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Check out my plan please?

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secutanudu

Active Member

Posts: 36

Location: Guilderland, NY (Near Albany)

1

Wednesday, June 30th 2010, 10:30pm

Check out my plan please?

I have 3/4" coming into the meter. I tested pressure on my spigot outside and I have 75-80psi, but that is on half inch. I plant to use 1" for the sprinkler system, how much pressure loss will I get? Currently it immediately drops down to 1/2" just after the meter. This is how I plan to tap into the system for my sprinkler system. Does it look ok? Any concerns?

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HooKooDooKu

Supreme Member

Posts: 683

2

Tuesday, July 6th 2010, 9:51am

System STATIC pressure will be the same no matter what pipe size you use... where pipe size makes a difference is in flowing water... it causes greater restriction and increased fluid "friction", and it's the "friction" that reduces working pressure (along with pressure losses in backflow preventers, valves, and other equipement).

As for your back-flow protection, is the DCBA ok in your area. Some allow it, others require a higher rated device (such as RPZ or PVB).

secutanudu

Active Member

Posts: 36

Location: Guilderland, NY (Near Albany)

3

Tuesday, July 6th 2010, 10:15am

Yup - double-check valve assemblies are approved in my town - just verified that last week from the town.

Wet_Boots

Supreme Member

Posts: 4,102

Location: Metro NYC

4

Tuesday, July 6th 2010, 10:21am

Do yourself a favor and leave some water-pressure "headroom" in your design, in the event you have to trade in the DCVA for an RPZ in the future. If you could locate one properly, a PVB would provide the highest level of protection (no future reworking) with about the same pressure loss as the DCVA

secutanudu

Active Member

Posts: 36

Location: Guilderland, NY (Near Albany)

5

Tuesday, July 6th 2010, 10:28am

The PVB has to be above the highest sprinkler head, right?

Problem is I already purchased the DCVA (a year ago, planned to do this last summer). I don't think I can return it.

Wet_Boots

Supreme Member

Posts: 4,102

Location: Metro NYC

6

Tuesday, July 6th 2010, 11:05am

Just know that codes can change, and the way that they are prone to change will turn the DCVA into a code violation that has to be removed in favor of an RPZ (no grandfathering, when it comes to public safety, and the public water supply) - that's why you don't use every last bit of available water flow. Reducing the flow gives you a higher operating pressure, which is no present worry, but a valuable resource in the event an RPZ replaces the DCVA.

Fireguy97

Advanced Member

Posts: 77

Location: Kamloops, In Beautiful British Columbia

7

Tuesday, July 6th 2010, 11:43am

Quoted from "Wet_Boots"

If you could locate one properly, a PVB would provide the highest level of protection (no future reworking) with about the same pressure loss as the DCVA

Boots, don't go pushing PVB's. In a lot of areas, they are illegal. Yes, they do have about the same pressure loss as a DCVA, but no where on this planet do they provide the highest level of protection.

Mick
Irrigation Contractor

Certified Backflow Assembly Tester

Fireguy97

Advanced Member

Posts: 77

Location: Kamloops, In Beautiful British Columbia

8

Tuesday, July 6th 2010, 11:48am

RE: Check out my plan please?

Quoted from "secutanudu"


I have 3/4" coming into the meter. I tested pressure on my spigot outside and I have 75-80psi, but that is on half inch. I plant to use 1" for the sprinkler system, how much pressure loss will I get? Currently it immediately drops down to 1/2" just after the meter. This is how I plan to tap into the system for my sprinkler system. Does it look ok? Any concerns?

It looks good. 1" would would be good and give you better flow rates.

Mick
Irrigation Contractor

Certified Backflow Assembly Tester

Wet_Boots

Supreme Member

Posts: 4,102

Location: Metro NYC

9

Tuesday, July 6th 2010, 1:04pm

Quoted from "Fireguy97"

Quoted from "Wet_Boots"

If you could locate one properly, a PVB would provide the highest level of protection (no future reworking) with about the same pressure loss as the DCVA

Boots, don't go pushing PVB's. In a lot of areas, they are illegal. Yes, they do have about the same pressure loss as a DCVA, but no where on this planet do they provide the highest level of protection.



Mick
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

PVBs are rated to protect against toxic backflow. This is fact in every location on our planet. RPZ devices are also rated to protect against toxic backflow. At present, most regional code authorities don't define a higher level of risk than "toxic backflow" ~ I do know that some state codes could have employed a classification of "lethal and/or sewage" and that there was no device whatsoever that was allowed in those instances (an "air break" could be used, but that was not an actual plumbing connection)

-

This thread points out the difficulties that arise when the original poster does not supply their location. I would always point towards the choice of toxic-rated backflow protection, because changes in codes almost always lead towards stricter standards. If there are localities with ordinances that require a DCVA, that would certainly be understandable, and those ordinances are no commentary on the fitness of a PVB. In New Jersey, there were numerous communities with DCVA-requiring ordinances, and those ordinances became null and void the moment the state adopted the National Standard Plumbing Code, with its mandating of toxic-rated backflow protection, without any grandfathering of older plumbing. (Of course the fun part was when numerous local plumbing inspectors did not act like they got the memo on the new state code, and continued to try to enforce the obsolete ordinances.)

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The important thing here, is that a properly located PVB provides its protection on the basis of gravity. Water would have to climb uphill in an open pipe in order to contaminate. Gravity is more trustworthy than all the lawyers and inspectors and legislators and insurance companies combined. If you can find an actual legal prohibition to the use of a PVB for toxic backflow protection, feel free to post a link to the legislation. I would like to read it. I expect what there actually is, is a disinterest on the part of inspectors and/or the local/regional governing body to verify that a vacuum breaker is properly installed. Far easier for them to require a device that is indifferent to elevation, even if it is less trustworthy over time than the PVB.

secutanudu

Active Member

Posts: 36

Location: Guilderland, NY (Near Albany)

10

Tuesday, July 6th 2010, 1:30pm

I am located in Albany, NY.

My parents (installed their system last year with a DCVA) live in Stony Point, NY.

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