Fire Dynamics Research Applied to. Fire Investigation. Overview

Transcription

1 2017 NFPA Conference & Expo Fire Dynamics Research Applied to Fire Investigations Presented by: Daniel Madrzykowski Research Engineer UL Firefighter Safety Research Institute Fire Investigation What is the problem? Interpretation of fire patterns is one of the basic methods of determining the area of origin Currently there is limited scientific literature on the development of burn patterns. much more research is needed on the natural variability of burn patterns 1 Experiments should be designed to put arson investigation on a more scientific footing Strengthening Forensic Science in the United States: A Path Forward, Committee on Identifying the Needs of the Forensic Sciences Community ; Committee on Applied Theoretical Statistics, National Research Council, National Academy of Sciences, Overview Compartment Fire Dynamics What is burning? Fuel Vs. Ventilation Limited Fires Convection vs Radiation Fire Triangle based Analysis Fire Pattern Experiments Fuel Limited Repeatability Ventilation Limited Structure Fires Application What s Next 1

2 Smoke is Fuel Heat Release Rate Comparison Cotton Synthetic 2

3 Evolving Fuel Loads 7 Evolving Fuel Loads Heat Release Rate 9 3

4 Fire Pattern Repeatability Flame Height vs. Pattern Height 0.65 m 1.0 m Madrzykowski, D. and Fleischmann, C., Fire Pattern Repeatability: A Study in Uncertainty, Journal of Testing and Evaluation, ASTM International W. Conshohocken, PA.,Vol 40, No. 1, January 2012, pp Mean Pattern Height = 0.83 m Mean Flame Heights vs Fire Pattern Heights Values presented with 95% confidence limits Fire Dynamics in a Structure Ideal Fuel Controlled Model Ideal Ventilation Controlled Model 4

5 Flow Paths The flow path is the volume between an inlet and an outlet that allows the movement of heat, smoke and air from the higher pressure areas towards the lower pressure areas accessible via doorways and window openings. Single Compartment Uni-directional Flow vents Uni-directional Intake Uni-directional Exhaust Bi-directional Flow vent A single vent serving as both an intake and exhaust vent. 5

6 Neutral Plane The interface at a vent, such as a doorway or a window opening, between the hot gas flowing out of a fire compartment and the cool air flowing into the compartment. The Impact of Ventilation on Room Fires in Full Scale Structures UL FSRI Technical Panel Robert Byrnes, FDNY, New York Steve Carmen, Carmen & Assoc., California Paul Claflin, ATF, Alabama Chris Connealy, SFM, Texas Richard Dyer, Dyer Fire Consulting, Kansas John Golder, ATF (ret.), North Carolina Mark Goodson, Goodson Engineering, Texas David Icove, University of Tennessee John Lentini, Scientific Fire Analysis, Florida Kevin McGrattan, NIST, Maryland Michael Murphy, Chicago Fire Department, Illinois James Novak, St. Paul Fire Department, Minnesota Robert Pyzyna, Northbrook Fire Department, Illinois 6

7 Impact of Ventilation Structure Fires Thermocouple Temperature Instrumentation Bi-Directional Probe Temp & Pressure Oxygen & Pressure Sensors Pressure and Oxygen Probes 20 Floor Plan 7

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9 LR1 Closed Temperature LR1 Closed Pressure 9

10 LR1 Closed Oxygen Concentration 1.2 m LR1 Closed Oxygen Concentration 0.1 m 10

11 LR2 Closed Temperature 11

12 LR2 Closed Pressure LR2 Closed Oxygen Concentration 1.2 m LR2 Closed Oxygen Concentration 0.1 m 12

13 Living Room Open Door 13

14 Living Room, Open Front Door LR3 Open Temperature 14

15 LR3 Open Pressure LR3 Open Oxygen Concentration 1.2 m LR3 Open Oxygen Concentration 0.1 m 15

16 Bedroom 1 Closed Door Bedroom 2 Open Door 16

17 LR4 Open Temperature 17

18 LR4 Open Pressure LR4 Open Oxygen Concentration 1.2 m LR4 Open Oxygen Concentration 0.1 m 18

19 Single Story Experiments Living Room All Exterior Doors & Windows Closed (2) Front Door Open (2) Kitchen All Exterior Doors & Windows Closed (2) Front Door Open (2) Bed Room 1 Both BR1 Windows Open (2) Front Door & Both BR1 Windows Open (2) Summary Fire patterns near area of origin repeatable Impact of ventilation repeatable Fire patterns within the room of origin led to area of origin when considering the impact of ventilation Fire patterns generated pre flashed persisted post flashover if the ventilation points were remote. Coming soon Multi level impact of ventilation Examination of Arc Fault Protection Validation study for FDS 19

20 Further Needs Fires with Fire Department overhaul Extended burn times Fire extension to the structure Impact of HVAC Some basics matrix of thermal degradation conditions for painted gypsum board (new and old) Impact of time and ventilation CFITrainer.net Thank you Follow us on Facebook & Twitter 20

21 2017 NFPA Conference & Expo CEUs: To receive CEUs for this session, scan your badge at the back of the room before leaving Evaluation: Complete a session evaluation on the mobile app. (Search app store for NFPA 2017 C&E. ) Handouts: Handouts will be available via the mobile app and at nfpa.org/conference Recordings: Audio recordings of all sessions will be available free of charge via NFPA Xchange. 21