explain the concept of explosion suppression basic concept of explosion explosion classification properties of ecaro25 advantages of ecaro25

2.  A quantity of fire extinguishing agent is
delivered that suppress the explosion at the
point of impact.
 The fire extinguishing agent attacks the
emerging flames, rendering the atmosphere
incapable of supporting the explosion.

3.  An explosion requires four elements :
 (1) Fuel
 (2) Oxygen
 (3) An ignition source
 (4) A confined space

4.  Fuel
 Can come from a bulk material that produces dust
clouds, a flammable gas or a volatile chemical that
creates vapour.
 Oxygen
 Available with atmosphere presence.

5.  Source of ignition
 Fire
 Flame
 Hot surface like welding arc
 Frictional sparks
 Electrostatic
 Spontaneous combustion (auto-ignition)

6.  Confined Space
 Enclosed volumes
 Explosive storage room
 Industrial processing plant
 Flammable liquid mixing or blending room
 Chemical plant.

7. Once all the
four elements are
together, the
potential for an
explosion exists.

8.  2 types : Deflagration and Detonation
 The difference depends on the speed of the
shock wave originating from the explosion.

9.  Suppose a combustible mixture is placed
within a long pipe.
 A small spark or ignition source initiates the
reaction at the end of the pipe.
Reaction Zone:
- Energy released
- Chemical mole change
Pressure of Shock Wave
- Un-burnt Gases Compressed
and heated.
---------------------------------------------------------------------------
Reacted Gases Direction of Propagation Un-reacted Gases

10.  After ignition, a flame and reaction move
towards the other end.
 A pressure shock wave created in front of the
flame.
Reaction Zone:
- Energy released
- Chemical mole change
Pressure of Shock Wave
- Un-burnt Gases Compressed
and heated.
---------------------------------------------------------------------------
Reacted Gases Direction of Propagation Un-reacted Gases

11.  The pressure shock wave is due to the
expansion of gases by the reactions either
stoichiometric effect (change in the number
of chemical moles) or thermal expansion
effect.
Reaction Zone:
- Energy released
- Chemical mole change
Pressure of Shock Wave
- Un-burnt Gases Compressed
and heated.
---------------------------------------------------------------------------
Reacted Gases Direction of Propagation Un-reacted Gases

12.  If the pressure wave moves slower than the
speed of sound.
 The explosion is DEFLAGRATION.
 If the pressure wave moves faster than the
speed of sound in the reacted medium
 The explosion is DETONATION.

13.  For deflagration, the pressure increase is
typical several atmospheres.
 For detonation, the pressure increase rise is
typical ten times higher or much more.

14.  Deflagration typically a relatively slow flame
and pressure front movement.
 Detonation where energy must be released in
a very short time within a very small volume
to produce a significant initial pressure or
shock wave.

15.  In brief term, an explosion is a freely
propagating combustion wave.
 2 mechanisms are involved :
 Thermal mechanism
▪ The gas temperature increase by reaction, leading to
self-acceleration of the reaction rate.
 Chemical chain branching mechanism
▪ Reactive free radicals are rapidly occurs where one free
radical participates in a chain reaction, then later
produces 2 free radicals, 4, 8…. & so on.

16. 1. Combustion (initiated by a
flame or ignition source)
2. Deflagration
3. Detonation

17.  When the four elements come together, an
explosion happens :
 (1) Fuel
 (2) Oxygen
 (3) An ignition source
 (4) A confined space
 The concept of Explosion suppression is to eliminate
detected ignition and fire immediately, allowing no
chance for fire to survive in minimum seconds of
time period.

18.  ECARO-25 suppression agent (DuPont FE-25) works
in 2 ways.
 (1) Thermally
▪ ECARO-25’ FE-25 agent is able to absorb heat faster than the
amount of heat generated by the combustion reaction essentially
stops the flame propagation since it can not sustain itself.
 (2) Chemically
▪ ECARO-25’s FE-25 agent forming free radicals, which chemically
interfere with the chain reaction of the combustion process. Free
radical generated from FE-25 will eliminate the reactive radicals
generated from explosion elementary reaction.

19.  The purpose of the ECARO-25 system is to
protect the room (keeping ammunitions,
explosive finished products, highly
flammable materials) from catching fire and
heating up the explosive containers.

20. HFC-227ea
CF3CHFCF3
170.0
-16.5º C
66 psi
Halon 1301
CF3Br
148.9
-57.7º C
234 psi
Property
Chemical Formula
Molecular Weight
Boiling Point
Vapor Pressure
ECARO-25
CHF2CF3
120.02
-48.3º C
200 psi

21.  Molecular Weight
 ECARO-25 is 40% lighter than HFC-227ea
 Vapor density is lesser
 Give over 20% longer holding time
 Provide longer and better inerting benefits
 Provide protection should a re-flash or re-ignition
occur

22.  Boiling Point
 ECARO-25 is 3 times lower boiling point than
HFC-227ea. (-48 ºC vs -16 ºC)
 Give wider working temperature margin
▪ High altitude by fighter jet
▪ Cold climate
▪ Special refrigerated low temp storage
 HFC-227ea is inability to provide protection under
temperature lower than -16 ºC

23.  Vapor Pressure
 Vapor pressure of ECARO-25 is 300% higher than HFC-
227ea. (200 psi vs 66 psi)
 Give easy flow as Halon 1301
▪ Longer distance flow than HFC-227ea
▪ Faster flow speed
▪ Flexibility in system design
 NFPA 2001 -> discharge time should not exceed 10
seconds for both ECARO-25 & HFC-227ea
▪ ECARO-25 could achieve 6 seconds easier than HFC-227ea for the
same quantity of agent used

24.  Extensive research
by US Department of
Defense (DoD)
 Preferred fire
extinguishing agent
by DoD
 Proven use track
record over 10 years

25. End of Presentation
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