A heat detector is a safety device designed to sense changes in temperature, typically used in fire alarm systems. It activates an alarm when it detects a significant rise in heat, indicating a potential fire. Heat detectors are commonly found in residential and commercial buildings, providing an essential layer of protection against fire hazards. There are two main types of heat detectors: fixed temperature and rate-of-rise. Fixed temperature detectors trigger an alarm when the temperature reaches a predetermined level, while rate-of-rise detectors respond to a rapid increase in temperature. Both types play a crucial role in fire safety, helping to alert occupants and prevent damage.