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  1. Andrew ONeill

    Stairway forces on Shell

    Spiral starcases likely have low loads, However it is quite common in chemical plants to support large structures, platforms, pipe supports off the sides of tanks. At the end of the day, the analysis method is usually borrowed from the pressure vessel world, and the resources like what HTURKAK...
  2. Andrew ONeill

    Surge Protection

    a) they work as designed, but tend to leak after a little while in service, if it's critical you have no leaks, I'd avoid it. If your operating pressure is close to the opening set point, tend to leak even more. b) don't know what this is. c) regarding a & maybe b, usually these help to treat...
  3. Andrew ONeill

    750 AUD per year for Engineer Australia membership. Is it a joke?

    My 2 Cents. Having lived and breathed it in QLD (QLD has had a professional engineers Act for about 100 years). - CPeng (Engineers Australia) is not mandatory, but people see it has a defacto badge to indicate competence in the absence of any legislation (in litigation lawyers could argue it's...
  4. Andrew ONeill

    Minimum required thickness for PAUT for process piping

    Rule of thumb is around 6-8mm as the minimum for any form of ultrasonic crack testing (PAUT is just a fancy version of UT). However, if someone does qualification testing on sample plates, and all the stuff that does with it, that value may be able to be reduced on a case by case basis. I've...
  5. Andrew ONeill

    Ladder Safety Systems

    I don't have direct experience, and I'm a mechanical engineer, not structural. I cna't answer Q1 and 2, but here are my thoughts on Q3. It would be worth checking if the rating of the system is based on Testing vs Calculations. Actual loads via testing are likely to be significantly different...
  6. Andrew ONeill

    Tank Settlement Survey

    My typical experience is an operating facility would survey every 5-10 years, but do it as a whole site survey, typically there will be other structures (e.g. stacks) or large buildings or strain critical equipment where some sort of survey is also a good idea. Normally just group it into that...
  7. Andrew ONeill

    Hydrogen Embrittlement ASTM A574

    I once had to deal with a significant stress corrosion cracking failure of B7 studs. These looks similar, but in reality, to know anything is to send them away for testing. In saying that I learnt 2 super important factors in relation to fastener manufacturing, that are not obvious, and are...
  8. Andrew ONeill

    When would piping need to be replaced due to an overpressure event where the Yield Stress was exceeded?

    Assuming plain old carbon steel piping and assuming the fluid doesn't cause some sort of weird corrosion mechanism related to the steel yielding, I'd say do a visual, if nothing obvious, leave it alone. I'd be more worried about crack like flaws, but again is the piping it "hot" that's probably...
  9. Andrew ONeill

    Spacing Between Openings on Pipe Circumference – Limitations?

    only other comment to add is how easy it is to construct; the welder might not be too happy about trying to get an electrode into a crevice and somehow make a compliant but weld with a mirror and an electrode bent at 70deg to fit... I'd always run something like this past a welder to make sure...
  10. Andrew ONeill

    iAlert3 replacement recommendations

    I've seen the Emerson product deployed, works well, but cost is likely higher than the i-alert system. https://www.emerson.com/en-au/automation/asset-performance-management/asset-monitoring/condition-monitoring/online-condition-monitoring-mechanical-assets There is probably half a dozen...
  11. Andrew ONeill

    Inadequate PWHT holding time for Carbon Steel piping in caustic service (NACE SP-0403)

    I guess there are 2 issues here, 1) Contract acceptance 2) Plant performance., but I'll preface this with a few points A) From my experience with CSCC -> It's not an exact science, the NACE curves should be considered guidelines with quite wide bands. Depending on the fluid and other...
  12. Andrew ONeill

    Very High Temperature Piping Stresses

    I did something for a trial in a furnace once ~ 1100 C. Still used B31.3 / 31.1 principles, but 1) Tracked down material properties at that temp, and used the Su/3, Sy/1.5 criteria to determine an allowable stress 2) Looked at creep data (in my case was short term service (days to weeks for...
  13. Andrew ONeill

    Techniques to enforce nearly uniform flow velocity in a rectangular duct

    Here's a random paper that describes it fairly well. https://www.flowconditioner.com/wp-content/uploads/2020/07/FFC-Whitepaper-3_CPA.pdf In practice there is a boundary layer, you will never get an equal velocity profile across the full cross-sectional area, however you can improve it /flatten...
  14. Andrew ONeill

    Pump Priming Instrumentation

    Hey everyone, Thanks for the replies.
  15. Andrew ONeill

    Pump Priming Instrumentation

    Hi Team, I went down a rabbit hole a little while ago about using instrumentation to prove a centrifugal pump is primed. Intent is to have interlocks or alarms to prevent dry running of said pump after a maintenance changeout and / or suction piping lineup changes. I'll note the question for...
  16. Andrew ONeill

    Fan vibration and its effect on fasteners

    You're unlikely to be able to model this in any meaningful way. Unless the specific brand of thumbscrew supplier has completed testing to determine the allowable 5 year vibration level on a faster setup close to your proposal (which is highly unlikely). In practice, I'd suggest applying a...
  17. Andrew ONeill

    Scale consideration with ultrasonic wall thickness testing

    In my experience, not a problem, extensive experience with hard slurry like scales that form inside pipes, sometimes several inch's thick. This is assuming you are measuring from the outside. If you are measuring from the inside, it will be a problem.
  18. Andrew ONeill

    Centrifugal Pump - Priming

    I haven't seen a setup like this in practice, but I don't see it being any different to a vertical submersible pump, that is common in slurry process sumps where the entire volute is submerged for the same reason. I agree a foot valve is Maintenace nightmare in a slurry service and agree with...
  19. Andrew ONeill

    AS4041 Piping Design

    I just had a look, and I'm thinking that the Australian Commitee copied the formula wrong :S, I have come across that before in some obscure clauses. From a fundamental point of view, the basis of these calcs is that a pipe will try and "straighten out" when subject to internal pressure, and as...
  20. Andrew ONeill

    Transverse Cracking in Carbon steel welds

    I'd suggest also not to rule out product induced cracking. When I First read it, my mind when straight to stress corrosion cracking, which usually presents itself as traverse cracks, always initiating from the inside surface. In my industry this is a key damage mechanism, in particular from...

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