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  1. #1
    Join Date
    Apr 2008
    Posts
    169

    long copper runs shifting in their holders

    I've been running into this problem of long (100' +/-) runs of discharge lines migrating in one direction, and the Hydra-Zorb' style clamps and racks shifting, to the point of bending their all-thread hangers. The hangers seem to be doing a ratchet' affect rather than expanding and returning to a neutral position. Neither of the isolator clamp manufactures I spoke to had any help or seem to know of this.
    So far our approach has been to brace most of the hangers in the horizontal direction and for the most part the lines have settled in to where they want to land. But now I've found pair of liquid lines doing it and looking for some advise.

  2. #2
    Join Date
    Nov 2007
    Posts
    388
    You did not design the pipe run for thermal expansion of the piping system. In simple terms, copper expands 0.011" for every 100 foot for every deg of temperature difference. So if you installed 100 ft of copper outdoors with an 10 deg F OA temp and during the summer the piping will be subjected to 95 deg F temperatures then the piping needs to be designed for a thermal expansion of:

    0.011x(95-10)=0.935" of expansion

    If the piping is constrained with clamps, it will buckell, or rip out hangers. To prevent this, I put in expansion loops or expansion compensators....remember Google is your friend!

  3. #3
    Join Date
    Oct 2007
    Location
    Milwaukee,WI
    Posts
    1,100
    x2 on the expansion loops
    ___________________________

    Chicago is an indian word for stinky!!!!!!
    -supertek65

  4. #4
    Join Date
    Sep 2002
    Posts
    13,551

    Silicone the Hydrosorb inserts

    And they will slide back and forth.

    Now they are doing what you suspect; ratcheting the pipe one way but not in reverse.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  5. #5
    Join Date
    Apr 2008
    Posts
    169
    Quote Originally Posted by Poodle Head Mikey View Post
    And they will slide back and forth.
    Now they are doing what you suspect; ratcheting the pipe one way but not in reverse.
    The silicone seems like a logical idea and something I hadn't considered. Have you (or others) used this successfully? Thinking for the long term, I want to avoid doing things that will allow the lines to reset' from their current position only to have them shift again. Should we expect to have to reapply' at some time for example? We did find that loosening the clamps didn't stop the ratcheting effect.

    So, as I attempt to rethink this..
    View the 90 degree turns as 'Z flex points. Long straight runs should float' not clamp. Clamp' and/or 'float where needed to control or direct the movement.
    The 'Hydra-Zorbe style clamp isn't even appropriate in a large part of these applications.
    A cautious 'so far so good?

  6. #6
    Join Date
    Aug 2008
    Location
    Burlington , Mass
    Posts
    470
    Somewhere in that long run, usually at the middle (50ft) you make an expansion point. _____
    __________/ \__________.


    I havent had to do this since the 70's when we built supermarkets, but it applies to most piping be it refrig, steam, hot water etc.

    I dont remember the formula used to calculate the size of the loop
    I'll be there when I get there and not a minute later

  7. #7
    Join Date
    Sep 2008
    Location
    Cedar Rapids, IA
    Posts
    487
    In our supermarket installs we do not use hydrosorbs on the trapeze hangers. Walmart requires us to put a PVC sleeve on top of the unistrut and the refrigeration line including its insulation goes thru it. One PVC sleeve per each copper line. The refrigeration line is not attached to the trapeze so it is free to move. The PVC is about 6" to 1' long depending on the weight of the line to prevent crushing the insulation. Its attached to the unistrut w the heavy duty plastic ties that are used for ductwork (2 of them criss crossed)

    This has several advantages over using hydrosorbs. The thermal expansion joints are often not necessary, which means you could retrofit w/o having to evacuate and cut the lines. Also it is easy to maintain a vapor seal to prevent ice and condensation from dripping. But I suspect that Walmarts main motivation is cost.

    At any rate it works well and we use it on other jobs too.

    To retrofit cut a slot in the top of PVC sleeve so you can slip it around the exisiting pipe, don't cut it in half and use only half as your ties will bind on the insulation.

    We usually cut up the 20' PVC pipe lengths with a chop saw.

  8. #8
    Join Date
    Apr 2008
    Posts
    169
    Quote Originally Posted by bob_scheel View Post
    In our supermarket installs we do not use hydrosorbs on the trapeze hangers. Walmart requires us to put a PVC sleeve on top of the unistrut and the refrigeration line including its insulation goes thru it. One PVC sleeve per each copper line. The refrigeration line is not attached to the trapeze so it is free to move. The PVC is about 6" to 1' long depending on the weight of the line to prevent crushing the insulation. Its attached to the unistrut w the heavy duty plastic ties that are used for ductwork (2 of them criss crossed)

    This has several advantages over using hydrosorbs. The thermal expansion joints are often not necessary, which means you could retrofit w/o having to evacuate and cut the lines. Also it is easy to maintain a vapor seal to prevent ice and condensation from dripping. But I suspect that Walmarts main motivation is cost.

    At any rate it works well and we use it on other jobs too.

    To retrofit cut a slot in the top of PVC sleeve so you can slip it around the exisiting pipe, don't cut it in half and use only half as your ties will bind on the insulation.

    We usually cut up the 20' PVC pipe lengths with a chop saw.
    Sounds good. Seems like I'd want something soft in there between copper and PVC?

  9. #9
    Join Date
    Jul 2001
    Location
    Gold Coast of Connecticut
    Posts
    4,663
    Quote Originally Posted by bob_scheel View Post
    In our supermarket installs we do not use hydrosorbs on the trapeze hangers. Walmart requires us to put a PVC sleeve on top of the unistrut and the refrigeration line including its insulation goes thru it. One PVC sleeve per each copper line. The refrigeration line is not attached to the trapeze so it is free to move. The PVC is about 6" to 1' long depending on the weight of the line to prevent crushing the insulation. Its attached to the unistrut w the heavy duty plastic ties that are used for ductwork (2 of them criss crossed)

    This has several advantages over using hydrosorbs. The thermal expansion joints are often not necessary, which means you could retrofit w/o having to evacuate and cut the lines. Also it is easy to maintain a vapor seal to prevent ice and condensation from dripping. But I suspect that Walmarts main motivation is cost.

    At any rate it works well and we use it on other jobs too.

    To retrofit cut a slot in the top of PVC sleeve so you can slip it around the exisiting pipe, don't cut it in half and use only half as your ties will bind on the insulation.

    We usually cut up the 20' PVC pipe lengths with a chop saw.
    Exactly how I do it as well.
    Aire Serv of SW Connecticut- Gas heat, dual fuel and central a/c systems installed and serviced

  10. #10
    Join Date
    Sep 2008
    Location
    Cedar Rapids, IA
    Posts
    487
    Quote Originally Posted by mixsit View Post
    Sounds good. Seems like I'd want something soft in there between copper and PVC?
    The armor flex insulation lies directly on the pvc w/o any problems. When the pipe thermally expands it usually moves within the insulation and doesn't drag it back and forth.

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