API 650 Annular Plate Function
API 650 Annular Plate Function
(OP)
Will someone please tell me what is the exact function the annular ring under the tank shell. According to API 650 sect 5.5 an annular ring is soley dependant on the stress in the bottom course. According to BS 2654 a tank over 12.5m dia must have an annular ring. I would like to know why the annular is necessary? Because butt welded the completely flat and even surface makes the shell to bottom weld much stronger but there must be more. Please assist.





RE: API 650 Annular Plate Function
Joe Tank
RE: API 650 Annular Plate Function
RE: API 650 Annular Plate Function
Why would you than ever have annulars the same thickness as the bottom should the stress not exceed the parameters set out in 5.5.3. For example if you have a bottom course of , 19mm and a stress < 220 the annular plates are 6mm. How is this annular ring assisting in any way if the bottom plate is also 6mm.
RE: API 650 Annular Plate Function
Joe Tank