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Recent content by gwalkerb

  1. gwalkerb

    Butt weld fittings

    Assuming this is a ASME B16.9 fitting, you can check the allowable tolerances from that standard (Table 11-1). Between NPS5 and NPS8, the tolerance on outside diameter is +0.09"/-0.06", while the tolerance on inside diameter is +/-0.06". Nominal outside diameter for NPS6 is 6.625". With...
  2. gwalkerb

    Thermowell for small size pipes

    It very much depends on the application. If the restriction to flow created by the thermowell in an NPS2 pipe is not a concern, then you don't need to do any size changes. If it is a concern, going up to 6" seems pretty excessive, I wouldn't see a need to go any bigger than NPS3 or NPS4. You...
  3. gwalkerb

    B31.12 Preheat Requirement Conflict

    To me it looks like they updated Table GR-3.5-1 but missed the inconsistency with section GR-3.4 (d). You could contact ASME yourself to find out the answer, and in the meantime, just use 16C as your minimum allowable preheat temperature. Both locations define the temperatures as a minimum...
  4. gwalkerb

    Spiral wound gaskets for use with flat face flanges

    LittleInch, how are you reading Table B-1 as prohibiting this usage? A spiral wound gasket falls into group Ib, but those gasket categories aren't used anywhere else. Following the references in Appendix B, it takes us back to B16.5 5.4, and 5.4.1 states that 'The user is responsible for...
  5. gwalkerb

    Opinions / Facts - New Small-Bore Valves installed into existing "tested" piping assemblie

    If you're in Alberta, ABSA has weighed in on the requirements for leak testing of valves. https://www.absa.ca/media/2272/ib21-005-leak-testing-components-asme-b313.pdf If you're not in Alberta, this at least gives you one organization's interpretation of the testing requirements.
  6. gwalkerb

    Welding of A193 B7 material

    There's not an explicit clause that says 'Though shalt not weld A/SA-193 Gr B7'. However, take a look at QW-421.1 in Section IX. SA-193 Gr B7 is not listed in table QW/QB-422. To treat it as an unlisted material, you would need to have an equivalent UNS designation. SA-193 does not list a...
  7. gwalkerb

    Process and Non Process Difference

    As far as I know, there's not a code or standard that explicitly defines process vs non-process or utility. Since different requirements may apply to systems that are considered part of the process vs not, it's always best to confirm the definition with whomever is responsible. I've had...
  8. gwalkerb

    Specific Heat Capacity & final temperature of a mixture of ideal gases

    I was looking at calculating this value for mixtures of gases (treated as ideal gases). Some resources I've found online suggest taking the mole fraction of each constituent gas and multiplying that by the specific heat capacity, and then taking the sum. i.e. Cpmix=Σ(ni)(Cpi) However, since...
  9. gwalkerb

    ASME B16.20 Table RJ-3.2-1 Maximum Hardness

    In this table, the first two materials listed are Soft Iron, with a maximum hardness of 90 Brinell or 56 Rockwell "B", and low-carbon steel, with a maximum hardness of 120 Brinell and 58 Rockwell "B". However, Note 1 is referenced for the soft iron, and states 'May be low-carbon steel, not to...
  10. gwalkerb

    B31.8 Hoop Stress Calculations with MSS SP-75 / ASTM A860 fittings or MSS SP-44 / ASTM A694 flanges

    Thanks to both of you. GBT: I did go back and look at some of the historical versions of 5L and B31.8 to get some context. The latest version is edition 46 (2018), which is a little ambiguous, as it states that the SMYS would match the numerical portion of the material grade (i.e. X60 =...
  11. gwalkerb

    B31.8 Hoop Stress Calculations with MSS SP-75 / ASTM A860 fittings or MSS SP-44 / ASTM A694 flanges

    I have two questions related to interpretation of certain B31.8 sections. We build compressor packages, usually to B31.3, and so we use a lot of ASME B16.9 fittings and B16.5 flanges. We've been building to B31.8 for some packages these days, and there's a minor ambiguity I want to confirm...
  12. gwalkerb

    A420 Gr WPL6 impact test temperature documentation & unit systems

    Thanks everyone. The MTRs are technically non-compliant as they don't specify values in both unit systems, but they do specify both the USC and SI material specs. The customer agreed to rate the piping system to -49F to avoid any issues. Overall, I agree that this was a bit silly, but...
  13. gwalkerb

    A420 Gr WPL6 impact test temperature documentation & unit systems

    We are building ASME B31.3 piping for a compressor package where our customer has specified an MDMT of -50F for certain outdoor applications. We are using the typical materials A333 Gr 6, A420 Gr WPL6, and A350 Gr LF2 Class 1 for this system. Our QC department has raised a concern as the MTRs...
  14. gwalkerb

    Class A, B, C shutdown logic

    Have you tried asking one of those vendors if there's a code basis, or if it's one of their own internal standards?
  15. gwalkerb

    Hoop Shrinkage on B31.3 Stainless Piping

    I don't know if I would agree with this statement. > all material remains in its intended, unmodified and purchased condition post welding. The details from A999/A999M Table 1 are for the material in its as-delivered state, it's not intended as permissible variations to the material after any...
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