Hi dunham,
ISODIM by Joseph E. Willis is a very good program. Where I work bought 5 licenses at $75 each 5 years ago.
It is super.
The only link I can find is: http://www.freecadapps.com/swdetails.php?page=search&value=&orgvalue=&review=5736&rowcolor=fce08d
I think version 1.1 is dimensioning and text only.
Version 2.1 has all the pipe, valves, equipment, etc.
I searched CADDEPOT.COM & CADOPOLIS.COM without success. Maybe you can find the later version.
The author is:
Joseph E. Willis
12146 Pine St.
Gramercy, LA. 70052
United States
Perhaps you could contact him directly.
bayoubuoy