Cross connect requirements for drip system

[john_incircuit]

We are primarily grass cutters, not irrigation installers. For my own yard, I want to go ahead and use the downtime to install a small drip irrigation system. This system will be fairly basic, 300 feet of ½ inch hose, drip emitters and the ¼ inch feeders.

My primary question is about the cross connect requirements. I calculated the water consumption, checked the pressure and plan to connect the system to my outside water faucet as needed (via a basic check valve, pressure reducer and water filter). The check valve is one of the $5 plastic “orbit” back flow preventers.

In our area, all sprinkler systems need an approved, double check valve backflow setup, but they connect directly to the street main. What about a drip system that connects temporarily, via garden hose, to the existing outside water faucet?

Thanks for the help!!

[AI Inc]

you can do it that way but by law you should realy have a better backflow preventer then what you plan on using.

[londonrain]

Call your local water purveyor and talk with the cross connection control manager and ask what their requirements are for your situation....

[Dirty Water]

Install atmospheric vacuum breaker after the valve and you will be fine. I'm assuming hose thread since its coming off a faucet. Something like this is designed to go inline.

http://www.watts.com/prod_images/N9-CD.jpg

http://www.watts.com/pro/_productsFull_tree.asp?catId=65&parCat=95&pid=889&ref=2

[Hank Reardon]

Call your local water purveyor and talk with the cross connection control manager and ask what their requirements are for your situation....

Ditto, install to code.

[Kiril]

I would agree with DW. No different than connecting a hose to the hose bib, therefore hose bibb vac break should suffice. I suppose if you want to be safe, check with the city.

[john_incircuit]

Ditto, install to code.

I want to do it to code, no question. I assume this means that the code does not distinguish if I tap into the street connection or the outside faucet? If this is correct, what type of back flow prevention are built into the dishwasher or washing machine for example?

[Kiril]

I want to do it to code, no question. I assume this means that the code does not distinguish if I tap into the street connection or the outside faucet? If this is correct, what type of back flow prevention are built into the dishwasher or washing machine for example?

I believe most codes do distinguish between the two, the latter only requiring a hose bibb vac break. I personally have not seen any other requirement on a hose bibb, but then there are places like Suffolk Co. where upside down is right side up and double checks are considered suitable for hazardous cross connection control.

[Dirty Water]

I want to do it to code, no question. I assume this means that the code does not distinguish if I tap into the street connection or the outside faucet? If this is correct, what type of back flow prevention are built into the dishwasher or washing machine for example?

dishwashers use an air gap on the drain line, and usually no back flow at all on the positive line.

[Hank Reardon]

I want to do it to code, no question. I assume this means that the code does not distinguish if I tap into the street connection or the outside faucet? If this is correct, what type of back flow prevention are built into the dishwasher or washing machine for example?

That's why I was supporting LR's suggestion to call your water purveyor and get what the requirements. Using the item DW posed might be acceptable in some places, it wouldn't be here where I live.

[Dirty Water]

That's why I was supporting LR's suggestion to call your water purveyor and get what the requirements. Using the item DW posed might be acceptable in some places, it wouldn't be here where I live.

WA has some pretty messed up rules if they allow a doublecheck but prohibit a AVB...properly installed of course.

The AVB I posted is no different than any other AVB's, it is just designed to go inline for a hosebib.

[zman9119]

...what type of back flow prevention are built into the dishwasher or washing machine for example?

Most (if not all) have check valves built into them. They are also not listed as high hazard like irrigation is.

[Mike Leary]

Any outlet with air gap is up to code, however, should drip or micro be connected, it
becomes a cross-connection & no screw-on vb should be permitted.

[Hank Reardon]

WA has some pretty messed up rules if they allow a doublecheck but prohibit a AVB...properly installed of course.

The AVB I posted is no different than any other AVB's, it is just designed to go inline for a hosebib.

How many of those have you seen installed below the highest head! :rolleyes:

[Kiril]

How many of those have you seen installed below the highest head! :rolleyes:

With respect to the WA dudes, hose vac breaks are health hazard rated, double checks are not. Personally I would be questioning the use of a double check more than I would a hose bibb vac break. Most of the hose bibs coming off houses are at least above grade, even if they are not all above the majority of the sprinklers.

[Hank Reardon]

With respect to the WA dudes, hose vac breaks are health hazard rated, double checks are not. Personally I would be questioning the use of a double check more than I would a hose bibb vac break. Most of the hose bibs coming off houses are at least above grade, even if they are not all above the majority of the sprinklers.

WDOH does not see irrigation as high hazard.

[h2oman]

I don't know where you live in ny but a simple check into your town codes can help solve any problems. By doing a simple search this is what I have found. www.townofgreece.org/planningdevelopment/TechnicalServices/sprinklers.htm
NYC codes are different, and so is everybodies here. So check out your county codes. Good luck.

[john_incircuit]

I went to the town hall to discussed the backflow requirements for the basic drip system I want to hookup directly to the outside faucet.

-- They “like” the Watts N9 “Field Testable Dual Check Vacuum Breaker with Atmospheric Vent” http://www.watts.com/pdf/es-n9-cd.pdf that Dirty Water suggest.

-- Back in my office, when I read the code book, I came across this sentence: “ …. a valve shall not be installed downstream from an atmospheric vacuum breaker”.

Not sure why a valve would not be allowed after a vacuum breaker, does this mean that the application in the picture below is not to code now?

Thanks for the help!!

[Kiril]

There is a difference between AVB (atmospheric vacuum breaker) and a PVB (pressure vacuum breaker). Since your "valves" are not under constant pressure, I would say that sentence does not apply.

[Dirty Water]

An atmospheric vacuum breaker must be installed downstream of a valve, not before it.

In order for you to be to code, you would need a AVB after each of your three valves, assuming you plan on leaving the hosebib open all the time.

[AI Inc]

WDOH does not see irrigation as high hazard.

Maybe not , but national plumbing code does.

[Wet_Boots]

Maybe not , but national plumbing code does.the National Standard Plumbing Code (http://www.phccweb.org/Contractor/content.cfm?ItemNumber=736) is actually a regional code. despite the name. But it is adopted by a number of states. I would expect most regional codes to want toxic-rated backflow for irrigation, on the basis of the simple logic of what might be the nature of the backflow. (fertilizers, pesticides, animal contamination, septic fields) ~ if a code doesn't require it, it only means to me that they haven't really looked closely at the nature of the potential risks. Or maybe there is so much entrenched non-compliant usage, that they just don't want to go there.

[Kiril]

I like to use the National Common Sense Code when it comes to things like health hazards. :)

[john_incircuit]

I’m not a plumber and may not understand the multiple failure mechanisms correctly, but I’m just not clear on what difference a simple inline, on-off valve makes on the correct function of the Watts vacuum breaker. Thinking through the 6 basic failure modes of a valve (fully closed, fully open, partial closed, partial open, leaking water, or letting air in), I can’t visualize how each scenario would compromise the backflow prevention. What is it that I don’t understand on why a valve can not be downstream of a vacuum breaker?

[Wet_Boots]

AVB's can't be pressurized 24/7 and still function.