General The Signature Series smoke detectors bring advanced sensing technology to a practical design that increases efficiency, saves installation time, cuts costs, and extends property protection capabilities. Continuous self-diagnostics ensures reliability over the long-haul, while the latest thermister technology makes these detectors ideal wherever dependable heat detection is required. The SIGA-HRD is an intelligent fixed temperature/rate-of-rise fire detector. It monitors the temperature of the surrounding air and analyzes the data from the sensor to determine whether to initiate an alarm. The rate-of-rise heat function quickly detects a fast, flaming fire. The fixed-temperature heat function detects fire when the air temperature near the detector exceeds the alarm point. The SIGA-HFD is an intelligent fixed-temperature heat detector that contains a fixed-temperature heat sensor rated at 135 °F (57.2 °C). It does not have a rate-of-rise function. The heat sensor monitors the temperature of the air in its surroundings and the detector analyzes the data to determine when the air temperature near the detector exceeds the device’s alarm point. Features  • Next Generation Heat Sensing Technology • 135 °F (57 °C) fixed temperature alarm point (HRD and HFD) • 15 °F (9 °C) per minute rate-of-rise alarm point (HRD) • Uses existing wiring • Automatic device mapping • Sensor Markings Provide Easy Testing Identification • Up To 250 Total Signature Devices Per Loop • Non-volatile memory • Electronic addressing • Bicolor (green/red) status LED • Standard, relay, fault isolator, and audible mounting bases • 50 foot (15.2 meter) spacing