Water velocity by main line type?
By Tom Lang on Friday, 08 February 2019
Posted in Irrigation
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I sometimes will use DI or Schedule 80 pipe from the meter through my POC equipment, where it will tee into a looped main line.  On larger systems, to keep from having to, say, use 4" pipe at 5fps and have to bush that down to fit a 2" back flow device, I up the velocity to 7.5fps to keep the pipe a size smaller.  What I notice is, if I change one main line's water velocity, they all change.  Is there a way to allow separate velocities by main line type?

A follow-up question:  is this even a good idea, allowing extra velocity through expensive POC equipment?

 

Thanks!

Tom,

I know you and I talked on the phone about this, but a few more ideas here.

 

It’s an interesting dilemma. for instance, we've heard that Ag irrigation alters the velocity. Consider, we assume a different velocity for the lateral line. So an absolutely valid thought, is for instance in Golf irrigation, what if you want your Feeder Mainline, an outer 6" loop, to be at 2fps, but your interior mainline, which is like 3", to be 4fps, and then finally the Laterals at 5fps....

Our redesigned Pipe Data screen was engineered for this eventual possibility!!! So this is something we could consider, having different Classes have different Velocity. But for now, it is considered Best Practice to have Consistent Velocity.

Jake Lott
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6 years ago
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