Re: [PipingDesign] Re: All the talks about CII?

From: <Jun>
Date: Thu Apr 12 2007 - 02:20:00 EDT

  1. When the piping system is already in-service - there is only one view. That it is fit for continued service. Doesnt matter which group you belong - it boils down to responsible care.
  2. In the place where i work the desgin basis has always been designed (not operating as previously stated) condition - be it an upset, expansion or Code.
  3. First thing first - how do one classify wether the piping system is critical or not? What is the basis? Do piping stress engineers analyzed the critical or non-crtical piping differently? Do CII even recognized a critical or non-critical piping and once the distinction has made approaches it differently?
  4. OK. Let us say that the piping system that has been designed using CII and was built/installed following the B31 rules. After several years of operation - deterioration has been observed such as local metal loss or lamination or weld misalignment after inspection? Im still at loss on how can the CII be utilized to evaluate wether the piping system or its componet is still fit for continued service or not.
    • Original Message ---- From: Farhad <> To: Sent: Wednesday, April 11, 2007 8:38:02 AM Subject: [PipingDesign] Re: All the talks about CII?

There are different views between maintenance/ operator engineers and design engineers. Piping systems are designed for their operating conditions during design phase but there are also several things that must be considered for plant life cycle as well, i.e. fatigue, earthquake, liquid hammer, natural frequency checking, relief valve firing, etc. Critical pipings also must be fully checked against their different operating conditions during plant life cycle, i.e. pipes connected to fixed and rotating equipment. Then a few years after plant startup, you'll see new piping problems reported by field engineers. At this time you need an expert stress engineer with a good fab/maintenance/ design/CII knowledge to model and solve problems.
Piping stress programs are tools for evaluating designed piping systems, so it's up to engineers how to use them. CII or other programs can handle all types of required analysis and evaluations. I'm a CII instructor and I see many stress engineers who are working with software for several years without knowing all program's capabilities.

I hope this clears that when and why we use software.

Farhad Salehi


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[Non-text portions of this message have been removed] Received on Thu Apr 12 02:20:00 2007

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