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.
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...
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...
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.
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...
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...
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...
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".
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...
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?
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?
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.
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...
There should be limits placed on the fill rates based upon type of roof (steel, aluminum) and the low-leg setting. Filling too fast can cause product to splash through wells in the roof and onto the deck plate. Typically it is recommended to fill the tank slower initially until it is floating...
I posed this question similar to this at an ASCE seminar last year. The lecturer kindly responded that (to paraphrase)EFR tanks are a bad idea in highly seismic regions. Unfortunately for those of us in the industry that is not an option. API doesn't appear to address this specific issue...
Joe Tank,
Thanks for the response, however I can't say that I agree that 9.2.3.3 applies to this situation. That section is for replacement shell plates and the offset of such plates from bottom weld seams. In this case the shell is not being modified at all, only the bottom is being replaced...
I can't find anything in API650 or 653 that discusses required offset between shell vert welds and bottom plate lap welds. Specifically, regarding a bottom replacement. I have always tried to use 12" when designing and detailing new construction, and this was just a rule-of-thumb that someone...
You may be able to install external structure to support the mixer loads. The structure would have to be tied into vertical supports off the shell plate. The design and analysis for this option could get pretty involved and would likely require an FEA. The flat roof option may be easier/cheaper.
