Not logged inAmerican Welding Society Forum
Forum AWS Website Help Search Login
Up Topic Welding Industry / Inspection & Qualification / Ir-192 limits
- - By raptor34 (**) Date 09-12-2009 09:34
I have some 18" sch 160 that a customer wants me to shoot with Ir-192, the pipe is not accessable from the inside and being that it is 3.562'' thick with out reinforcement, do I have a leg to stand on asking to shoot it with cobalt? also, will the film be readable if it is shot with Ir-192? If i remember right iridium is only effective up to 3". The code is api-1104 20th.
Parent - By CWI555 (*****) Date 09-12-2009 11:25 Edited 09-12-2009 11:36
3.562 without reinforcement.... I don't see it happening.
Parent - - By Joseph P. Kane (****) Date 09-13-2009 00:17
Raptor

Why would anyone purporting to be an RSO, or even a radiographer even ask such a question?!?!??????

Joe Kane
Parent - - By raptor34 (**) Date 09-13-2009 15:53
Joe,
Two reasons why i would ask such a question. First, depending on were you read you come up with several different effective ranges for ir-192. One source I have read says 3", another says 4", the chart above says about 2.5". My shot calculator goes up to four inches. Second, It is extemely time consuming and costly to get a cobalt source. not to mention the entire facility would need to be evacuated due to the locations of the welds. Gas companies dont take it very well when you put the control room inside your barricade. Yes is gives me a 5 minute shot compared to an hour with ir-192, but the company that shot the weld the first time did so with ir-192. I looked at the film and it is good quality film, the only problem is that it was shot to b31.3, and it needs to be reshot to 1104. And who said anything about being an rso?
Parent - - By Shane Feder (****) Date 09-14-2009 02:52
Raptor34,
What do you mean shot to B31.3 and needs to be reshot to 1104 ?
I don't understand, if it was interpreted to B31.3 and you still have the films why do you not just reinterpret to API 1104.?
Regards,
Shane
Parent - By spots (**) Date 09-14-2009 11:58
I am not familiar with API 1104, but AWS D1.1 limits Iridium 192 to 2 1/2" (6.17.6) anything thicker is to be shot with cobalt unless the Engineer approves something else.

D1.1 allows X-ray tubes up to 600 kVp without thickness limitations. It has been a while since I have worked with X-ray tubes, but that might be a viable option rather than the hassle of a cobalt source.
Parent - - By raptor34 (**) Date 09-14-2009 15:24
B31.3 allows for hole type pentrameters, 1104 does not, unless there is a geometric reason why wires cannot be used, then you are required to use an 1104 type hole pentrameter. 1104 also requires views of 5 inches or more to have 2 pentrameters were as B31.3 only requires one. The film is in lousiana and the pipe in in wyoming. And probably the most important reason is that DOT said no.
Parent - By CWI555 (*****) Date 09-14-2009 15:45
Dunno where you got the hole type requirement. 11.1.4/.5 of API 1104:05 states Either ASTM 747 wires, or ISO 1027 wires.
If this weld was shot in a manner not consistent with the end user code (1104) Someone really screwed the pooch on the front side.
Parent - - By ndeguy (*) Date 09-16-2009 08:36
raptor34

The logical original radiographic set-up would have been panoramic with the penetrated thickness (not including reinforcement) of 3.562", i.e. right at the limit for Iridium-192. Your customer should be made aware that this cannot be reproduced, only a double wall shot is possible and that Iridium-192 will not penetrate 7.124" of steel. If they (understandably) dont want to use Cobalt 60, then ultrasonics is the way forward. API 1104 allows ultrasonics and the 3.562" wall thickness is ideal for either TOFD or Phased Array inspection.
Parent - - By Bill M (***) Date 09-17-2009 20:44
18" sched 180 pipe has a w.t. of 1.78".  3.56" is the total double wall thickness to shoot thru  (i.e. 2 x w.t.)
Parent - By ndeguy (*) Date 09-17-2009 23:03
Thanks for the correction, Bill. I should have considered the 18" sch 160 part of raptor's OP.
Parent - By Atorroja Date 10-02-2009 11:00
Hi, for this thickness  (Double wall thecnique)Ir 192  or Co 60 shows poor resolution. Better if you go to ASME V Apendix 3 (TOFD). The cost is very close, maybe less, than Co 60 and this NDT is not dangerus.
Also, if the joint is not welded yet, you can shoot with IR 192 the half seam weld, and after the complete weld
Up Topic Welding Industry / Inspection & Qualification / Ir-192 limits

Powered by mwForum 2.29.2 © 1999-2013 Markus Wichitill