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burley

Active Member

1

Thursday, May 31st 2007, 9:06pm

backflow preventer for uphill zone

I have one uphill zone on a rather steep 40' slope. I understand I can use a reduced pressure principle (RPP) assembly, and I can afford the 15 psi pressure loss, but I'm concerned about the cost, complexity, and testing requirements.

I'm considering using one PVB for all the downhill zones and using an AVB on the top of the hill for the uphill zone. I know AVB's are frowned upon, but I know a lot of people (in Southern California at least) use anti-siphon valves which are really just a valve with an integral AVB. Is an AVB really any worse than an anti-siphon valve? I suppose I could use an anti-siphon valve, but I really don't want the wires exposed on the hill and I don't want to run a pressurized mainline up the hill either.

Are there any other options for dealing with an uphill zone?

Wet_Boots

Supreme Member

Posts: 4,081

Location: Metro NYC

2

Friday, June 1st 2007, 3:19am

I could only see an AVB as a retrofit item, and an inferior one at that, since all the pipe on the hill upstream of the AVB would not be protected.

burley

Active Member

3

Sunday, June 3rd 2007, 3:10pm

Why would protection of the pipe upstream of the AVB matter? We're talking about 40' of pipe between the valve and the AVB. There's another 100' or so of mainline that wouldn't be protected too. But why would that matter? Is the main concern that a backflow condition might occur at the same time as a pipe failure incident?


Wet_Boots

Supreme Member

Posts: 4,081

Location: Metro NYC

4

Monday, June 4th 2007, 5:39am

Who commanded the upstream pipe to be forever unbreakable? Use an RPZ at the point of connection, and it's job done, and everything beyond the RPZ is isolated from the drinking water.

Fertigation Guru

Active Member

Posts: 42

Location: USA

5

Monday, June 4th 2007, 10:39am

RPZ is definitely the way to go on this one. You do have to have them inspected annually, but it would be the simplest option for your situation.

burley

Active Member

6

Monday, June 4th 2007, 6:48pm

Thanks guys. Sounds like I'll have to go with the RPZ.

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