• Welcome to The Building Code Forum

    Your premier resource for building code knowledge.

    This forum remains free to the public thanks to the generous support of our Sawhorse Members and Corporate Sponsors. Their contributions help keep this community thriving and accessible.

    Want enhanced access to expert discussions and exclusive features? Learn more about the benefits here.

    Ready to upgrade? Log in and upgrade now.

Exhaust Fan Testing

Very good explanation of why so many bath fan installs don't seem to move much air. He gives a very good explanation of the fan curve and how it affects airflow. The fans that make the most noise are the ones that are usually worst at moving air. They're cheaper and have a poor fan curve. Two different fans with the same airflow rating can move very different amounts of air, depending on the fan curve and the attached duct. Flex duct is always more restrictive to airflow than rigid duct, even when installed properly. The non-smooth interior, particularly the wire spiral, causes turbulence.
 
I read an installation manual for a bathroom fan it said not to have a bend within a certain distance from the fan, I forgot how far.
If they have a U-turn right at the fan I have them turn the fan.
 
You must log in or register to reply here.
Back
Top