Variable Point Method

[Aombraz]

Dears,

I am trying unsuccessfully reproduce the example of thickness calculation thru the VPM (Variable Point Method) as shown on the reference book, Page 66 (CALC 001 / 001). On the third course, second trial, when applied the rule "K = tLt / ttu" I just found the value "1.157", instead of "1.128". I am quite curious to know where is my mistake and I will be glad by your help on solving this technical doubt.

Ref.: GUIDE TO STORAGE TANKS & EQUIPMENT- Bob Long and Bob Garner, Page 66.

Thanks

A.Moraes
aombraz@gmail.com

 

[JStephen]

The 1.128 looks to be 20.92/18.54, which I'm thinking, means they used the wrong lower course value there. Anyway, check how the terms are defined in API-650 and work accordingly. I think some of that has been changed up slightly through the years. You might check if there's an errata to that book, also.

 

[Aombraz]

Dear JStephen

I can not found an errata of this book until now and the "K" factor there seems to be one single mistake. Anyway, thanks by the clues.


A.Moraes
aombraz@gmail.com

 

[IFRs]

Have you tried to replicate the VDPM example in API 650 Annex K?

 

[Aombraz]

Thanks IFRs and JStephen by your advices: I will replicate the examples of API 650 Annex K. When changing the book's data, following the API rules, the remaining calculations seems to be fine.

A.Moraes
aombraz@gmail.com