1. ALARA Committee of 14th May 2012
IMPACT ON FIRE PROTECTION AND SMOKE EXTRACTION OF PRESENT AND FUTURE PS VENTILATION SYSTEMS
ALARA Committee of 14th May 2012
14th May 2012
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2. CONTENTS Impact of a fire in a physics facility
Efficacy of present and future smoke extraction configuration
Other Fire risk reduction measures (last talk in agenda)

3. 1-IMPACT of a fire in a physics facility
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4. Risk=Probability· Consequences
The probability of a fire in PS is no more than that for a normal electric facility;
The consequences would be very severe, as a fire there could become a crisis for the Organization
Criticality of PS for CERN physics program
(SPS offline-BA3 fire in 1997, CTF3 offline in 2010);
Danger of causing chemical and maybe radiological pollution
(in the infrastructure, nearby buildings, and environment);
Complexity of cleanup and restore in a RP controlled area
Mediatic erosion of image
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5. Damage due to fire
Damage of fire to equipment is minimally due to heat;
most of the damage is made by soot and vapors contained in the smoke.
In polyethylene and rubber fires
a large percentage of the burning mass
(~20%) spreads as soot in the smoke
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6. Extensive smoke damage to most of the the facility
CTF3 fire - 4 March 2010
Cost 2.4 MCHF
4 Months stoppage
only less than half of useful beam time in 2010
Cost /m2 = ~5000CHF/m2
Extensive smoke damage
to most of the the facility
Small fire
within one
cabinet
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7. Risk reduction strategy
It is important, here more than elsewhere, to minimize probability of a fire, control its evolution, mitigate its consequence.
Keywords:
Smoke Dynamic Confinement (Smoke Extraction)
Materials (cables & IS41)
Static confinement (Compartments)
Early fire detection
Preplanned fire-fight
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8. 2-smoke extraction: efficacy of present and future configuration.

9. Role of smoke control (smoke extraction)
Loss of control of the smoke happens much more often than loss of control of the fire
Bad smoke management = damage
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10. Criteria of success for smoke extraction in PS machine tunnel
Goal: to avoid smoke spreading inside and leaks to nearby buildings
To prevent damage, most of the smoke (let’s say ~90%) should be extracted by the first two extraction points
this would confine damage within 2 stations, located at~75 meters)
Smoke Extraction Stations
90%
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11. Efficacy assessment
Machine tunnel: long geometry, efficacy of smoke extraction at distance from fire is hard to quantify without modeling ;
Comp. Fluid Dynamic has been used for:
comparing new smoke extraction vs. present situation;
assessing aspects like :
smoke propagation velocity in the tunnel
thermal impact on structures at distance from fire
Pressure differentials.
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12. basing on real scale tests of some degree of uncertainty
Modelization of fire
Fire growth cannot be calculated, this is a choice imposed to the CFD model.
This is the most delicate part of the whole assessment (and in a tunnel this is very complicated because of absence of clear limits).
We have to decide
the most likely values,
basing on real scale tests
and acceptance
of some degree of uncertainty I I I I I I
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13. Electric cabinet fires- laboratory tests
(Source: AREVA-IRSN PICSEL_A. European Reaserch Program on Electric Cabinet Fires in Nuclear Facilities )
40 kg of combustibles
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14. Heat Release Rate curves found in AREVA-IRSN test campaign on racks
1000kW
50kW
--- = HRR curve chosen to
verify smoke extraction
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15. Other fire size references (from another source).
Item
Heat Release Rate
A burning cigarette
5 W
A typical light bulb
60 W
A burning candle
80 W
A human being at normal exertion
100 W
A burning wastepaper basket
100 kW
A burning Electrical Cabinet Filled with IEEE-383 Unqualified Cables
(Vertical doors closed, vent grills only)
185 kW
A burning Electrical Cabinet Filled with IEEE-383 Unqualified Cables (Vertical doors open)
1.0 MW
A burning 1 m2 pool of gasoline
2.5 MW
Burning wood pallets, stacked to a height of 3 m
7 MW
Burning passenger car
5-10 MW
Burning polystyrene jars, in 2 m2 cartons 4.9 m high
30–40 MW
Lorry Heavy good vehicle
30-150MW
Output from a typical reactor at an NPP
3,250–3,411 MW
(Source: NUREG-United States Nuclear Regulatory commission-Series Reports- fire risk assessment in nuclear facilities-chapters 1-2)
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16. 2) 1) CFD Models Two type of models have been produced:
1) full circumference ring, to visualize propagation
2) rectified portions of machine tunnel, to evaluate efficacy 2) 1)
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17. 1) Full model
Next slides (video) show results of full model of PS ring:
Conditions:
1MW fire lasting for seconds (~16’)
located anywhere in the ring (between section 5 and 6)
Smoke extraction = 6x12000 m3/h switched on
Normal ventilation shut down
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18. 1MW fire –Existing configuration (smoke extr.=6x12000m3/h)
The two CV stations closest to fire
fire origin
Olive color lines=Smoke extraction location
PS side walls
Timeline [s]
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19. Video1 full PS ring, 1MW smoke-old configuration
Video2 full Ps ring, 1MW temperatures, old-configuration
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20. 1MW fire –Existing configuration (smoke extr.=6x12000m3/h)
16’
After 15 minutes of a 1 MW fire, most of the ring (and of the radial tunnels –not shown here) are filled with smoke
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21. T in the range of 150°C, for a 1MW fire
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22. Conclusion Fast propagation of smoke in almost the whole ring
Temperatures remain low
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23. SEE template for presentations
2) Comparison of the smoke extractions (new vs. old)
(*) All things equal, only smoke extraction power is changed between runs
1MW fire
Sm.Extr.
(*) m3/h
Side wall
Sm.Extr.
(*) m3/h
ceiling
75 meters octant
EDMS No
SEE template for presentations

