There are 2 kinds of kitchen duct size: 1. The standard of kitchen flue size is: 300*300 Kitchen flue hit out can be the hood's exhaust pipe from the kitchen ceiling through the balcony, and then connected to the outside of the balcony to go. 2. Its size ventilation duct and flue that mouth is 160mm. generally use PE or PPR pipe, the diameter of the pipe is 20mm, the downstream water for the two way, the waste water pipe pvc50mm, Waste water pipe pvc110;