Henry;
One thing for sure. It is NEVER a good idea to ask ASNT for their opinion whether an ASNT Level III is needed!!!!!
I was hoping to stay out of this string for a few more days, but it has taken some strange turns and perhaps it is time for my two cents. Remember, I am not a member of the D1.5 Committee and cannot give you an "Official" interpretation. If you send in a series of questions to the D 1.5 Committee, for an "Official Interpretation", it may take two years to get a reply.
Everyone must remember that D1.5, while it a National Code, is just a guidline to most State DOTs. Most States take several exceptions to it. New York State DOT has the New York State Steel Construction Manual, and currently does not use the D 1.5. The NYSSCM was the first "Bridge Code" and had the first "Fracture Critical" section. However, it is more than a Code, it is a "Construction Manual" that covers many aspects of bridge construction. (In my opinion, it is the best bridge fabrication document on the planet.) Under the NYSSCM, the MT, PT UT & RT personnel have to be qualified to SNT-TC-1A. The UT practitioner also has to pass a "hands on test" given by the NYSDOT in Albany. This is the "GOLD STANDARD" of UT tests for structural inspection.
Under D1.5, the NDT practitioners must be Qualified in accordance with ASNT SNT-TC-1A and the Level III "Supervisor" can be Qualified and Centrally Certified (by ASNT), or Qualified in accordance with SNT-TC-1A. The practitioner must be qualified differently, depending on whether the product is Non-FCM bridge fabrication (Section 6), or "Fracture Critical" (FCM) fabrication (Section 12). The rules are stricter if you are doing Fracture Critical inspection. T(here is an explanation in the Commentary section (C12.16.2.1). The last sentence defines what is meant by Level III "Supervision". In my opinion it was intentionally left this vague, to address the operational requirements of the various State DOTs.)
For normal fabrication (Non-FCM), the qualification requirement (Paragraph 6.1.3.4), has wording that says the Certification of Level I and Level II personnel shall be performed by a person Certified by ASNT or by "testing" under the provisions of SNT-TC-1A. The individual who performs the NDT must be qualified for NDT Level II or NDT Level I, working under the direct supervision of an individual qualified for NDT Level II. There is no routine supervision requirement for the "performance" of NDT operations for Non-FCM fabrication. NOTE! The Qualification and Certification operation is different from the "performance" operation requirements.
For "Fracture Critical" fabrication, NDT may only be performed by a person qualified to Level II or Level III in accordance with SNT-TC-1A, and MUST be "supervised" by a person who has a current ASNT Level III Certificate. (The Engineer may approve an equivalent alternate qualification, and most State DOTs use this exception for their third party inspectors.)
Note; Not all Level III personnel are qualified to actually perform (practice) the NDT operations. Thus, the wording that the Level II and Level III practitioners must be qualified to SNT-TC-1A, means that the Level III "practitioner" must also take the Level II examination. The Level III "Supervisor" must be centrally certified by ASNT, unless the exception is made by the Engineer.
I know that "supervision" under the FCM provisions of D1.5 are not the same as the "supervision" requirements under the QC-1 for the CAWI. The Level III does not have to be in "visible and audible range" of the Level II at all times. (This is explained in the commentary)
Besides all this, the company that performs FCM has to have an approved QA Manual, and if they fabricate FCM, an "Approved" FCM Manual. Thus, the requirements vary from company to company, and depends on what their DOT clients will approve. Most fabricators modify their QA Manuals and FCM Manuals to satisfy their DOT clients.
Joe Kane
"Everyone must remember that D1.5, while it a National Code, is just a guidline to most State DOTs."
I have to disagree with this. Taking a couple of exceptions to the code does not mean the whole thing is just a guideline--taking an exception to D1.5 in the state standard spec is a LEGAL modification to a LEGAL document. As far as I know, New York State (ironically, the state whose bridge manual D1.5 is based on) is the ONLY state that does not specify D1.5 as part of their standard specifications for bridge construction.
I've heard this notion expressed before, that D1.5 is just a guideline, and this is simply not true. It is an explicit part of just about every highway bridge contract in this country (except NYS of course).
That's not to say that, as for any other specification, it doesn't have its fuzzy parts, and parts that are open to interpretation, and areas in which enforcement is not as strong as in other areas. Again, that doesn't make D1.5 any more "just a guideline" than any other piece of a contract or specification.
Hg
HgTX
You are right of course. It is an AASHTO Standard. What I really mean to imply is that any State can, and will, take exception to any part of it that it doesn't like. I understand that many states take more than a "few" exceptions. If you look at the AASHTO Manual, each state is entitled to print Blue Pages that modify the basic document. So, I call the D1.5 and the AASHTO Manual a "Guideline".
I don't mean any offence by it. I happen to like the D1.5, (Especially when copmpared to the "LOOSEY-GOOSEY" D1.1). However, The NYSSCM is a better document. It isn't as broad based in the welding Code area as D 1.5, because NYSDOT limits the material you can use. I believe that there are fewer ambiguities in the NYSSCM, than in the D 1.5. In general, NYSSCM is more restrictive than D 1.5. I also have seen a few common fabrication details that are not covered by either the D 1.5 or the NYSSCM.
I understand from Mr. Paul Rimmer at NYSDOT, that the new NYSSCM will be more in line with the D 1.5. It may be like a D1.5 with a book of exceptions, like the state Blue Pages is to the AASHTO Manual.
On a bit of a tangent now but...
How is NYS Bridge Manual more limited in the material allowed? D1.5 allows only ASTM A 709.
Also, what states take lots and lots of exceptions to D1.5? I haven't seen "blue pages" anywhere but NYS, not that I've seen a majority of state specs, but I've seen a fair number of them.
I still maintain that "guideline" is an utterly wrong word to use with regard to D1.5 except for NYS. D1.5 may be a guideline for the new NYS manual. But for most if not all the other states, it's not just that it's an AASHTO standard, it is an AASHTO standard SPECIFIED by those states in their standard specs. Every single sentence not covered by a formal exception has the full force of the contract. Otherwise it's like saying that because there are amendments to the U.S. Constitution, that document is only a guideline. Being amendable does not make something any less legally binding; the fact that the formal amendments need to be made actually reinforces just how binding the document is.
Illustration by contrast: the AASHTO Construction Specs ARE a guideline in most cases. Last time I asked, I was told that about three states specify them outright (I don't know which). The rest use them as a source of boilerplate to write their own state specs. THAT is a guideline. Guidelines are optional. In something approaching 49 states, D1.5 is not.
I take this seriously because it is a dangerous attitude for anyone to take that D1.5 is just a guideline. If someone signs a contract (or subcontracts for a contractor that has signed a contract) that includes a statement like "all welding shall be done in accordance with D1.5", regardless of whether that statement is followed by "with the following exceptions", they better fill those requirements (as modified, if applicable), and not say they read on some website that D1.5 is just a guideline.
Hg
Joseph,
I think you've come closest to nailing it down. In my opinion, a level III does not have to be in line of site, however; They do have to either be contracted or otherwise available. I cannot think of an NDE program that doesn't require a level III at some point. I.E. A shop performing D1.5 NDE, the level II's have to have someone to go to when they need a determination for code interpretation. Most level II's can interpret specific procedures, and perform the work without a problem, but there is inevitably the odd argument between a supervisor or welder or someone else who thinks the Level II is not interpreting properly. At that point, the level III becomes necessary. I can understand why D1.5 requires Level III supervision on many levels, but I do not think it means standing there watching them, but rather supervision of a group of techs, or contracted as a level III to maintain a smaller organizations program and the occasional audit of the tech to meet QA requirements and interpretations when necessary.
One thing that is clear, a level III has to be in the loop at some point. What that point is, is open to interpretation.
SSBN727,
Just for the record.....I'm not all that familiar with the inter-workings of D1.5 ;-), I have dabbled in it but not proficient as I would like to be. Here at work we deal primarily with D1.1. This type work is very humbling. Anytime I feel like I'm starting to figure it all out, I learn something new and blow that theory.
From all that I've read and encountered in the past, the words "supervise" or "supervision" need to be ironed out when that wording is in question. As you can see many interpetations can be made. Like Joe Kane stated, it may or maynot be required for the Level III to be hovering over the Level II personnel...sorta depends on the situation and what the job specs have penned down in them for requirements.
Okay, now would be a good time to get an opinion from the folks @ ASNT about this because, it might help in clarifying the issue better. 
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