Thomas Otto, Safety Officer, TE Dept.

Evacuation at Point 5 Summary of Facts 11th LSC, Thomas Otto, TE Safety Officer3 13:26One ODH alarm (level 3) triggered in CMS underground gas room. Three flashing lights. FB sends fire engine to Point 5 CMS FGSO independently alerted by personnel working underground. Goes to XCR, but cannot see the alarm on-screen 13:43FB arrives at Point 5. Reconnaissance team to underground Recon team detects no gas, but visitor’s group 13:46Telephone discussion with CMS Deputy TC. Based on the available information, evacuation of USC55 and UXC55 is decided. ULs and UJs are included in evacuation matrix SMACC collaborator in UL55 hears alarm, phones and is told that personnel in arcs who entered by Point 5 should also evacuate.

Trace of the ODH Detector 11th LSC, Thomas Otto, TE Safety Officer4 Detector close to ground, detects heavy gases. 2 nd detector close to ceiling, for light gases. No true redundancy for alerting.

Principle of the ODH system One detector triggered: Level 3 alarm, visible on CSAM screen FB sends fire engine for reconnaissance and intervention, if necessary BE-OP-TI alerts GS-ASE piquet Two adjacent detectors triggered: Automatic evacuation alarm in an area defined by the “Matrix” Here: USC55, UXC55, ULs, UJ56, UJ53 Evacuation assisted by FB 11th LSC, Thomas Otto, TE Safety Officer5

Reasons for the manual order to evacuate Three flashing lights were (falsely) interpreted as if more than one detector fired A visitor’s group in the CMS underground No alarm in the Detector Safety System, (falsely) interpreted as a potential fault. The deputy TC was far and based his acquiescence on information received by telephone only. Thanks to previous training, evacuation was extremely professional 11th LSC, Thomas Otto, TE Safety Officer6

Evacuation zone 11th LSC, Thomas Otto, TE Safety Officer7

What happened to the Arcs ? One SMACC collaborator walked from Arc56 to Arc45 and heard the alarm in UL55. He cross-checked with his colleagues in the arcs, they did not hear an alarm. He phoned and was told that everybody who entered by Point 5 should evacuate and meet at the assembly point. This message is contrary to the evacuation matrix 11th LSC, Thomas Otto, TE Safety Officer8

Conclusions Evacuation of the Experimental area until the UJs was a conservative measure justified by the limited and apparently contradicting information available. The partial evacuation of the tunnel was result of erroneous communication between workers in the tunnel and the SCR operator of the Fire Brigade. 11th LSC, Thomas Otto, TE Safety Officer9

Recommendations CMS shift crew must be able to see L3 alarms. Keep CSAM window open or integrate in DSS Improve ODH detection in CMS gas room Create true redundancy of detectors FB adapts SCR message during evacuation: Persons hearing the alarm loud & clearly evacuate FB cannot rely on the correct “head count” when evacuating an LHC underground area. An S&R patrol may be necessary 11th LSC, Thomas Otto, TE Safety Officer10

1 st LS1 Accident in LHC A worker went underground to verify vacuum bake-out controls He did not intend to touch the heating blankets, no PPE (overall, mask, safety glasses) He realised that one heating blanket had to be fixed While doing this work, glass fibre dust entered his eye Effect aggravated by contact lens Serious eye irritation, 2 days sick leave, under medical observation. 11th LSC, Thomas Otto, TE Safety Officer11 Situation similar to real accident Use prescribed PPE even for the shortest intervention in a hazard zone.

Barriers All temporary barriers must bear an identifying sign with Name Telephone number of the person or service responsible 11th LSC, Thomas Otto, TE Safety Officer12

Is your helmet up-to-date ? lifetime 5 years 10 years Annual self- check: - Appearance - Scratches, cracks, burn marks - Functional check of adjustable elements 11th LSC, Thomas Otto, TE Safety Officer13 Vintage models from LEP must be changed. Models from early LHC construction : verify production date. See:

Safety Matters ! We control risks, not people 11th LSC, Thomas Otto, TE Safety Officer14

11th LSC, Thomas Otto, TE Safety Officer 15