Backflow install question

In Tampa, FL I've decided to install an inline "fertigation" unit to my irrigation system, so now I'm learning about backflow preventers.

I believe the first picture is an example of an Atmospheric Vacuum Breaker (anti-siphon), which I read is not recommended, so I picked up a brass Pressure Vacuum Breaker at Lowes today. I was reading up on those when I came across the second picture showing the installation height of 12" above the highest outlet.

I have several sprinklers on 3 foot extensions with a popup (as came with the house). Do I seriously have to make a 4 foot high install? The first picture is the current install as is, basically on grade.

Atmospheric Vacuum Breaker do have to be 12' above your highest head. But you can also use a double check device that can be installed 12" above ground level.

3' extensions raiser plus a pop up sprays= 4' tall (or more) so your AVB or PVB shall be at 5' (12" above highest outlet). I would use a DC or an RPz (install 12" to 36" above ground).

gargalaxy said:

3' extensions raiser plus a pop up sprays= 4' tall (or more) so your AVB or PVB shall be at 5' (12" above highest outlet). I would use a DC or an RPz (install 12" to 36" above ground).

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I think that's what I said.

johnjh2o said:

I think that's what I said.

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[ame="https://www.youtube.com/watch?v=CUPHqhotql0"]https://www.youtube.com/watch?v=CUPHqhotql0[/ame]

Thanks. Since I'm setting up inline chemicals I'll go with the RPZ.