KEK, 04/28/061 Safety Plan Assumptions Break out of fire in the Beam Tunnel is negligible Cables in the Service Tunnel is main fire load They are combustible but do not burn with fire Smoke is the main hazard Oils are to be kept in shielded container Evacuation to underground refuge area is considered in place of evacuation to the ground surface Access shafts are provided at 5 km distance owing to a machine layout. 5 km long tunnel constitute a fire compartment Occupant in one fire compartment is assumed to be approx. 50 persons

2 Means of Egress Travel distance of direct evacuation from the Service Tunnel to the refuge area in the access hall is too long (Max. 5 km) The auxiliary tunnels connecting two tunnels will be provided at an interval of 500 m as a means of evacuation Evacuation will be made from the Service Tunnel to the Beam Tunnel through the Connecting Tunnel and to the refuge area in the access hall through Beam Tunnel The Connecting Tunnels will be in crank shape for the purpose of shielding to substitute for a heavy door Evaluation of the safety secured by this means of egress remains to be done

3 Connecting Tunnel Scheme

4 Smoke Control In case of fire, smoke in the Service Tunnel is mechanically exhausted The Connecting Tunnel, the Beam Tunnel and the refuge area are pressurized to prevent an intrusion of smoke Fire Detection and Fire Alarm Automatic fire alarm by smoke detectors Manual fire information apparatus, located in combination with fire hydrant and emergency intercom

5 Fire Suppression Sprinklers are not proposed Fire hydrants will be installed in the Service Tunnel at interval of (TBD) Portable fire extinguishers will be placed in the Service Tunnel at interval of 60 m (TBC) Evacuation Equipment Emergency lighting of 10 lux at floor level, illuminated exit leading signs and exit signs will be installed in overall underground area

6 Communication Equipment Public addressing system with speakers in overall underground space Emergency intercom connected to the emergency control center on the ground will be installed in the Service Tunnel and the refuge area Emergency Power Supply Emergency power will be supplied to the elevator, fire detection/alarm equipment, emergency lightings exit signs and smoke exhaust system

7 Safety Control Center Safety control center will be located in the administration building on the ground It will function to watch safety status in the underground facilities as well as the surface facilities by the annunciator and indicators In case of fire, it will command the evacuation and fire fighting The direct telephone line with the local fire department will be equipped in the control center

8 Safety Equipment Following equipment shall be provided Smoke control equipment Smoke exhaust system and pressurization of refuge areas Fire detection and alarm by smoke detector Fire suppression by fire hydrant & extinguisher Evacuation equipment Emergency lights and exit signs Communication equipment Public addressing system, emergency intercom Emergency power supply Safety control center equipped with direct telephone line with local fire department