cfm

[cdrtwn5]

HOW MANY CFM FLEX DUCT WILL CARRY 4" THRU 20"

I KNOW 6"FLEX IS ABOUT 100
AND I THINK 7" IS ABOUT 150

[Toolpusher]

I show a 6" flex being less then 85 cfm, a 7" @ 120 cfm.

I'm not going to list from 4" to 20"

They make charts and tools for that.
My listings were for .10 static

Thats why if your not sure what your doing you can really mess up an install.

A 6" flex is not a 6" metal, and shouldn't be thought of or sized as one.

[Edited by Toolpusher on 06-22-2005 at 03:26 PM]

[Senior Tech]

Try writing your question another way....honestly it makes no since at all to me....

[dan sw fl]

OHaH, about 700 F P M

[docholiday]

Agree with Toolpusher and others. Get a flex calculator and then realize that it is only accurate with the flex pulled tight and straight. IMHO in most applications 85 CFM for a 6" Flex is on the high side of reality.

I suggest looking for rules of thumb be eliminated from your list of things to do.

[dash]

The ductolator for flex or metal ,shows what the cfms will be at a "selected" Friction Rate(FR is static per 100 equivalent feet of duct),so without knowing the FR of the duct system,it's really useless.

Order Manual D for ACCA,along with J and S,and never have a duct or sizing problem with your installs again,plus fix all the bad ones you will find.

[dan sw fl]

Duct ulator is only ~ 1/3 of the total dP concern.

The MAJORITY of pressure losses are in the
fittings: elbows, transitions, tees, junction boxes, entry, exit, ...

I guess I need to
Invent the FitUlator
for obtaining the toal System Losses.