dripping in the fire sprinkler system

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by guo2013, Jun 16, 2013.

  1. guo2013

    guo2013 New Member

    Messages:
    3
    Location:
    PA
    My home has a fire sprinkler system. Today I found that there is water leaking from the pipe. It is about one drip every 5-6 seconds. The location is labeled by the pink color in the pictures. There is a pressure-reduce valve after the water meter. I donot know the name of the component of leaking. It is after the pressure-reduce valve in the fire sprinkler system. The leaking is from underneath of this component. Is it easy to fix?

    Actually today I noticed that the water pressure in the fire sprinkler system is a little bit of high (about 85), it should be 75. So I shut off the water valve in the fire sprinkler system and release the pressure by opening the drain. Then I turn on the water valve in the fire sprinkler system. I think that this leaking is after I did this. Did my operation cause this leaking? Now the water pressure in the fire sprinkler system come back to 85. The water pressure problem also happened about two years ago ( the pressure was 125). I did the exact same operation to reduce the the water pressure. The water pressure remain 75-80 during last two years.

    Now it seems that my method to reduce the water pressure is not working any more. Does it mean the water-pressure valve in the fire sprinkler system has some problem, and I should replace it?

    Thank you very much :)

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  2. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,383
    Location:
    Yakima WA
    I know nothing about fire suppression plumbing, but that fixture in question certainly resembles a back flow prevention device. If it is, it not DIY repairable. Whether my guess is correct or not, it would be my recommendation that you call a fire suppression installer in your area and arrange a service call.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,020
    Location:
    Cave Creek, Arizona
    valve

    That is a "reduced pressure principal back flow preventer" which is either malfunctioning, or functioning properly. There is no way to tell which without testing it with the proper equipment. Repairing it is not really a DIY task, and can be frustrating if you try, since it will probably still leak when you get done, and may leak worse.
  4. guo2013

    guo2013 New Member

    Messages:
    3
    Location:
    PA
    I guess that the leaking could be due to the debris in the public water, because the leaking is after I did the draining operation by turning on the faucet in the fire sprinkler system. Maybe I can turn on the faucet one more time, so the debris in the backflow prevention device will go away? Can I do this? Last time when I do this, the water pressure in the fire sprinkler system almost drops to zero. Will this water pressure change(from around 85 to zero, then from zero back to 75) has any affect to the fire sprinkler system?

    Actually last time when the water pressure in the fire sprinkler system is very high (about 125), the plumber did the draining operation and he said that maybe some debris is in the pressure-reduction valve. After he did this, the water pressure was back to the normal.

    I did some research and some website said that the water in the fire sprinkler system could flow back to thehousehold water supply if the backflow prevention device has the problems. Now my backflow prevention device is leaking, is it possible that the water in the fire sprinkler system is flowing back to the household water supply? How to know if the water in the fire sprinkler system is flowing back or not? I am kind of worried about this, since I heard that there is anti-freeze in the fire sprinkler system.

    thank you very much.
  5. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,383
    Location:
    Yakima WA
    You don't seem to grasp the advice we've given you. This is not a DIY job. The device is a little different from those used in irrigation systems that use domestic water, but they do the same job. That is, they prevent contaminated water from the system from reentering the domestic supply. Think of this. You have a fire, the sprinklers open and do their job, but in the aftermath, there will be tons of contaminated water in the fire system. If there is no working back flow prevention, that contamination would get into the entire city water main. That's why these devices should be certified by a licensed professional on a periodic basis. My device must be check and certified annually. There must be at least one business close to you that installs and maintains fire suppression systems. Usually the repairs, if needed, amount to an O ring or two, and maybe a spring. Again, not a DIY job.
  6. Sean Beck

    Sean Beck Plumber

    Messages:
    68
    Location:
    Toronto, Ontario, Canada
    The water in the fire sprinkler system won't backflow into your potable water supply. That is what the atmospheric port is for. Water will drain through the port should there be a malfunction in the valve, or a pressure change in the system.

    The RP backflow preventers can only be tested by certified personnel. There is a chance that you may need to replace the valve. I would install a new RP backflow preventer and check the recommended supply pressure in the manual. Make sure that you're pressure reducing valve is functioning properly and keeping the pressure within the recommended guidelines.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,020
    Location:
    Cave Creek, Arizona
    leak

    Opening and closing faucets has absolutely NO EFFECT on the valve that is dripping. You have to open the "fire system test valve" at the end of the fire lines to flush water through the valve. If your system is monitored, call the company FIRST, otherwise it will register as a fire and the fire department will respond and maybe charge you for a "false alarm".
  8. guo2013

    guo2013 New Member

    Messages:
    3
    Location:
    PA
    Thank all of you for reply.

    This backflow prevention device never leaks before. The leaking happened right after I opening and closing the faucets in the fire sprinkler system. So I suspect that there is something to do with the opening and closing of the faucets. The faucets is labeled as "DRAIN". What is this faucet used for? From the website of some fire protection system company, I know that the one of the reasons for leaking is that the debris from the public water does not allow the gaskets and the springs to seat properly. So the water is leaking from the relief valve.

    I am not trying to DIY this. If the opening and closing the faucets can fix the problem, I will try. If not, I will call the professionals to fix.

    Hi Sean,

    You mentioned that the water in the fire sprinkler system won't backflow into my potable water supply. I did not see atmospheric port in my fire sprinkler system. Is it near to the backflow prevention device? Is it connected to the sewer? I did not see that the fire sprinkler system is connected to the sewer pipe. I will get the professionals to get it fixed soon. But before I get it fixed, my main concern is that the water in the fire sprinkler system will backflow into my potable water supply if the backflow prevention device does not work properly.

