These detectors, used primarily by large commercial or industrial firms, sound only when the temperature rises to a certain level They are not nearly as safe as the ionization and photoelectric types in that the fire must be more intense before the thermal unit will sound
Thermal clothes are specially designed to keep you warm in cold weather. My feet were like blocks of ice despite the thermal socks Thermals are thermal clothes. Have you got your thermals on?
parcel of relatively warm air that rises in an environment of cooler air (Convection)