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Copper tubing question for shop heater.

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  • Copper tubing question for shop heater.

    I finally gave up on my wood burning stove as a shop furnace, went to an old 30K Wall mount outside vented unit that leaks like a sieve and most recently parted with some hard earned cash (about $550 so far ) for a Propane 60K BTU Ceiling mount garage type unit.

    I went to Home Depot to buy some tubing. As I stood there gazing up at the overhead rack with my jaw wide open at the tubing sizes it occured to me, "hey, this sh1t is expensive, I better buy the right stuff".

    Their's was marked "refrigeration grade". Can anyone tell me if that will work for my propane/nat gas needs? I would have asked a store rep but as usual, he was busy cashing people out and evidentally the other guy was taking a dump. No staff in a huge store?

    Also, I'd like to make a 50 Foot run with the tubing. Will 3/8's be large enough to carry a 60K input load of both Propane or Nat Gas. (I hope to convert to Nat Gas in the furture and would like to use the same tubing)

    As always, any advice would be appreciated.

    this is the unit I got:
    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    Thank you to our families of soldiers, many of whom have given so much more then the rest of us for the Freedom we enjoy.

    It is true, there is nothing free about freedom, don't be so quick to give it away.

  • #2
    Good question YOD, I'm hoping someone with more experience will chime in here and enlighten both of us.
    All of the installations I have seen here are all black steel tubing but a quick look around tells me that copper tubing is certainly acceptable in some cases. It may come down to local code requirements.

    Have a look at a couple of links on copper gas line types that are some areas anyway. I think it best to check with a local heating contractor to find the specifics on local code though, your insurance broker may abandon you when you need him the most!
    Home, down in the valley behind the Red Angus
    Bad Decisions Make Good Stories​

    Location: British Columbia


    • #3
      Gas Supply

      I would not use copper tube for a gas supply line. A lower cost method is the old reliable black steel pipe. For a long run I would go to a minimum of 3/4 inch. I have seen natural gas that contains a little H2S and that reacts with the copper to form an oxide that flakes off and can present major problems with the control valve. The small tube mught work for the higher pressure Propane. The latest type of gas line is the corrugated stainless steel with a yellow plastic jacket for identification.



      • #4
        Mine is installed to code here with copper tubing at 2 psi from the meter to the furnace. Refrigeration tubing should be fine, but mine is 1/2" all the way to the regulator near the furnace and after for a few feet with a flexible 1 meter connection at the end to the furnace. Other appliances such as the kitchen stove may use 3/8 tubing from a central manifold I installed with 4 nipples and a valve at each end for easy hookup of new appliances.

        The heater I have is a free standing natural gas convection heater with no requirement for electricity. It is self generating for a remote thermostat upstairs. It has cold air makeup and a lined flue to itself in my three flue chimney.

        There is a fan unit beside it on the floor that powers air up to a nozzle just under the grate in the main floor above. It is located in the center of the house and the airflow is enhanced by the hot air collected above the heater and entrained in the air injected from below. When the heater isn't running the air coming in the cold air return is picked up by the floor fan and mixed with the warm air above by the air injector. In case anyone wonders about the thickness of the floor under the grate my floors are three inches thick solid wood.

        The chimney is a massive structure with a total mass of around 20 tonnes. It serves as a very effective thermal mass structure for the wood burning stove which is just to the right of the gas heater.
        Free software for calculating bolt circles and similar: Click Here


        • #5
          Thanks guys. I asked the gas company years ago about copper and they said in our part of the world it was OK as the nat gas we use is low sulfur content. They did say it had to be encased in sand if buried to keep it away from rocks.

          All of my piping copper piping will be above ground, even at the point where I'll eventually convert to nat gas.

          Now that I know "refrigeration grade copper" will work for my needs I just have to find out if 3/8 ID will handle 60K BTU of gas. Once found a great chart on web and have not been able to relocate it. I'll keep looking for the chart.

          When I make my run from the house to the barn it will be 1" black iron to the 50' piece of 3/8 copper but that's a year or two off. We are planning another out building and I'd like to do it all at once.

          Evan thank you for taking the time to post the pics.
          - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
          Thank you to our families of soldiers, many of whom have given so much more then the rest of us for the Freedom we enjoy.

          It is true, there is nothing free about freedom, don't be so quick to give it away.


          • #6
            My furnace is 60k input. I think you will need 1/2" tubing.


            3/8" will work for propane as it has a higher heat content but for ngas you will need 1/2" for a 50' run.
            Last edited by Evan; 12-13-2007, 01:25 PM.
            Free software for calculating bolt circles and similar: Click Here


            • #7
              I was told that the issue with copper is that mercaptin (the ingredient added to create the odor so leaks are obvious) would attack copper. The local utility discourages it, but even at that, it is still allowed by code. They do require that just prior to where it meets the black iron pipe that feeds into your gas valve, you must have a "drip leg". This allows the black scale that forms inside as it is corroded, to drop and not end up in the valve itself.

              I don't like the idea of soft copper in a shop at all. Its too easy to ding something into it and make a big mess or a fire. Even bumping it a few times over the years can end up inducing a stress crack. In my case, they use buried soft copper from the LP tank to the secondary regulator at the building entrance, from which I used black pipe to get up very close to my overhead heater. At that point, I have a short "appliance connector" (those corrugated stainless flexible pipes) that ties from black iron to the gas valve. There also needs to be a shutoff in that line, within arms reach of the gas valve. Shutoffs, and connections to secondary regulators etc. etc. are always done more safely with black iron pipe because they don't flex when making connections or turning the valve on and off etc. Same goes for the ability to add a drip leg, which I did right where the iron pipe comes into the building and again just before the gas valve on the furnace.