    Thanks a lot for your guys.
  9. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,383
    Location:
    Yakima WA
    I stated in my first reply to this question that I know nothing about fire suppression systems, but I do have a basic concept of backflow prevention for lawn irrigation. The term "back flow preventor" certainly implies that they are present to stop contaminated water from getting into and spreading contamination to the main water supply, and assuming this supply is the city water main, yes this is your potable water supply. It is absolutely not connected to the sewer in anyway. DUH. The type of device you have relies on springs and seals that will seal and prevent the back flow. Lawn back flow preventors are supposed to be inspected, tested, re-certified annually by a licensed inspector. I can see no reason why a fire suppression back flow preventor would not have a similar requirement. In my opinion, you are wasting time and effort trying avoid have the inspection that you really should have. Is is possible there could be some kind of debris in the device? I sure don't know, but an inspection and testing would answer that question as well as making sure the system was operating correctly. Cost of inspections probably will vary for place to place, but just as an example, my inspector charges $35. Other inspectors rates range up to $50. Maybe the size you have would be a factor, but still it is not going to be a prohibitive expense.
  10. Mark Potter

    Mark Potter New Member

    Messages:
    4
    Location:
    NY
    Residential systems should not be tied to the city or town line or your home water plumbing, get a company in there. Depending on we're you reside you need licensed fitter to install, permits and inspections FDC connection ect.
  11. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,020
    Location:
    Cave Creek, Arizona
    quote; Residential systems should not be tied to the city or town line or your home water plumbing,
    In that case WHERE should it be connected, since that is usually the only source of water in the building. ALL residential systems connect to the house water line. In fact, some of the new systems use the house plumbing for the fire mains.
  12. Smooky

    Smooky Member

    Messages:
    624
    Location:
    NC
    Normally an air gap fitting would be attached to the back flow preventer below the atmospheric vent. Then it would be piped to a drain. Sometimes trash can get caught in the relief valve or check valves and may cause it to leak. It is recommended to install a wire mesh strainer in the water line before the RPZ to help prevent trash from getting into it. When there is a change in pressure some water may leak out also. The seals can go bad etc and need replacement. This type of valve should be tested yearly.

    http://www.shopbackflow.com/shopping/Products/34-1-909--1--1-12-009-AIR-GAP__0881376.aspx

    http://media.wattswater.com/ES-009.pdf (this one takes about a minute to download)

    http://media.wattswater.com/ES-745.pdf
    Last edited: Jul 20, 2013
  13. Mark Potter

    Mark Potter New Member

    Messages:
    4
    Location:
    NY

    For residential with well water needs to have multi tanks in a basement, these tanks hold about 4-600 gallons there usually 2 or 3 pending size of the home.
    For town or city water it should get hooked sepretly to the main outside seperation from home. It won't be enough pressure if its hooked to the home and if your pipe brakes for a toilet expect the fire department to come lol

    You can not use house plumping to feed sprinkler system and the sprinkler heads. This requires cpvc pipe to the heads and schedule rated pipe. Copper or pex shouldn't be used either.
  14. MACPLUMB 777

    MACPLUMB 777 TROJAN WORLDWIDE SALES RP

    Messages:
    679
    Location:
    Houston, Texas, United States
    #1 Mark Potter you need to stop posting about something you know nothing about !

    #1 House fire sprinklers do come off the same water meter and supply as the house,
    #2 Both copper and pex are accepted for fire sprinkler systems,
    #3 As to what was posted earlier almost all new home systems are piped with pex in a circle fashion for both potable water and the sprinkler use,
  15. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,020
    Location:
    Cave Creek, Arizona
    quote; It won't be enough pressure if its hooked to the home and if your pipe brakes for a toilet expect the fire department to come lol
    You can not use house plumping to feed sprinkler system and the sprinkler heads. This requires cpvc pipe to the heads and schedule rated pipe. Copper or pex shouldn't be used either.

    Unless the house system is used as the fire system piping, the connection is at the entry to the house and ONLY a head discharge will activate the alarm. Using the house piping as part of the sprinkler system is how many new installations are done. CPVC pipe is used because it is CHEAPER, and faster (which is the same thing), to install. But, ANY piping can be used, even black steel if you wanted to go that way. YOu either do NOT know how they are installed or are way behind the times.
  16. Mark Potter

    Mark Potter New Member

    Messages:
    4
    Location:
    NY
    Oh boy guess you guys aren't licensed fitters. I know for a fact in my location you can not use copper or pex from main to the heads. And you also need permits and inspections on the installs.
  17. MACPLUMB 777

    MACPLUMB 777 TROJAN WORLDWIDE SALES RP

    Messages:
    679
    Location:
    Houston, Texas, United States
    No I am not a fitter however I am a licensed fire sprinkler master installer since Jan 1989,
    Yes you need permits and inspections ever where on new construction how ever this is an existing installation,
    and as such only needs to be recertified once a year or as local code requires
    Last edited: Jul 20, 2013
  18. Mark Potter

    Mark Potter New Member

    Messages:
    4
    Location:
    NY
    I am aware of residential systems being installed this way were every thing is looped from sprinkler back to fixture and vice versa, IMO it's not method in which is better.
  19. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,383
    Location:
    Yakima WA
    You know all of this arguing back and forth is pointless. As I stated way back when: this is not a DIY job. The man needs a licensed fire installation person to fix this problem and it doesn't make squat what the problem is.
  20. MACPLUMB 777

    MACPLUMB 777 TROJAN WORLDWIDE SALES RP

    Messages:
    679
    Location:
    Houston, Texas, United States
    Exactly Gary thank you, my point
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