Generally, in the process of building a kitchen, there are many sizes of ventilation flue installation. First of all, there is an inseparable relationship according to the number of floors in the building. The ventilation flue with high floors should be larger in size, and the flue with low floors should be smaller in size. The sectional dimensions of the ventilation flue used in daily life are: 321X241 for the one below 6 floors, 341X311 for the one below 12 floors, 461X411 for the one below 24 floors, and so on.