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Recent content by TankDude

  1. TankDude

    API-650 Table 5-21b

    If memory serves, these changes were due to mistakes discovered in the S.I. table. The calculated values were not consistent with those calculated using the formulas in the Imperial table. You may be able to verify this by performing some sample calcs from the two addenda.
  2. TankDude

    API-650, Appendix R, Equation (g)

    gdubyuh, IF you connect your IFR cables to the bottom flange of your fixed roof rafters, how do you adjust from high to low leg setting? Just curious. I agree with the method IFRs describes. In fact, I typically obtain the actual proposed layout from the IFR manufacturer to determine where...
  3. TankDude

    API Riveted Tank -- Repair of Horizontal and Vertical Seams

    Jeff, One common method is to use a butt-welded insert for the vertical seams and simply lap-weld the horizontal. I have used this detail and it has worked nicely. I utilized the basic rules for lap-welded tanks as discussed in the old Process Equipment Design text. Another detail that I have...
  4. TankDude

    API Standard 650 and 653 Sump Installation

    To my knowledge you will not find any stipulations regarding the position of the sump relative to bottom plate weld seams, however API-650 does provide recommendations for the location relative to the tank shell.
  5. TankDude

    Uplift from wind and Overturning - Anchorage

    A. I would recommend forgetting about the overturning moments initially. Simply determine the combined uplift pressure from wind and design internal pressure. This total value must be less than or equal to 1.6P with P being calculated per F.4.1 Therefore, you should use the combined uplift...
  6. TankDude

    The allowable stress for API 650/653?

    My advice would be to use API-653 allowables and apply the Appendix M reduction factors to these. As for why there are different values between 650 and 653, I don't know for a fact but my guess is that the reduction in allowable stress by 653 is meant to account for potential unknowns when...
  7. TankDude

    MDMT of A36 Plate

    You could be correct gdubyuh. Now that I have looked in the 11th Edition, it appears that this provision has been removed. It was Section 2.2.9.5 in Add. 4 of the 10th Edition. Section 2 became Section 4 in the 11th Edition, and there is no 4.4.9.5. Does anyone have any input on this? Is it...
  8. TankDude

    MDMT of A36 Plate

    If the MDMT is specified or shown on Fig. 4-2 as -20 Deg. F. then you can add 15 Deg. F to that, for a value of -5 Deg. F, at which (by my interpretation) A36M would work for thicknesses less than about 5/8".
  9. TankDude

    Low Nozzles Violating API-653 Weld Spacing

    In short the nozzles were installed using tombstone-style insert plates but the nozzle centerlines are below the minimum centerline specified by Table 5-6. As a result the minimum weld spacing dimension 'D' per Figure 5-6 has not been met. The tank has already been hydrotested and sits on a...
  10. TankDude

    Low Nozzles Violating API-653 Weld Spacing

    Does anyone have any advice regarding steps to take when evaluating new shell nozzles that have been installed in a tank and that do not meet current API-653 weld spacing criteria?
  11. TankDude

    Column Load Distribution in API 650 11th Edition

    It is not clearly stated that way but I would consider taking that approach to be conservative.
  12. TankDude

    API-650 Appendix E

    Check this link for the published Errata for the 11th Edition: http://www.api.org/Publications/addenda/upload/650_Ed10wAd4_Er1.pdf
  13. TankDude

    API-650 Scaffold Hitch

    To my knowledge API-650 doesn't provide a recommended max loading for the standard scaffold hitch. Before I jump into the process I was just wondering: has anyone ever taken the time to calculate it and if so what was the result?
  14. TankDude

    API 650 - Reinforcement plate for nozzles / manholes

    Reinforcement plates shall be of the same "nominal" composition per 5.7.2.3(b), meaning the same ASME P and Group number. This doesn't necessarily mean that they have to be the exact same material.
  15. TankDude

    Horizontal Projected Area - Defined

    Though it seems excessive, it is exactly what you are likely thinking: Pi x Horz.Radius^2 This appears to increase the overturning moment for most tank sizes, and can produce strange results depending upon tank diameter to height ratios. The key thing to note, I believe, is that there is a...

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