2024-12-21 00:00:00 Calculate the duct size from the offset . I will calculate the channel length of the spiral duct and round duct . 45 degrees from 45 degrees , 90 degrees from 45 degrees , I will calculate the size at 90 degrees from 90 degrees . Not only horizontal swing , you also calculated up and down swing . In addition to duct also , it might be used in the piping .