2. Summary of the presentation:
Gas supply in the north area
Network configuration
Accidental scenarios
Result of the risk analysis
Safety prescription
Thanks to : HSE-OHS, EP, FGSO and TE safety officers !
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3. Gas supply in the north area – ECN3 EHN2 side
908:
920:
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4. Gas supply in the north area – EHN1 side
LN2 32 m3 10 bar – Saleve side
LAr 6000 L 10 bar – Saleve side
LAr Jura Side NP platform
LN2 Jura Side NP platform
907: iC4H10, C2H2F4, CO2
909: Ar, CO2, CF4, C3F8, CO2,iC4H10,C2H2F4, SF6, H2, Ne
895: He – TE VSC
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5. 2) Configuration and layout of the network
Gas network going inside the technical galleries.
More than 1 km of pipes inside the galleries in the north area (He, N2, Ar, CO2)
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6. 2) Configuration and layout of the network
Detail of EHN1 galleries
Detail of EHN2 galleries
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7. 2) Configuration and layout of the network
Picture of the gas network inside the galleries
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8. 2) Configuration and layout of the network
Galleries volume:
3m x 2.5m - length detailed in the risk analysis depend of the area
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9. 2) Configuration and layout of the network EHN2
Access to the gallery GT806
Access to the gallery GT807
No lock, no signs, open to anyone
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10. 3) Accidental scenarios
Small leak due to corrosion on tubes, flanges, seals or valves
Temperature variation,
Water leaks,
Shock during worksite.
Human error: (already happened twice in the last 3 years)
- Bad connection,
- Tap left open,
- Untrained persons.
Additional factors : No live monitoring of the gas consumption, no ventilation in the galleries, partial fix detection, free access, no lock on the access doors, no warning signs.
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11. 3) Method of the risk analysis
𝐹𝑙𝑜𝑤=𝐶∙𝐴∙ 2∙𝛥𝑃 𝜌 𝐿 𝑚 3 𝑠
𝑡 𝑐 1 =− 𝑉 𝑅 ∙𝑙𝑛 𝑐
C = a value of 0.62 assumed for a square hole
R = leak rate (m3/h)
A = size of the hole in m2
V = free volume (m3)
C1 = final concentration ex:18%
P = difference in pressure between the gas line and the atmosphere
L the density of the leaking gas
Fermilab ES&H Manual :
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12. 3) Result of the risk analysis
Leak size N2
Time to 18% O2
CO2 Time to 19.5% (toxicity)
EHN1 Large leak
45.8 min longitudinal gallery
5.7 min transversal gallery
16 hours longitudinal gallery
2 hours transversal gallery
EHN2 Large leak
50 min GT806
15 min GHN21
14.4 minutes GT806
few seconds GHN21

13. 3) Result of the risk analysis
Probability :
1: No event during the last 5 years
3: On average 1 event/ years during the last 5 years (CO2 leak EHN1, Rupture of valve)
5: More than 5 events / years during the last 5 years
Reasonable maximum Severity :
1: Slight injury (1st degree burn, contusion…)
5: Injury with days off (broken legs, 2nd degree burn…)
10: Injury with work disability or fatality – major environmental damages
Current level of control :
1: A safety management system is continuously improving the OHS level
3: A safety management system is in place but still have to be improved
5: Non-compliant with the applicable safety rules (no detection of the hazard)
Probability x Severity x Level of control = 150 1
250
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14. 4) Prescription on going EHN1 only
Implemented in EHN1 only
IMPACT
TRAKA
ODH Portable + Key
Not yet
Implemented in EHN1 only
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15. 4) Prescription for the consolidation project
Technical solutions:
Install the ventilation system for the gas barrack certified ATEX
Priority 1
Mandatory by law
Add lock on the access doors to the galleries – add safety signs, safety consign on all the access.
Install a ventilation system in the gallery in order to avoid local accumulation of gas
Priority 2
Reduction the risk of accumulation
Installation of detector inside the galleries
Priority 3
Reduce the risk
Install an instrumentation to monitor and secure the gas consumption in the north area
Priority 4
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16. 4) Prescription for the consolidation project
Organizational solutions:
Procedure for portable ODH- CO2 detectors mandatory – lone work forbidden
Priority 1
Mandatory by law
Perform regular inspection (non-destructive testing) on the areas of piping
Check on the “blue pipes type Rilsan ” in all the areas
Reinforce the “user installation process” in collaboration between EP and EN
Priority 2
Safety improvement
Coherence between ODH risk analysis process amongst department (access, detection, procedure, signs, acceptation, risk assessment methodology…)
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17. Thanks for your attention !
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