              Good luck, and be safe.

              Paul Carpenter
              Mapleton, IL


              • #8
                I was told that the issue with copper is that mercaptin (the ingredient added to create the odor so leaks are obvious) would attack copper.
                Sounds like BS to me. Mercaptans have been used to "flavor" propane since forever and there isn't any problem with the copper tubing used with propane.
                Free software for calculating bolt circles and similar: Click Here


                • #9
                  Last few installs we've made were using this:


                  Seems to resist crushing better than copper and is cheaper.
                  I use black pipe where it's exposed, no code for that here that I've run into, just like having a stronger material in places it could get hit or have something dropped on it.



                  • #10
                    I have the abbreviated version of the International Fuel Gas Code that is included in the IRC. According to the good book:

                    Copper and brass tubing shall not be used if the gas contains more than an average of
                    0.3 grains of hydrogen sulfide per 100 standard cubic feet of gas.

                    I also have the tables that you are after in regards to flow, length and pipe size.
                    I will scan them later and send them to you.



                    • #11
                      Thanks again everyone. I tore into the box and dug out the instructions. They seem to indicate 1/2" but don't say how long the run can be. I think I'll be safe at only a 50 foot run. I know 1/2 will work for the propane but I'm hoping it will also work for the Nat Gas in a year or two when I can afford to have the lines run.

                      The drop tube and the on/off valve are both mentioned in the instructions so I will use them. I'm concerned with throwing out a red flag to the insurance company if some unfortunate development happened along. Hate to be paying for coverage only to not get it "if" ever needed.

                      The furnace is very "manly" I'm hoping that because it is electronic ignition that I can power up the 120 volt system with an rf remote control switch I already have from the house and have the furnace come on before I go out to the shop. Life would be good if I could pull that off !!

                      I think I'm all set now. I'll go 1/2" refrigeration copper to the black iron setup right at the furnace from the on/off valve to the drop tube to the furnace. This puppy weighs 80 lbs so getting it up on the ceiling by myself might require some creative use of my engine hoist.
                      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
                      Thank you to our families of soldiers, many of whom have given so much more then the rest of us for the Freedom we enjoy.

                      It is true, there is nothing free about freedom, don't be so quick to give it away.


                      • #12
                        Good luck getting your heater up where it goes I slid my hanging 125k BTU heater up a ladder onto the mezzanine above which it is hung (with some help). I then used an ATV jack to lift it into position while I attached the threaded rod that hangs it.

                        As for the corrosion of copper in a gas environment, I found this study via Google search:

                        The article had much to say and concluded that the stuff would not perferate in the 20 year service life they estimate. Better add "replace copper tubing" to your calendar for 20 years from today They did, however, mention the flaking problem. Their comments about pitting not being deep enough to cause perferation in 20 years would make me question the use of thinner tubing. Of course, I already stated that I would not be happy with copper tubing turning my shop into a bomb and I think the point about your insurance company questioning your wisdom is a good one. They might point out that a plumber would have used iron pipe and send you a "Dear John" letter. The irreplacable tools and stuff inside are worth more than the time savings to me. Here is an excerpt from the study:

                        "It was clear that bare copper tubing was susceptible to corrosion when exposed to distribution gas in the Pico Rivera service area. Corrosion products formed on the surface were friable and easily broke away from tubing wall. The amount of corrosion products trapped in the filter downstream did not clog or restrict gas flow. Nonetheless, the quantity of corrosion products generated in the foot-long sample did not represent the actual amount that could form in a typical house line. With longer lengths of bare copper tubing, as would be installed in a typical system, it is likely that a greater quantity of corrosion products would form and be available for transport downstream through the piping system. Based on the scope and results of this testing, it is not possible to project
                        the quantity of corrosion products and the potential to cause blockage at orifices in valves, regulators, etc. It is inconclusive that increases in the production of corrosion products due to longer lengths would actually lead to downstream blockage problems because the average size, consistency, and strength of these friable products were not determined. In most cases, the friable products were brittle and tended to break down into
                        smaller pieces as it dislodged from the tubing wall."
                        Paul Carpenter
                        Mapleton, IL


                        • #13
                          Don't want to throw a monkey wrench in this, but "refrigeration grade" has two
                          First, it is cleaned and sealed (folded) at the factory, so no dirt will be inside, which would plug a metering jet..thats OK
                          Second,it is fully annealed AND it is usually THINNER wall tube for ease of bending !


                          • #14
                            I just went and gave that report a quick scan again to see if they gave an initial wall thickness. They do. Its .050" so perhaps that will help with determining whether refrigeration tubing is adequate or not. They also indicate that their "end of service life" was the point at which corrosion had rendered portions of the wall thickness to be 80% of original.

                            It'd sure be a shame to use a bunch of tubing that you later found out was the thickness of tubing considered to be end of life!

                            Paul Carpenter
                            Mapleton, IL


                            • #15
                              I ran the Propane line for my wall hung Shop heater out of 1/2" Copper encased in 3/4 PVC pipe to protect it from rocks. It's been one the job for about 5 years with no problems---yet!