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# RT efficiency ?2

## RT efficiency ?

(OP)
i have a question about RT efficiency in preparing calculation sheet.

1) From datasheet, shell side is spot.
In calculation, if you use seamless head and rolled plate for shell.
what is E for shell?
what is E for seamless head?
So, What is the right one of RT-1, RT-2, RT-3 and RT-4 for stamping on the name plate?
in testing, How do i test on the welding line(In this case, there are long. seam and cirr. seam)?

2) From datasheet, shell side is spot.
In calculation, if you use seamless head and pipe for shell.
what is E for shell?
what is E for seamless head?
So, What is the right one of RT-1, RT-2, RT-3 and RT-4 for stamping on the name plate?
in testing, How do i test on the welding line(In this case, there is cirr. seam.?

### RE: RT efficiency ?

b5quaj,

As for the seamless head, E=1 in all calculations as there is no weld seam.

1. Nominal thickness
2. Lethal or non-lethal service
3. Weld joint category and type

2001 ASME Section VIII D.1 section UW-3 (page 116) lists the weld joint categories for pressure vessels; then flip over to page 120-121 (Table UW-12 for types of joint configuration.)

By using these two sections determine the proper joint efficiency based on degree of radiography performed.

As for stamping the nameplate, refer to UG-116 (page 88)para.(e)(1-4) for proper marking based on the radiography performed in accordance with UW-11. (it would appear that RT 2 is what you're after.)

Finally, on the subject of testing (the proper term is examination by the way...testing is usually the pressure test or other proof test.), section UW-52 on page 153 gives the requirements for spot radiography.

Normally, one spot on each long seam (per welder) and each circumferential seam to long. seam junction are selected as examination sites.

I hope this helps...

Richard Schram
Mechanical Integrity Specialist
Pharmacia Global Supply Arecibo-P. Rico
rschram@pharmacia.com

### RE: RT efficiency ?

In addition to using Table UW-12 it is important to read the paragraphs of section UW-12 applicable to the type of radiography/construction; eg: UW-12(a) for full RT and UW-12(d) for seamless.

Both paragraphs restrict the joint efficiency depending upon the radiography performed on joints intersecting the joint in question. Generally, the requirements of UW-11(a)(5)(b) must be met to justify E=1.0 for seams with full RT (or seamless), otherwise E=0.85.

Also, read carefully the definition of 'E' to be applied to the component. For example, UG-32 defines E for heads as based on the lowest for any seam in the head. But the head-to-shell seam in included only for hemispherical heads, not for semiellipsoidal or torispherical heads.

Tom

### RE: RT efficiency ?

Code of construction - ASME VIII, Div. 1

See Table UW-12 for the joint efficiencies required for your head to shell calculations.

1)
If you mean (spot) requirements of UW-52, E= 85% for  type 1 joints with a stamping of RT-3. See Table UW-12.

If you mean (spot) requirements of UW 11 (a)(5)(b) "Full Radiography" for the head to shell and that you have meet the "Spot Radiography" of UW 11(b)for the shell(Type 1 joint); E=100% for head to shell {See UW-12(d)} and E=85% for the shell.  The stamping requirement would be RT-4.

2)- assuming Type 1 joints and seamless to seamless
If no radiography is applied; read UW-12(d).  There would be no RT stamping.  Please note that the above (d) does not send you to Table UW-12 for E.
If UW-11(a)(5)(b) is applied the stamping would be RT-2.

Please be aware that both calculations in UG-27(c)(1) and
(2) are required.  UW12-(d) refers to circumferential stress only.

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