Nat Max

The Nat Max column in the tables lists the maximum input capacity, in Btu/hour, of one draft hood gas appliance connected directly a vent or to a vent connector. Example: the maximum Btu/ hour input capacity of a draft hood water heater connected to a 3 inches diameter Type B vent connector with a vent height of 10 feet and a lateral length of 5 feet is 40,000 Btu/hour. See Table G2428.2-1.