AskCodeMan

Jerry,
i'm trying to get some info on whole house fans in NEC IRC, CRC...cant locate anything. Are they listed as something else?

Marc,

The only thing I can think of right now is in the IRC where, under exhausts and exhaust fans not being allowed to discharge into the attic, except for whole house ventilating fans - they are allowed to discharge into the attic space.

The energy code section probably also has something about whole house fans too,

What were you trying to find about them?

I'm just being curious. I wanted to see what the codes were specifically to their installation. I know the AHJ may fall back on manufactures specs etc... but I thought there may have been something more specific to look at. E.g., wiring, circuit, CFM per sq ft limitations, how it effects combustion and appliances with and without mechanical draft etc...

Marc,

Those aspects of the whole house fan fall back to the general code requirements applicable for the aspect in question, i.e.,:
- The wiring and circuit falls back to the NEC regarding motor wiring, circuits, and overcurrent protection, such as 422 Appliances, which in 422.3 states "The requirements of Article 430 shall apply to the installation of motor-operated appliances.
- The ventilation and fresh air return falls back to IRC Section 403 Mechanical Ventilation, which in 403.1 states "The amount of supply air shall be approximately equal to the amount of return and exhaust air. The system shall not be prohibited from producing negative or positive pressure."
- Combustion air is addressed in IRC Section 701 Combustion Air, which states in 701.2 "Every room or space containing fuel-burning appliances shall be provided with combustion and dilution air as required by this code." and "Combustion air requirements shall be determined based on the simultaneous operation of all fuel-burning appliances drawing combustion and dilution air from the room or space.", and 701.3 states "The equipment and appliances within every room containing fuel-burning appliances shall be installed so as to allow free circulation of air. Provisions shall be made to allow for the simultaneous operation of mechanical exhaust systems, fireplaces or other equipment and appliances operating in the same room or space from which combustion and dilution air is being drawn. Such provisions shall prevent the operation of such appliances, equipment and systems from affecting the supply of combustion and dilution air."

701.3 covers combustion air quite well when there is a whole house fan installed: "Such provisions shall prevent the operation of such appliances, equipment and systems from affecting the supply of combustion and dilution air."

I guess I was looking for a "catch all" code reference. But I figured I'd have to combine multiple sources to get what I was looking for.
Thanks for the time, again.
Marc