Assessment Of Fire Suppression Capabilities Of Water Mist

1. Pg. Dip. Msc. Fire Safety Engineering Academic year 2009/2010 Assessment Of Fire Suppression Capabilities Of Water Mist -Fighting Compartment Fires with the Cutting Extinguisher- FIREFIGHT II Mid-term Meeting Wednesday 24 – Friday 26 November 2010 in Prague Julien GSELL juliengsell@orange.fr

2. Contents • Introduction • Msc Fire Safety Engineering • The Master Thesis • Why on the Cutting Extinguisher?

3. Contents • Introduction • Background • Literature review • A Thesis to answer what? • Going further in the study

4. Contents • Introduction • Background • Experimental framework • Enclosure & type of fuel • Instrumentation • Methodology

5. Contents • Introduction • Background • Experimental framework • Results • Water mist behaviour • Fire suppression capabilities • Safety concerns

6. Contents • Introduction • Background • Experimental framework • Results • Conclusion • Publication • Translation in French • Haut-Rhin Fire Service

7. Introduction • Msc Fire Safety Engineering • University of Ulster at Jordanstown Belfast, Northern Ireland • The Master Thesis • Assessment of the Fire Suppression Capabilities of Water Mist • Why on the Cutting Extinguisher? • Previous placement • Study of the manufacturing, use, and development of the tool

8. Background • Literature review • The Cutting Extinguisher - Concept and Development: Swedish Rescue Services Agency, 1999 • Holmstedt, Göran. An assessment of the Cutting Extinguisher's Capabilities and limitations: Lund University, 1999 • Winkler, Thomas Karlsen & Henrik. Skärsläckaren som röjnings och släckverktyg för fartyg av kolfiberkomposit, 2000 • Olsson, Johannes Bjerregaard & Daniel. Skärsläckaren-experimentella försök och beräkningar, 2007 • Cutting Extinguishing concept-practical and operational use: Swedish Rescue Services Agency, 2010.

9. Background • A Thesis to answer what? • How this scenario with a focused jet of water and high flow rate, where the beam is broken up into small droplets, affects the mixing of the fire gases has not so far as known been investigated • the impact of the ventilation openings on the cutting extinguishers ability to extinguish fires • the functioning of the cutting extinguisher in a well controlled fire in relation to various types of and ventilation • the importance for the efficiency of the cutting extinguisher of the water jet being able to break up • Cutting Extinguishing concept-practical and operational use: Swedish Rescue Services Agency, 2010.

10. Background • Going further in the study • Calibration of the water mistgenerated • Water mistvolumetricbehaviour (situation withoutfire) • Re-ignition probability • Possible pressure variations in the compartment • Consequences of spraying water mist • Regarding the Firefighters • Regarding a potentialvictim

11. Experimental framework • Enclosure & type of fuel • Characteristics & dimensions of the compartment • 40 feet sea container • Fire area on the bottom • 2.71 m2 openings area to be used • Type, properties & arrangement

12. Characteristics & dimensions of the compartment

13. Experimental framework • Structure & type of fuel • Characteristics & dimensions of the compartment • Type, properties & arrangement • Chipboard panels • 12.8 or 8.4 m2 burning surface • Ceiling, lateral and bottom walls

14. Type, properties & arrangement

15. Experimental framework • Instrumentation • Bottle frame • Every 0.5 m from 2.0 to 10.0 m • 144 bottles for a control surface of 324 cm2 • Thermocouple meshing • Radiometer • Pressure record • Video record

16. Bottle frame

17. Experimental framework • Instrumentation • Bottle frame • Thermocouple meshing • 99 TC distributed over 8.8 m length, 2.4 m width and 2.4 m height • Control volume of 0.512 m3 • Radiometer • Pressure record • 2 transducers • Video record

18. Temperature, pressure & heat flux

19. Experimental framework • Instrumentation • Bottle frame • Thermocouple meshing • Radiometer • Pressure record • Video record

20. Video record

21. Methodology • Scenarios • Location of the Cutting Extinguisher • Front wall, mid-length, 1.65 m high • Studied parameter • Experimental protocol • Exploit of the “Bottle frame” • Full scale burnings

22. Location of the Cutting Extinguisher

23. Methodology • Scenarios • Location of the Cutting Extinguisher • Studied parameters • Volumetric distribution of water • Influence of opening area, fuel surface, and water flow rate • Experimental protocol • Exploit of the “Bottle frame” • Full scale burnings

24. Studied parameters • Fire experiments

25. Methodology • Scenarios • Location of the Cutting Extinguisher • Studied parameters • Experimental protocol • Exploit of the “Bottle frame” • Full scale burnings

26. Exploit of the bottle frame

27. Methodology • Scenarios • Location of the Cutting Extinguisher • Studied parameters • Experimental protocol • Exploit of the “Bottle frame” • Full scale burnings

28. Full scale burnings

29. Results • Water mist behaviour • Total flooding • Water content: 44 g/m3 • Volumetric flow rate: 21.2 m3/s • Velocity: 7.13 m/s • Spray pattern

30. Total flooding

31. Total flooding

32. Results • Water mist behaviour • Total flooding • Spray pattern • Inner core + outer ring • Initial diameter: 4.5 ° • Break up point at 5.0 m • Widening following an angle of 9.0 ° • Application modes

33. Spray pattern

34. Results • Water mist behaviour • Total flooding • Spray pattern • Application modes • Spread droplets into the flames • Spread droplets in the smoke layer • Inerting by steam generation • Cool the burning fuel surface • Shield the fuel surfaces not yet involved

35. Results • Fire suppression capabilities • Flame tackling time • Fire extinguished every time • Below 15 seconds regardless to the scenarios • Major effect trough blowing and heat extraction • Influence of parameters during gas cooling phase • Re-ignition probability

36. Flametackling time

37. Results • Fire suppression capabilities • Flame tackling time • Influence of parameters during gas cooling phase • Initial “plateau” • Reducing fuel surface: faster to reach safe level • Increasing opening size: faster to reach safe level • Reducing water flow rate: cooling down more difficult • Re-ignition probability

38. Gascooling phase Entire fire development, shown 40 times faster

39. Gascooling phase Extinguishing phase, 4 times faster

40. Results • Fire suppression capabilities • Flame tackling time • Influence of parameters during gas cooling phase • Re-ignition probability • Likely to occur • No significant temperature or fire rise within 3 min • Limited action of surface cooling • Requires to wet the remaining charring material

41. Re-ignition probability

42. Results • Safety concerns • Life safety • Radiation shielding • Remaining of the “oxygen survival layer” • No high temperature or smoke feed back • Property safety

43. Life safety • Radiation shielding

44. Radiation shielding Spraying period

45. Results • Safety concerns • Life safety • Radiation shielding • Remaining of the “oxygen survival layer” • Also mixing & temperature destratification • No high temperature or smoke feed back • Property safety

46. Mixing and temperaturedestratification Scenario n°6

47. Results • Safety concerns • Life safety • Radiation shielding • Remaining of the “oxygen survival layer” • No high temperature or smoke feed back • Property safety

48. Life safety

49. Results • Safety concerns • Life safety • Property safety • No water damage • No over pressure

50. Propertysafety