Is there a code requirement for bathroom fan CFM?

[DragonBallz]

Located in Massachusetts

I am renovating a 114 sqft bathroom. Ceiling height is 8 ft. 1 regular shower, 1 regular bathtub, 1 toilet, 1 sink

Can I get away with a 110 CFM fan on a 4” solid duct about 6’ long with 1’ of flex duct?

Will that be code?

 

[John Gayewski]

Located in Massachusetts

I am renovating a 114 sqft bathroom. Ceiling height is 8 ft. 1 regular shower, 1 regular bathtub, 1 toilet, 1 sink

Can I get away with a 110 CFM fan on a 4” solid duct about 6’ long with 1’ of flex duct?

Will that be code?

It will be based on air changes per hour if there is, but I doubt it'll be in the plumbing code. It would be in mechanical or hvac code.

 

[Sponsor]

 

[Jadnashua]

I've seen various recommendations, but about 8 changes/hour seems to be fairly common. A 110cuft/min is slightly under that. THe ultimate flow will depend on the actual fan and the functional length of the duct, which includes adjustments for elbows, etc.

Don't know if there's an actual code requirement on the size. Generally, it requires either a fan or a workable window to meet the minimum code. Safest thing is to ask at your local building inspector's office. MA has a fairly good state website that you should be able to research.