24. Boundary conditions table Existing Proposed Fire size 1 MW
Normal ventilation
Shut down
Extraction
[m3/h]
Active
2x12000
2x30000
Success criteria
90% extracted
Tunnel length simulated
100m of machine tunnel, to include two nearby CV stations (circumference rectified)
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25. SEE template for presentations
1MW fire –Existing config. (smoke extr.=(6x12000m3/h)
EDMS No
SEE template for presentations

26. SEE template for presentations
Video3 –1MW-smoke –rectified-old 2 x 12000
Video4-1MW-pressure-rectified-old 2x12000
EDMS No
SEE template for presentations

27. Soot extracted by sm.ext. SEE template for presentations
Efficacy of the existing system (12000m3/h x 6) for 1MW fire
Soot produced by fire
Soot extracted by sm.ext.
3E-03Kg/s
6.6E-03Kg/s
Efficacy ~40%
EDMS No
SEE template for presentations

28. SEE template for presentations
Video5-new-smoke-2x30000
EDMS No
SEE template for presentations

29. SEE template for presentations
1MW fire –New configuration (smoke extr.=(6[8]x30000m3/h)
Most of the smoke
is extracted
EDMS No
SEE template for presentations

30. Efficacy of the new system (30000m3/h x 6[8]) for 1MW fire
Soot produced by fire
Soot extracted by CV
Very good: smoke extraction ratio
around 90%
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31. Effect of width and position of extractor
Ceiling of tunnel:
6.2E-3 kg/s
~200% increase of efficacy
Wall side of CV cubicle
3.4E-3kg/s
(Feasibility still under discussion)
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32. Efficacy on a larger fire (2.5MW-30000m3/h)
Efficacy=1.3/1.6 ~=80% still relatively good
Soot generated =1.6E-02 kg/s
Soot extracted= 1.3E-02 kg/s
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33. Verification with a different approach
New
(2x30000m3/h=16.6m3/s)
Eff=~100%
Eff=40-50%
DATE
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34. Conclusion Full support to increase of extraction rate 30000 m3/h
Activation matrix draft to be validated
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35. Ventilation control matrix in case of fire
INPUT
Equipment
Ventilation
Smoke extraction
Automatic detection of a fire
stop
(option still open)
Manual command by FB from one external switchbox on safe location
Start/ stop
Individual command for each extractor
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36. Thank you!
Questions?
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