR Development 25-Second intervals Maximum of 1000 seconds Linear interpolation in-between points Each combustible-type ignites at time=0 Next combustible of same type ignites at next time interval (25s, 50s, 75s, etc.) 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 18
- 19. Excel Fire Modeling (Limitations) Flashover Correlations Babrauskas (ΔT=600°C ) Based on energy balance of McCaffrey, Quintiere, & Harckleroad Mass outflow proportional to the size of the doorway opening Based on a limited number of experimental test data Assumed primary energy loss to be radiative to 40% wall area at ambient temperature Based on a best fit of a stoichiometric heat release rate for doorway opening McCaffrey, Quintiere, & Harckleroad (ΔT=500°C ) Thomas (ΔT=600°C) Cubic-shaped rooms 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 19
- 20. Excel Fire Modeling (Limitations) 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 20 Sprinkler/Heat Detector Activation Time Quasi-Steady-State Falls apart when HRR declines Can produce an unrealistic reduction in temperature Simulation History Maximum of 1000 seconds Difficulty in accounting for changes in HRR database Development of CFAST Input File One doorway No corridor 21 datapoints (HRR timesteps) Predefined construction types
- 21. Excel/CFAST Integration (Capabilities) Cumulative HRR Model Rapid development of varying HRR models Rapid comparison of varied scenarios (total energy released) Rapid development of a HRR profile and verification of correct input Rapid screening of potential flashover rooms Rapid comparison of different flashover correlations Easy identification of separation distance required to preclude radiative ignition Simple identification of anticipated heat detector of sprinkler activation time 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 21
- 22. Excel/CFAST Integration (Capabilities) Excel/CFAST Integration Rapid CFAST input file development Adds a user interface to CFAST V3/5 Allows for rapid changes to CFAST input parameters Simple comparison to hand calculations 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 22
- 23. Excel/CFAST Integration (Looking Forward) How can this be improved? Get it out for feedback! HRR database with timesteps < 25-Seconds Simulation runtime greater than 1000-Seconds Integration with CFAST V6 Application of a Monte Carlo Simulation Determine other Flashover correlations Analyze model sensitivities Post-processing of CFAST output files 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 23
- 24. Excel/CFAST Integration (Recap) Why Excel? Capabilities How It Works Limitations Looking Forward 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 24
- 25. Questions? 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 25 Topic: Excel Fire Modeling and CFAST Integration Presenter: Rob Plonski Contact: RobPlonski@YourFPE.com
- 26. Excel/CFAST Integration (Link) Model Here 2015 DOE NUCLEAR AND FACILITY SAFETY WORKSHOP FIRE SAFETY TRACK EXCEL FIRE MODELING AND CFAST INTEGRATION 26