1. Assessment Of Fire Suppression Capabilities Of Water Mist
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

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 The Master Thesis
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 mist generated
Water mist volumetric behaviour (situation without fire)
Re-ignition probability
Possible pressure variations in the compartment
Consequences of spraying water mist
Regarding the Fire fighters
Regarding a potential victim

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 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 Experimental protocol
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 Experimental protocol
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 1 2 3 4 6 5 7 8 9
Fire scenarios
Q = 56 L/min
Sf = 12.8 m2
Ac = m2 1 2
Ao= 2.71 m2 3
Sr = 8.4 m2 4 5
Qr = 28 L/min 6 7 8 9
Possibles fire scenarios
Water flow rate
Burning Surface
Area of the openings
Designation of the scenario

25. Methodology Scenarios Experimental protocol
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 Experimental protocol
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 Spray pattern
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. Flame tackling 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. Entire fire development, shown 40 times faster
Gas cooling phase
Entire fire development, shown 40 times faster

39. Extinguishing phase, 4 times faster
Gas cooling 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 Property 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 Property 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 temperature destratification
Scenario n°6

47. Results Safety concerns Life safety Property 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. Property safety

51. Conclusion Publication Translation in french
Haut-Rhin Fire & Rescue Services
FIREFIGHT?

52. Thank you for listening
Questions?