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  1. tomecki

    Slip-on Flange to pipe engagement code requirement

    Figure 127.4.4-2 in B31.1 does NOT show the setback. It only gives the size of the fillet weld.
  2. tomecki

    Slip-on Flange to pipe engagement code requirement

    I'm looking for a code requirement for how much pipe engagement is necessary on a slip-on flange. I know the industry practice is to leave 1/8" -1/4" from the face of the flange to the internal fillet weld, but I need something authoritative in a code or standard to point to. Unfortunately B31.1...
  3. tomecki

    ASME B31.4 Ch XI Operating vs Design Pressure ambiguity with respect to hydrotest requirements

    ASME B31.4 C437.4.1(a) "Portions of piping systems to be operated at hoop stress of more than 20% of the specified minimum yield strength of the pipe shall be subjected at any point to a hydrostatic proof test equivalent to not less than 1.1 times the internal design pressure at that point.."...
  4. tomecki

    HDPE conduit and cable thermal expansion issues

    I'm looking at an application where some power and fiber optic cables are installed in HDPE conduit. Total length and ambient temperature fluctuation is such that the conduit will expand and contract by up to +/- 5m (15 ft). The cables inside will expand and contract at a much lower rate...
  5. tomecki

    HDPE Pipeline Pressure De-rating due to Solar Heating

    I'm working on an a 36" DR9 HDPE pipeline to carry warm (30 deg C) water. The pressure rating of the pipe is sufficient at 30 degrees, however I'm concerned about further heating of the pipe due to solar radiation. The Plastic Pipe Institute HDPE handbook says that the surface temperature of...
  6. tomecki

    Inflatable Rubber Seal Design References

    I'm looking for any references on how to analyze and design an inflatable seal. The seal will be an inflatable rubber ring that will be located in an outer groove of a disc which is to seal against the internal diameter of a pipe. In my research so far I've found many companies that do custom...
  7. tomecki

    Inflatable Seal Design References

    I'm looking for any references on how to analyze and design an inflatable seal. The seal will be an inflatable rubber ring that will be located in an outer groove of a disc which is to seal against the internal diameter of a pipe. In my research so far I've found many companies that do custom...
  8. tomecki

    Force required to lift one end of infinitely long beam

    WOW! I just came back to this thread after moving on to something else for a while. Thanks everyone for contributing. I thought it was an interesting problem too, but I had no idea it would generate so much discussion. Might be a good one for a physics contest - simple question, takes a lot of...
  9. tomecki

    Force required to lift one end of infinitely long beam

    Thanks for the suggestions. I assumed that F = 1/2 weight of pipe of length l. Then solved for l using beam formulas. I did one calc using the cantilever beam model and one using the simply supported beam model. The moment in the pipe at the location where it lifts off the ground must be...
  10. tomecki

    Force required to lift one end of infinitely long beam

    I'm trying to figure out the force required to lift up one end of a long pipe by 2m. The pipe is long enough that the entire length of it will not lift off the ground. It will bend under it's own weight and become tangent with the ground at some unknown point away from the end. I tried to...
  11. tomecki

    PVC - Solvent Cemented Joint Strength / Failure Modes

    Thanks BigInch. So, in practice, would you expect to see the joint failure modes you describe to occur in a properly cemented joint at a much lower load than pipe failure? For example, in a welded steel or fused HDPE pipe, I would expect the joints to handle as much, or close to the load...
  12. tomecki

    PVC - Solvent Cemented Joint Strength / Failure Modes

    I'm investigating some joint failures in a 10" diameter, Sch 80, PVC pressure piping system. The pipe sections and fittings are joined by solvent cementing. This is a new installation and many leaks showed up during a pressure test. All the leaks are from cemented joints - from between the...
  13. tomecki

    Chemical cleaning of Alum scale from water treatment piping

    Thanks for trying to help but I'm not sure what to make of your response. I'm a mechanical engineer and my knowledge of chemistry is insufficient to make sense of what you're trying to say. As I mentioned before, neither Hydrochloric Acid nor Sulfuric Acid dissolved the scale in the lab. Do...
  14. tomecki

    Chemical cleaning of Alum scale from water treatment piping

    I have found the answer to part of my original question regarding the use of cleaning chemicals: NSF-60 says that anything that comes in contact with piping or equipment that will later come in contact with drinking water has to be NSF approved. When it comes to cleaning chemicals, they're...
  15. tomecki

    Chemical cleaning of Alum scale from water treatment piping

    Our water treatment flocculant supply line is severely scaled up with what is believed to be Calcium Sulfate scale, thought to have formed while the plant used Alum (We have made the switch to PACl since.) Lab test have been performed on the scale, and Methanesulfonic Acid and Green Liquor...
  16. tomecki

    Pipe stress analysis and buckling

    Thanks! I will look into the buckling on the compression side. As for the other loads mentioned: - there is no water load because the arrangement is such that the water level on the inside and outside of the pipe is always equal - vibration due to water movement - the clarifier is a settling...
  17. tomecki

    Pipe stress analysis and buckling

    I forgot to mention the pipe sees no pressure or vacuum.
  18. tomecki

    Pipe stress analysis and buckling

    I'm looking at installing some pipes in a water treatment clarifier. The pipes are 16" diameter and 60' long. They will be horizontal and simply supported at either end. The pipes never carry any additional static loading besides their own weight. The results of simple beam stress...

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