DNVGL-ST-F101: Code Check Article

all about pipelines
Dated: 22 Jan 2018

Dear Users,

A warm greeting from the Team of all about pipelines involved in development of DNVGL-ST-F101: Code Compliance Web-application. After a long haul of three months, our team is happy to bring forth this web-app and hope that your design experience with this web-app is enjoyable. Our pipeline & software group have put tremendous efforts to provide the minutest flexibility which a designer needs in performing and optimizing the wall thickness analysis for submarine pipelines as per DNVGL-ST-F101, 2017. The output of the web-app has been meticulously checked and reviewed for all types of different scenarios which may be encountered during design process and has been found in order. However, we believe that there may still be a possibility of improvement and further optimization by our extra-ordinary users. Therefore, we request you to enlighten us by your kind feedback by pressing the blue button located in the bottom right corner of the web-app. (Constructive feedback may earn you a free membership of upto 3 months)

Team - all about pipelines
NT Technologies
The web-app has been designed to be largely intuitive. Brief description of the features which are built-in this web-app are as below:

  1. The following code checks are included:
    • Pressure containment (Bursting)
    • Local buckling
      • External over pressure only (System Collapse)
      • Propagation Buckling (may be superseded by DNV-1981 formula in case D/T > 45 as per user’s choice)
    • Local buckling - combined loading criteria
      • Load Controlled condition (LC condition) (moment, axial force, external/ internal overpressure and lateral point load)
      • Displacement Controlled condition (DC condition) (axial strain, external/ internal overpressure and lateral point load). It also includes the considerations for material having Lϋder plateau.

  1. Safety class and assumptions regarding corrosion, de-rated material, minimum sustained pressure and point load can be selected individually for the different limit states/ conditions by selecting the respective checkboxes on the input page as shown in the image below.
  1. The checkbox for "minimum sustained pressure" for load controlled & displacement controlled limit states is disabled if the pipeline condition is selected as “empty”. For simulating the normal installation of pipeline, the user shall select pipeline condition as empty. However, if the user selects the pipeline condition as “water-filled installation” then it is understood that the user wants to take advantage of “minimum sustained pressure” option during installation, therefore the checkbox is checked & then disabled and the user is prompted to recheck the loads for minimum sustained pressure conditions.
  1. The web-application calculates:
    • the minimum required nominal wall thickness for the given conditions
    • utilization based on a wall thickness given by the user
  2. The results are shown in the output page separately for burst (operation & system test), collapse & propagation and load interaction calculations.
  1. Being hosted on web, inherently, makes this application system-independent which can be accessed anywhere & anytime. The web-app is mobile & tablet friendly. Server-side coding has been done in C# using asp.net platform and client-side coding has been done in HTML 5 supplemented with javascript using bootstrap v3.2.
  1. Report generation: When the user is also a member, then well-formatted report in ‘Microsoft word’ format can be downloaded from the web-application:
    • One sheet for burst check, system test condition and operation,
    • One sheet for system collapse and propagating buckling,
    • Two sheets for load controlled load interaction, load cases ‘a’ & ‘b’, and
    • Two sheets for displacement controlled load interaction, load cases ‘a’ & ‘b’
  2. These report sheets are meant for paper print-out and inclusion in reports. They contain all relevant input, some intermediate results (to ease external verification) and the results from the code check. The users who are accessing the report generation feature for the first time can download the report twice for free. Members, if desire, can get an upgrade of downloading customized report with their company logo in the report.
  1. Input page can be reached by any user without any requirement to log in the app. The user can access the output page free of cost by logging in (or registering in case of new user and then log in). This has been done to meet NT Technologies goal of making available the most sophisticated designing platforms to pipeline designers free of cost.
  1. The program is made to fit engineering purposes, with output page including users input and calculation result showing minimum wall thickness & utility promptly and intermediate results for each load case in separate collapsed forms. The user can navigate back from output page to input page with same input parameters by clicking the link to "input page" which is next to the home button in the top left corner. In case, user wants to open the input page in new tab then same can be achieved by clicking the button titled "Input Parameters" as shown.
  1. Record keeping: All the user data are safely stored in our databases. Once the data is stored, an email is sent to the user on his/ her registered email address which includes the link to the output page and a table containing the input parameters. In case, the user does not want the email for record then same can be stopped by unchecking the checkbox just above the calculate button at the bottom of the input page, as shown in the image below.
  1. Explanations to the terms in input page are given as hover comments, which can be seen by holding mouse on top of them for a second as shown in the figure below. The app also has an error check mechanism to identify any gross error in the inputs from the user before processing.