# "Spiral" vent tubes



## Gijoe985 (Sep 25, 2012)

Hey all,

Wood shop teacher here. Questions about dust collection. I only know the basics on this topic. The maintenance guys want to put in a few new vents for me. The current 4" pipes we run are of a spiraled piping. They asked me if it _needed _to be that was, or if plain 4" ducting would work. I told them I didn't know. 

Any ideas?


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## Dave Paine (May 30, 2012)

Spiral pipe is more often seen in larger diameters.

Straight 4in duct will work as well. Normally spiral is chosen as being less expensive to fabricate. 4in straight duct is commonly available.

If the runs have elbows, try to get large radius 90's or use 2 45's to minimize pressure drop.


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## thegrgyle (Jan 11, 2011)

The spiral pipe also is air tight, whereas the snaploc ductwork is not. The spiral is also a heavier wall as well. If your entire system was run with the snaploc type, you would notice a considerable difference to the spiral. That being said, if it is only to one or two machines, and they are short runs, with blast gates at the main, it should work ok for you. If you do use the snaploc type, make sure to tape/seal the long "snaploc" seam, as well as the joint.

If you do cut a branch into the spiral, make sure to leave the overlapped spiral part in, as that is intergral to the stability of the pipe. The metal between the sprials can be removed, but the actual spiral should be left in.


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## Hammer1 (Aug 1, 2010)

Spiral steel dust collection pipe is supposed to be 20% stronger than plain pipe of the same gauge. 
Typically, rigid pipe runs to the machines and a short length of flexible pipe, 2' - 5', makes the final connection. This gives a cushion so the connection isn't solid where vibration or other movement can knock the connection loose. Often a blast gate is added between the rigid pipe and the flex. This can also eliminate hard connections like elbows. Spiral is the way to go for commercial installations


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