Subject: Re: Ductulator Curve Equations Wanted

From: [email-masked] (Michael McKenna)
Date: Fri, 20 Oct 1995 07:23:13 GMT

Michael Lum <[email-masked]> wrote:

>Has anyone noticed that the current Trane Ductulator predicts air 
>friction values that are 1% to 12% higher than values read from 
>the ASHRAE air friction curves?  Does anybody know why?  Does 
>anyone know who generated the curves used in the Ductulator?

If you read the fine print very carefully, you'll find that the
friction values in the duculator are based on the roughness of lined
or fiberglass duct and as such will always be more conservative that
the ASHRAE tables.

I've seen duculators with references to the 1956 Fundamentals, so how
old the source calculations are is anyone's guess.

But that's just my opinion, I could be wrong,
The Yello Jacket
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"Live by the foma that make you brave and kind and
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