Part MAWP for the cylindrical shell calculation 3

[Mash18]

Hi All, please see the images below (Question and Solution). I am struggling to understand 2 things:

a. How do you determine that RT-2 = 0.75?, To be honest I really do not understand this in general. if someone could perhaps provide a basic step by step.

b. I also really do not understand where the 0.875 comes from with regard to the thickness.

Thanks in advance.

 

[r6155]

Why don't you read your example?
Why don't you read UG-16 (d)? : t-12.5% undertolerance = t x 0,875
Why don't you search for nameplate in ASME VIII Div.1?: UG-119 and UG-116

Do you have ASME VIII Div.1?

You should make minimal effort to search for data and understand it before asking for help.

Regards

 

[Soft2008]

@Mash18, seems you misunderstood.

a) E=1 is used(not 0.75). See the calculation step
Once you see references UG-116, UW-11 (1)(5)(-b) and Table UW-12 then you would understand the reason of E=1.
b) 0.875 multiplied to thickness (0.75")is because of UG-16 (d) pipe under tolerance of SA-106-B

 

[Mash18]

@Soft2008

Thank You, eventually took some time but I got the hang of it and I've figured it out, Thanks again!!

 

[r6155]

@ Soft2008
The (OP) is not a question about E=1 Now you are mentioned it.
Seems you misunderstood too.

1) UW-11 RADIOGRAPHIC AND ULTRASONIC EXAMINATION
UW-11 (a) (1) (5) (-b) is not a reason of E=1

2)The clear reason is in UW-12 JOINT EFFICIENCIES
(d) Seamless vessel sections or heads shall be considered
equivalent to welded parts of the same geometry
in which all Category A welds are Type No. 1. For calculations
involving circumferential stress in seamless vessel
sections or for thickness of seamless heads, E = 1.0 when
the spot radiography requirements of UW-11(a)(5)(-b)
are met.

Regards

 

[Soft2008]

@r6155,Now noticed table UW-12 noted in my last answer however missed the reference of UW-12 JOINT EFFICIENCIES (d) relating to seamless.

UW-12 JOINT EFFICIENCIES (d) states that E = 1.0 when the spot radiography requirements of UW-11(a)(5)(-b).
Its this same information I wanted to convey in previous post. Thanks for pointing the answer precisely in your post.