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9.2. Other General Information
When a fabricator receives direction that is conflicting with other direction on the project or with contract requirements or with safe practices the fabricator will draft a request for information describing the conflict in concise terms and ask for a resolution. The RFI should be submitted to the fabricator’s customer but if contract permits it can be copied to the Engineer of Record to save time. The reply technically comes from the fabricator’s customer but if the contract permits the fabricator can proceed on the basis of a reply by the Engineer of Record. If the engineer provides direction that the fabricators think is not safe, the fabricator should advise the engineer why the direction is unsafe and confirm the direction.
The International Building Code requires that structural steel fabricators have a quality control program. AISC Specification Chapter N provides a plan that IBC accepts. That plan includes provisions for personnel qualifications, documentation, and quality control and quality assurance procedures. Those procedures include inspection tasks and frequencies. When applicable, AISC Seismic Provisions Chapter J consists of additional requirements for quality control and quality assurance.
9.2.3. Why does AISC Specification Chapter N use the terms ‘observe’ and ‘perform’ when the other codes use ‘periodic’ and ‘continuous’?
The tasks delineated in AISC Specification Chapter N are all discernable in AWS D1.1/D1.1M. The terms observe and perform more accurately describe what is intended. Periodic implies the inspector is there some of the time, and continuous implies the inspector is there all of the time. When the inspector is on the site is not the point. The point is what the inspector sees and how the inspector chooses to witness and collect evidence that the work is being performed in compliance with specification requirements. The concept of observe includes increased frequency at the beginning of projects and for critical elements. The concept of observe is used for tasks and procedural elements that tend to remain in place, personnel are qualified, consumables are complaint, procedures are in place, and documentation is available. It may also be used where 100% inspection is too expensive. Perform means 100% inspection. It does not mean the inspector has to be there during all work. It is often used on tasks that can be accomplished after the work is done. But it has to be done on every joint. The observe and perform concepts utilized in Chapter N will focus inspection where it does the most good and reduce waste.
9.2.4. Is Ultrasonic Testing (UT) reliable? Is UT of value? Is Phased Array Ultrasonic Testing (PAUT) a vast improvement over traditional UT?
In order: no, yes, and maybe.
UT takes skill. UT has been shown multiple times to not find all flaws and to find flaws that are not rejectable. It is an imprecise tool. Welders will take more care if they know the weld will be tested. UT should be used as required in AISC Specification Chapter N. While PAUT does not solve all the problems associated with traditional UT it can provide documented records and it can improve precision. It does take the same skills as traditional UT plus knowledge of PAUT. PAUT is relatively new in the structural steel industry and therefore may entail extra costs. It will eventually become more competitive. In the interim, it is worthwhile in select applications.