Power plants, such as hydroelectric, nuclear or gas-fired power plants, transformer stations within the power distribution grid, as well as utilities, such as water treatment facilities, urban service tunnels and recycling plants, are considered to be critical infrastructure of cities, states and countries. As fires are a root cause for service interruptions in such facilities, operators cannot risk compromising their service level through an undetected fire. In fact, an Early Warning Fire Detection System, supporting multiple alarm thresholds, ensures operators that fires are detected as early as possible and reacted upon in an adequate and timely manner in order to ensure business continuity and minimal damage to infrastructure.