dryer booster fan requirement lifted?

During a frame inspection today I mentioned to my client that the dryer vent pipe exceeded 25’ so a booster fan would need to be installed. The builder tells me that this requirement was lifted in the 2007 code. That is the first I had heard of it so wanted to know if I was “late to the party”.

The manufacturer of the dryer appliance will state a maximum length.

Manufacturer’s chart(example only)

I had a lady call me as one of many looking for an answer to her smelling the dryers from above her in a 3 story building.
The limit is 25 feet.
I told her she may need to have a booster fan installed and mentioned that you deduct 2.5 feet for every bend however I did not stop to check Mikes chart yet.
All I know is she had some duct company come out and claim they could not add a booster by law.
My suggestion was to look up the dryer manufacturer and see what they say about it.

Oh they are interconnected to the roof apparently.

I agree with Michael, it depends on manufacturer.

Dryer Venting Comparison Chart

The maximum length a dryer vent can be before problems arise or are noticed varies greatly between brands and models. The vent material and the type of outside vent cover being used also contribute to the maximum vent length allowed. The chart below allows for a comparison between different brands to provide some examples.


GE (6.0+ capacity electric models) Rigid Metal A 90 ft.60 ft.45 ft.35 ft.25 ft.

Thanks for that comparison chart Chris and the input from the other guys.

Why am I always the other guy.:frowning:

You know why. :cool:

heh heh,yeah I guess I do.:slight_smile:

Thanks especially to… “BOB”… for your help. :smiley:

Hey,as in am not the other guy.:mrgreen: