07:58 Jun-06-2007 Nigel Armstrong Engineering, - Specialist services United Kingdom, Joined Oct 2000 1094
ASME ultrasonic calibration blocks
The attached link is to an US company (Ray-Check) offering a set of alternative ASME calibration blocks manufactured in accordance with the Performance Demonstration Initiative (PDI), PDI-UT-1, Rev C (ferritic) and PD-UT-2, Rev C (austenitic).
A previous thread on ndt.net demonstrated the increased(unmanageable?) range of pipe calibration blocks required since the 2002 issue where Article 4 became Ultrasonic Examination of Welds:
Ray-Check claim: "These cover the generic procedures for the ultrasonic examination of both ferritic and austenitic pipe welds. The blocks offer an economical alternative to fabricating multiple curved calibration blocks (pipe sections) in numerous diameters and wall thicknesses."
How can a set of 3 blocks (ferritic, 304 and 316 I believe) replace all those pipe nominal sizes and schedules supposedly required by T-434.3. I realise ASME is a pressure vessel rather than a piping code but unfortunately the piping codes (B31.3 and B31.4) specify use of ASME V and I can see no word in that document alowing use of these notched blocks. Even B31.3 Code Case 181 and ASME V Code Case 2235-9 require the manufacture of a qualification block of "the same product form, and material specification or equivalent P-Number grouping as one of the materials being examined. Has anyone experience with these "alternative blocks" iaw the PDI. Was this PDI run at EPRI? Why is there no mention of it in updates to ASME, how is anybody going ot learn about it apart from As our German colleagues say "reine Zufall".
I would be grateful for any enlightenment anybody can offer.
Re: ASME ultrasonic calibration blocksIn Reply to Nigel Armstrong at 07:58 Jun-06-2007 (Opening).
I am hoping to revive this post and see if anyone out there has any insight on these blocks. I have not been able to find any ASME code cases that allow for the direct use of these. Also, where can you find the full PDI-UT-1, and -2? I have contacted a few of the manufacturers that are selling these blocks for more information and have not received any response back on. Any feedback would be appreciated. I also know that if I was to qualify these blocks individually on a job by job basis that they would be allowed, but I am trying to save time and money, so I am really looking for any documents that will allow the direct use of these alternative blocks. http://www.flawtech.com/proddetail.asp?prod=PDI-CB-4 Thanks everyone.
The short answer would be no, these blocks would not be allowed according to code. For stainless steels not only should you have cal blocks of the same diameter/thickness of piece to be inspected.
You should also be demonstrating the system capabilities on a specimen welded according to the WPS used on the specific project.
Thanks for the feedback. I thought these were too good to be true. However, I would love to see these PDI-UT-1 & 2 procedures to see what they are all about. What I don't understand is if the nuclear world (NRC and EPRI) have approved these through the performance demonstration initiative, why has ASME not made a code case about them. Nuclear inspections are to ASME section XI so if they are using these how are they not approved for regular ASME section V work of the same type (pipe butt welds). Also, if they are in use how is there not a code case about them? How are these companies getting away with selling these as an alternative to the standard ASME piping calibration blocks we all love so much. Has anyone seen these in use or know anyone that has used them? Still curious and hoping someone can provide more information on these. Thanks again.
Since Nigel posted this item in 2007 until now there has been a change in ASME Section V. In 2010 the paragraph T-434.3 Piping Calibration Blocks; describes how the basic calibration block configuration and reflectors shall be as shown in Fig. T-434.3.
But then departs from the old requirements to match schedule and allows curvature in accordance with T-434.1.7 and thickness ±25% of the nominal thickness of the component.
In a general way I echo John's statement about SHALL, however, ASME's statements concerning "shall" do not always mean mandatory. For example, T-434.4.1 states that the basic calibration blocks SHALL be as shown in Fig. T-434.4.1. Then in the very next paragraph T-434.4.2 provides for an alternative block. It is difficult to understand the term SHALL in the normal way that standards are written when it is accompanied by the concept of "or". This is seen in a few places in Section V. E.g. T-434.1.1 specified reflectors "SHALL" be used. Then in the next sentence they allow that an alternative be used.