Refer to sheet AC30 and table C-9-B in the code. The exhaust flue (vent) will be double wall metal type “B” for the furnace and will be 20` high with no lateral offset. Based upon the furnace output, what size flue (vent) is required?

Refer to sheet AC30 and table C-9-B in the code. The exhaust flue (vent) will be double wall metal type “B” for the furnace and will be 20` high with no lateral offset. Based upon the furnace output, what size flue (vent) is required?