# DCDA Install



## newyorkcity (Nov 25, 2010)

I am installing a 3" DCDA backflow preventer this week. I have to relocate the piping between the fire service main and the alarm check valve to fit the BFP.
I was wondering:
-Are grooved fittings legal before the water meter? Or must they be flanged or threaded?
-If so, is schedule 40 required, as well as long radius elbows?


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## Lmp (Oct 17, 2011)

newyorkcity said:


> I am installing a 3" DCDA backflow preventer this week. I have to relocate the piping between the fire service main and the alarm check valve to fit the BFP.
> I was wondering:
> -Are grooved fittings legal before the water meter? Or must they be flanged or threaded?
> -If so, is schedule 40 required, as well as long radius elbows?


By dep rules no grooved joints are allow with in the meter set. So if the DCDA your installing has a 3/4 bypass meter that is considered the "meter set". Need to know more info to help you. I have installed many in NYC and have dep code/rule book in my office can send u info if u like


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## newyorkcity (Nov 25, 2010)

Great. Exactly the answer I was looking for. I am going over the DEP water rules now.
Installing a 3" watts 709. Fire service only, no pumps or tanks. 3 story mix use building.
Which fittings do you use for this? Threaded would be easiest.


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## Lmp (Oct 17, 2011)

The 709 comes with a 3/4 bypass meter,that is the meter set. Meaning the 3" fire line can by grooved, threaded etc. also remember you have drill 3/32 holes for the dep seal. There may be more things you have to do but I will need more info about existing fire line.


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## newyorkcity (Nov 25, 2010)

The existing fire line is 3" grooved. Simple wet sprinkler only system. What other info? 
Also, can you send the DEP meter setting section? Thanks a lot.


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## Lmp (Oct 17, 2011)

Is there a existing check valve, test tee , meter etc. I will pm you tomorrow


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## newyorkcity (Nov 25, 2010)

Yes, existing single check with 3/4" bypass meter. No test tee.


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## newyorkcity (Nov 25, 2010)

I went to the DEP office yesterday to pull the meter permit and asked the chief what the rule is. He said that grooved fittings before the meter set is a grey area, and he had a meeting with the other inspectors about it. His advice was since there was 3 fittings and <5' of pipe to do it grooved. I just installed threaded pipe and flanges, prefabbed in the shop. Thanks for the heads up, Lmp. Reach out to me if I can be of assistance.


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## BROOKLYN\PLUMB (May 21, 2010)

newyorkcity said:


> I went to the DEP office yesterday to pull the meter permit and asked the chief what the rule is. He said that grooved fittings before the meter set is a grey area, and he had a meeting with the other inspectors about it. His advice was since there was 3 fittings and <5' of pipe to do it grooved. I just installed threaded pipe and flanges, prefabbed in the shop. Thanks for the heads up, Lmp. Reach out to me if I can be of assistance.



Doesn't the dcda have as it's inlet valve flanged on one side (inlet) and vic connecting before meter? 

That's why it's a grey area also a violation that I've gotten was the test tee built into the bypass meter setup is located before the meter And its supposed to be after (dep is a pain and each borough is different as well as each inspector


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## newyorkcity (Nov 25, 2010)

The DCDA I purchased from Bruce is flange x flange. A pic is attached. I know the "S" trap is no good. I will vent the funnel drain although it will be tough. Needed a drain in case the relief discharges.
I like doing jobs for the military. I was laughed at once when I asked if we need permits to work on the gas at an army base. I was told "this is the army-we don't need permits. Do you really think we will let an inspector in here?"
Feel free to correct me on any problems here.


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## Lmp (Oct 17, 2011)

I can't see the pic


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## bml (Feb 8, 2011)

Is this a new DCDA, or a replacement of an existing? Have hydraulic calculations been performed to make sure the system can supply the necessary water in a fire condition with the additional friction loss through the DCDA?


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## newyorkcity (Nov 25, 2010)

Of course hydraulic calculations have been made. I hold licenses in plumbing and fire sprinklers. I paid a PE to provide plans which were reviewed and approved by DEP. I also pulled a permit for the BFP install, and a permit for the water meter install. That is three separate approvals followed by two backflow tests, one on the 3" and one on the 3/4" bypass, to be submitted on the GEN 215 form. This device replaces a single check valve.


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## bml (Feb 8, 2011)

newyorkcity said:


> Of course hydraulic calculations have been made. I hold licenses in plumbing and fire sprinklers. I paid a PE to provide plans which were reviewed and approved by DEP. I also pulled a permit for the BFP install, and a permit for the water meter install. That is three separate approvals followed by two backflow tests, one on the 3" and one on the 3/4" bypass, to be submitted on the GEN 215 form. This device replaces a single check valve.



:thumbsup:


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## newyorkcity (Nov 25, 2010)

That being said, I am here to learn. I have 20 years of "trial by fire" experience in the plumbing business. I have a nice sprinkler job coming up which I could use some real life experience tips. I study NFPA 13 every chance I get. I would like to read your input on tips to handle an upgrade on an occupied building with drop ceilings. Do you use flexible connectors?


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## bml (Feb 8, 2011)

newyorkcity said:


> That being said, I am here to learn. I have 20 years of "trial by fire" experience in the plumbing business. I have a nice sprinkler job coming up which I could use some real life experience tips. I study NFPA 13 every chance I get. I would like to read your input on tips to handle an upgrade on an occupied building with drop ceilings. Do you use flexible connectors?



The flexible drops can be the way to go in a lot of situations. They do have a few downsides, however. One of them being that the equivalent length of some brands is so large that it makes them hard to use if the water supply is lacking. Just make sure whoever performs your calculations is aware of your desire to use flex drops so they can calculate it correctly.

Also, I am not familiar with New York specific codes, since I'm from the SE. Make sure they are approved for use in your jurisdiction, and by your customer/building owner and their insurance company.

The flex drops are expensive, and it usually takes a little practice to take advantage of the labor savings they offer, but one you get the hang of it, they go in pretty quick. There are specific requirements for minimum bend radius, etc., so be prepared to trash a few of them in the learning process.


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## newyorkcity (Nov 25, 2010)

How about exposed upright sprinklers? What is your average height from the deflector to the ceiling?


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## bml (Feb 8, 2011)

newyorkcity said:


> How about exposed upright sprinklers? What is your average height from the deflector to the ceiling?



It really depends on the individual situation. If it is unobstructed construction, then generally I'll put them a few inches below the ceiling. NFPA 13 requires them to be between 1-12 inches from the ceiling/roof.


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