The steam boilers are classified according to the following conditions
1. According to the relative position of water and hot gases
a. Fire tube boiler [Cochran Boiler]
b. Water tube boiler [ Babcock –Wilcox Boiler]
2. According to the axis of shell
a. Vertical boiler [Cochran Boiler]
b. Horizontal boiler [Lancashire Boiler]
3. According to the position of boiler
a. Internally fired boiler [ all fire tube boilers] [Cochran Boilers]
b. Externally fired boiler [ all water tube boilers] [Babcock and Wilcox Boilers]
4. According to the pressure developed
a. Low pressure boiler [Pressure less than 80 bar]
b. High pressure boiler [Pressure greater than 80 bar]
5. According to the method of water circulation
a. Natural circulation [all low pressure boilers] [ Cochran Boiler]
b. Forced circulation [all high pressure boilers] [ LaMont Boiler]
6. According to the use of the boiler
a. Stationary boiler [Cochran Boiler]
b. Mobile boiler [Locomotive Boiler]
7. According to the number of drums
a. Single Drum
b. Multi Drum
8. According to the nature of
draught a. Natural Draught
b. Forced Draught
