Consolidation of Fire Detection System for LHC, including Sniffer

The LHC automatic fire detection system covers mainly shafts, caverns and underground services areas. LHC experiments are also equipped with a dedicated combined air-sampling fire and gas detection system (SNIFFER). Today, after 15 years of operation, these systems are reaching their end-of-life. Replacement of some aged critical components is necessary. Moreover, some constituents are no longer available on the market and the lack of spare parts could lead to important systems unavailability. In addition, new cabling is necessary in some cases since degradation from radiation may be present and to comply to the standards in force. This paper describes the design choices and proposed solutions to address the above safety concerns and to extend the life of the LHC underground and SNIFFER fire detection systems. Modern control systems and equipment will enhance systems reliability, availability, and technical data transmission, leading to optimized maintenance programs and costs. Moreover, Fire Brigade diagnostics will be eased by new displays on the LHC surface showing new parameters, such as, the level of smoke opacity.