Definition for RT?

qaqcmpm · **Joined:** Wed Sep 24, 2008 11:45 am **Posts:** 64

where I will get the definition for spot RT? I think One spot per welder for Long seam & T spot (junction between long seam & cir seam)? If the cir seam welded by another welder it requires RT?

Gonzaga · **Joined:** Sat Dec 15, 2001 1:00 am **Posts:** 657

qaqcmpm wrote:

where I will get the definition for spot RT? I think One spot per welder for Long seam & T spot (junction between long seam & cir seam)? If the cir seam welded by another welder it requires RT?

You don't need to RT weld crossing. You need to RT each welder.
Read UW-11(b) and UW-52:
One film (6 in = 150 mm long) every 15 meters of weld produced by the same welder, on full penetration but welds (radiographable). Welds in nozzle and communication chambers are exempt when do not exceed neither NPS 10 nor 1.1/8 in (29 mm) weld thickness. The location of the spot shall be chosen by the Inspector after the weld is completed.
Mauro

qaqcmpm · **Joined:** Wed Sep 24, 2008 11:45 am **Posts:** 64

Thanks for your reply. But UW 52 (4) states that

Code:

Radiographs required at specific locations to satisfy the rules of other paragraphs, such as UW-9(d), UW-11(a)(5)(b), and UW-14(b), shall not be used to satisfy the requirements for spot radiography.

When I refer UW-9 (d) if the long seam is not separated by 5 times thickness of the thicker plate, 4in length of Cir seam (both the sides) required to be radiographed.
UW 9(d)

Code:

Except when the longitudinal joints are radiographed 4 in. (100 mm) each side of each circumferential welded intersection, vessels made up of two or more courses shall have the centers of the welded longitudinal joints of adjacent courses staggered or separated by a distance of at least five times the thickness of the thicker plate.

So in this case is it mandatory to spot RT the Cir seam additionally.
And as per UW 11(a)(5)(b) whenever category C & D butt welds intersect category A butt welds as a min requirement to spot RT. (but in your reply u have mentioned intersection-T is not required?)
UW 11(a)(5)(b)

Code:

Category B or C butt welds [but not including those in nozzles or communicating chambers except as required in (2) above] which intersect the Category A butt welds in vessel sections or heads or connect seamless vessel sections or heads shall, as a minimum, meet the requirements
for spot radiography in accordance with UW-52.

And as per UW 14(b)

Code:

Single openings meeting the requirements given in UG-36(c)(3) may be located in head-to-shell or Category B or C butt welded joints, provided the weld meets the radiographic requirements in UW-51 for a length equal to three times the diameter of the opening with the center of the hole at midlength.

if the opening is Full pen BW + cover fillet can I use UT for UW 51 requirment?

Javed Nasir · **Posted:** Tue Jan 11, 2011 9:28 pm

Dear Mauro,

You said,
"The location of the spot shall be chosen by the Inspector after the weld is completed."
Unquote:
The location of the spot shall be chosen by AI, but when AI is not avaiable and he is notified in advance by the Manufacturer about the spot selection, in this case Manufacturer may exercise his own judgement in selecting the spot(s) as per last sentence of UW-52(b)(3).
When AI is sured not to be present at the time of selection of the spot, spot selection can even be made before starting the welding if AI is agreed with Manufacturer, please see Interpretation VIII-1-95-87.
Please correct me If I am going wrong.

Gonzaga · **Joined:** Sat Dec 15, 2001 1:00 am **Posts:** 657

Javed Nasir wrote:

Dear Mauro,

You said,
"The location of the spot shall be chosen by the Inspector after the weld is completed."
Unquote:
The location of the spot shall be chosen by AI, but when AI is not avaiable and he is notified in advance by the Manufacturer about the spot selection, in this case Manufacturer may exercise his own judgement in selecting the spot(s) as per last sentence of UW-52(b)(3).
When AI is sured not to be present at the time of selection of the spot, spot selection can even be made before starting the welding if AI is agreed with Manufacturer, please see Interpretation VIII-1-95-87.
Please correct me If I am going wrong.

Correct. I wanted to be short. The basic is that the AI shall agree. I do not have the interpretation. I presume the welder should not be advised of the location of the Spot RT. :wink:

Javed Nasir · **Posted:** Sun Jan 16, 2011 10:57 am

Yes, logically welder shall never be known in advance about the location of spot otherwise statistical approach of UW-52 may not work properly that is refelected from the Note prior to opening the body text of UW-52.Here is that interpretation, Manufacturer in cases when AI cannot be present may know himeself in advance the location of spot because utlimately he owns the responsibility of workmanship.

Interpretation: VIII-1-95-87
Subject: Section VIII, Division 1 (1995 Edition); UW-52(b)(3)
Date Issued: December 28, 1995
File Number: BC95-463

Question: Would the requirements of UW-52(b)(3) of Section VIII, Division 1 be met if the location for performing a spot examination is chosen in agreement with the Authorized Inspector prior to the start of welding when the Authorized Inspector cannot be present after the welding increment is made?

Reply: Yes.

Definition for RT?

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