More 19+ Fireplace Opening To Flue Ratio
More 19+ Fireplace Opening To Flue Ratio. For open fires the general rule is 1:8 ratios. For a square chimney where the internal flue dimensions are 10 inches by 10 inches then the cross flow is (10x10 = 100) 100 square inches. How to get the air draft going to make sure your flames and. Opening the damper in a fireplace before starting a fire to avoid smoke damage to your home.