Replies

1. 
   Dave45 | Oct 15, 2007 05:34pm | #1

   Although I'm sure they exist, I've never seen any equivalent length tables for air systems.  You might find something if you do a search for "Air Handling Systems" or "HVAC Duct Design".

   Have you tried talking to the manufacturer of your dust collector?  Some of them will help you design your system - or design it for you.

   The only other advice I can give you is to:

   • Minimize the amount of flexible ducting in your system.  The corregations create turbulence which seriously reduces air flow.
   • Minimize the use of hard 90's and tees.  Long radius sweeps work much better.
   • Seal up the connections in your system.  My DC piping is mostly 4" HVAC duct with a couple of sheet metal screws at the joints.  It was pretty anemic when I first made it, but wrapping the joints with electrical tape (including the seam in the straight runs) made a huge improvement.

   Good Luck.

2. 
   QCInspector | Oct 15, 2007 09:36pm | #2

   http://www.airhand.com/designing.asp#TOP

   http://www.freecalc.com/ductloss.htm

   http://billpentz.com/woodworking/cyclone/Ducting.cfm#Ducting%20Introduction

   Check past issues of Fine Woodworking (some had the tables) and the book
   Woodshop Dust Control, 2nd Ed. Sandor Nagyszalanczy.

   http://store.taunton.com/onlinestore/catalog/Workshop

   Psst...Some of the competing magazines and books also had those tables. ;-)