View Full Version : PVB With Risers?

08-22-2002, 11:22 PM
Can you use a PVB with 24 inch risers, if the PVB is installed 12" above grade. Should'nt auto drains be installed also? I ask this because this is done here quite often.

Accent Lawn & Garden

Ground Master
08-23-2002, 01:41 PM
I prefer copper and manual drains

08-27-2002, 03:13 PM
Sam, you know that the PVB is required to be 12 " higher than the highest sprinkler head in the site. A riser is a sprinkler head. So with 24" inch risers the PVB needs to be elevated to 36".

Exceptions would be if the PBV location already has a higher elevation the the top of the 24" risers or the location of the risers has higher elevation then the pvb still has to be 12" higher than the top of the riser. Key word being top of the PVB in relation to the top of the riser. 12" differential must be maintained bwteen the top of the PVB and the "highest" sprinkler head on the jon and that could be a pop-up head in the turf.

We have used a builders level in the past to set the right height when necessary. We have moved the location of the PVB the highest site elevation sometimes.

08-28-2002, 09:50 AM
I thought this wasn't right but I see this all the time here. Do you reccomend Double Checks. I've never used them and I thinlk pressure loss would be too great with Reduced Pressure Back Flows. I've mentioned this to this contractor and he just says that's how we do it.


08-28-2002, 10:39 AM
As defined in the national plumbing code a double check is not an acceptable device for cross conection of a sprinkler system. A sprinkler system is a high hazard connection and only PVBs and RPAs are Ok'd for high hazard.

Here in Nj as well as many parts of the country I presume, a plumbing permit must be pulled to do the connection and the decive is inspected after installation.

Some areas require testing of the device periodically but not in NJ or at least not in any municipality where I work.

If you want to protect your butt, you do it to code no matter how lax the enforcement or how ignorant the code officials.

08-28-2002, 11:56 PM
I don' t install risers so I always use a PVB. It's flat land here so no use for RP's. There is also no requirement here for a backflow on an irrigation system. The city only requests them.

A licensed plumber always makes the first service hook up. Cost for this is around $200.00. This is worked into the price of install.

Thought I just might get some more repair work on these installs.

Your advice is always appreciated.


08-29-2002, 01:08 PM
Ok, so they choose not to enforce code.

In today's society I would still do code work and have the plumber mount the device as it is supposed to be. That would minimize future liability.

You may also wish to have a written agreement with him for the hookups that states he is to supply with a connection that meets current codes, enforced or not.

08-29-2002, 11:15 PM
I've spoken with the water department and no one knows what code is for back flows on irrigation. Our parish does not require one. Yes we live in parish's and not counties like you northern folks.
I've spoken to the permit department and a permit is not required if a licensed plumber makes the connection to the water line after the meter. An inspection could be done but rarely happens, I'm told by my plumber.

Most of our lines are copper after the meter. The plumber sweats in a T and installs a shut off valve in a valve box. After this it's all up to me there on. I tie into the valve and get to work.

I always install a PVB at least 14 inches above grade on galvanized pipe. Don't know if this is to state code but this is code in Baton Rouge Parish. This is our state capitol. I buy my Hunter products from a distributor there and this is what they recomend also.

Guess I need to call someone with the state. That will be real fun.
Once again I appreciate your input.


Ground Master
08-30-2002, 03:55 PM
Galvanized?, your kidding, right?........galvanized is the curse of the irrigation industry

08-30-2002, 11:43 PM
No I'm not kidding. I know what you're saying but I called one of my distributors today and this is what is up to code in Louisiana.
They don't even stock copper. I could be using SCH 40 pvc like most here or no PVB at all.

Hey give me a break. This is Louisiana. Our ex gov. is going to prison for life, the Commisioner of Agriculture is on trial and the Insurance Commisioner is also on tiral and both will end up being roomies with the ex governor in prison. Both for taking bribes and tax evasion.

A limit of fish depends on the size of the bottom of your boat.
I could go on if you like.

I don't think the reliablity factor of an irrigation system weighs heavy on the minds of our state officials. I think one of them owns a galvanizing factory.