Category iv direct venting intake and exhaust pipes pvc allowed 140 f limit furnace water heater boiler manual size of pipe and allowable lengths support terminations through wall or through roof 12 above grade or anticipated snow level in same pressure location concentric venting kit 25.
Direct vent furnace exhaust code.
When we are talking about gas furnace vent pipe code we need to talk about the different types of the vents first after all you want to keep your family safe from harm.
Colour illustration of direct vent sidewall terminal clearance distances adapted from american standard furnace installation instructions that in turn cites ansi z223 1 nfpa 54 national fuel gas code for us installations and cites csa b149 1 natural gas and propane installation code for canadian direct vent gas vent installations.
Note in direct vent installations combustion air is taken from outdoors and flue gases are discharged outdoors.
This article describes side wall vent systems for conventional mid range efficiency heating boilers furnaces water heaters we include for comparison low temperature side wall vent systems used by high efficiency or condensing boilers furnaces water heaters.
In non direct vent installations combustion air is taken from indoors and flue gases are discharged outdoors.
The different types of venting.
Direct vent chimneys or exhaust for heating appliances.
The maximum length of the exhaust duct does not include the transition duct.
Where fittings are used the maximum length of the exhaust duct shall be reduced in accordance with table m1502 4 5 1.