The diameter of the first section is 5 inches, the second section is 4.92 inches, the third section is 4.72 inches, and the fourth section is 4.53 inches.
The chimney has four sections in total and the dimensions of each section are as follows.
Section 1:φ127*484mm
Section 2:φ125*484mm
Section 3:φ120*484mm
Section 4:φ115*484mm
It has no bends.