The uppermost part of the flame is called the non-luminous or oxidising flame, while the middle and lower portions are called the luminous or reducing flame. Luminous character is due to the presence of carbon particles in the flame.
Non-luminous flame is the hottest part and used for performing flame test. Luminous part is used for performing charcoal cavity test. Highest temperature attained in a bunsen flame is about 1550°C. A sooty flame can be converted into a non-sooty flame by admitting more air, i.e. by opening the air hole.
