Author Archives: pandian77

WRC 107 & 297 wizard in CAESAR II

Whenever Pressure Vessel or Heat exchanger (Static Equipments) nozzle loads exceeds the allowable values provided by Vendors (Equipment manufacturer) or standard project specific tables (guidelines), the piping stress professional is permitted to use WRC 107/297 (or any other FEA) to check the stresses at the Nozzle-Shell junction point and check the stresses with allowable values provided by Codes.

WRC-107, entitled “Local Stresses in Spherical and Cylindrical Shells due to External Loadings”, was released in 1965 and updated in 1979. WRC-297 was released in 1984 and goes under the title of “Local Stresses in Cylindrical Shells due to External Loadings – Supplement to WRC Bulletin No. 107”

Assumptions & limitations for using WRC 107:

To determine whether WRC 107 bulletin can be used for local stress checking the following geometry guidelines must be met:

  1. Nozzle Connection is assumed to be a rectangular loading surface (no nozzle, no hole) for circular and longitudinal moment loads. In short, not for nozzle stress calculations.
  2. WRC 107 has no provision for pressure loads. The adding of pressure to external loads has historically been problematic for WRC 107 calculations.
  3. Shell reinforcements are not considered.
  4. WRC 107 does not provide flexibilities of the intersections
  5. d/D<0.33
  6. Dm/T=(D-T)/T>50 (Here, T=Vessel Thickness, Dm=mean diameter of vessel)
  7. Not intended for small D/T ratios.

Assumptions & limitations for using WRC 107:

To determine whether WRC 107 bulletin can be used for local stress checking the following geometry guidelines must be met:

  1. Includes effect of nozzle, nozzle opening and nozzle thickness.
  2. Does not include pressure effects. (See WRC 468)
  3. Includes stiffness calculations in Fig 59&60 that can easily be used to produce numbers that are off by several orders of magnitude (high and low) since extrapolation on log-log plot is required for geometric parameters.
  4. Shell reinforcements are not considered.
  5. d/D<=0.5
  6. d/t>=20   and d/t<=100   (Here t=nozzle thickness)
  7. D/T>=20   and D/T<=2500
  8. d/T>=5
  9. Nozzle must be isolated (it may not be close to a discontinuity) – not within 2√(DT) on vessel and not within 2√(dt) on nozzle

Parameters required for performing WRC checking:

The following documents must be ready with you before you start to perform WRC 107/297 checking:

  1. Equipment Details/ General Arrangement Drawing
  2. Nozzle details
  3. Line list

Procedure for WRC analysis:

  1. Static analysis of the piping system must be performed and nozzle loads are calculated for local stress calculations.
  2. Look for WRC icon under your analysis tab. Click here and enter a job name in the space provided.

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  1. Select which one you would like to perform.

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  1. Give the required input for Nozzle.

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  1. Give the required input for Vessel

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  1. Input vessel and Nozzle direction cosines, Internal design pressure and load and moments values from Caesar static analysis output (Sustained, Expansion and occasional as applicable). Define path of C2 file.

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  1. It is recommended to not to change any parameter under “Options” tab. Now click on analysis to read the results. Check the result for WRC analysis wether it is failed or passed.

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Note:- For WRC 297, If below highlighted field sets to True. The program will compute local stresses in accordance with British Standard 5500 Annex G instead of Welding Research Council Bulletin 297.

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Please Join ImageGrafix’s Wednesday Webinars – July 2015

ImageGrafix Wednesday Webinar

July 2015

Incompressible Fluid Flow Analysis Using AFT FathomAFT FEA Analysis Tool for PVElite Users

PVElite

Convert Laser Scan Data to 3D Intelligent CADWorx ModelCADWorx
Date: July 08, 2015Time: 09.00 AM(Qatar, Kuwait, Bahrain) 10.00 AM (UAE, Oman) 11.30 AM (India) Duration: 30 Min Cost: Free Webinar

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Date: July 15, 2015Time: 09.00 AM(Qatar, Kuwait, Bahrain) 10.00 AM (UAE, Oman) 11.30 AM (India) Duration: 30 Min Cost: Free Webinar

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Date: July 22, 2015Time: 09.00 AM(Qatar, Kuwait, Bahrain) 10.00 AM (UAE, Oman) 11.30 AM (India) Duration: 30 Min Cost: Free Webinar

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Description:We’ll provide an overview of how to model your Incompressible system using AFT Fathom software. This Webinar covers

• Basics of building and defining your model • Pump sizing • Pressure Drop Calculation • Flow Distribution • Velocity Checking • Understanding system behavior etc.

Description:Nozzle/PRO Software enables users to quickly and easily perform Finite Element Analysis (FEA) of individual pressure vessel and piping components.

Nozzle/PRO enables FEA results to be seamlessly incorporated within PVElite to improve the overall analysis of vessels so they are neither over- nor under-designed.

Description: CADWorx fieldPipe with CADWorx Plant Professional helps to convert the Laser Scan Point Cloud Data to 3D Intelligent Modeling in the AutoCAD Environment. In this Webinar, we will covers • How to bring the Point Cloud Data inside CADWorx fieldPipe • Convert the same to Intelligent 3D Model • Extract the Isometrics Drawing with Bill of Materials
Speaker Bio:Arjun Kapoor, a Chemical Engineer by profession is working as a Product Manager for Process & Simulation Solutions at ImageGrafix Engineering Services Pvt. Ltd. His responsibilities include product presentations, training and technical support for AFT, Flaretot and Instrucalc Software Speaker Bio:K M Pandian, a Mechanical Engineer by profession is working as a Technical Manager for Plant Design Solutions at ImageGrafix Software FZCO. Having 19 Years of experience in project, Product demonstrations, training and end user support for CAESAR II, PVElite, TANK & PRG Software. Speaker Bio:Saravanan Padmanabha Pillai , a mechanical engineer by profession is working as a Technical Consultant with ImageGrafix Software FZCO, Dubai. Having 10 years’ of hands on experience on BIM/plant Projects implementation, Technical Support, content creation, & Training on CAD Products
              Arjun            KMP Photo           Saravanan CW
Copyright © 2015 ImageGrafix Software FZCO. All rights reserved.

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How to restore corrupted CAESAR II file?

Those who are extensively using Caesar II software must have noted that sometimes few Caesar II files got corrupted due to some reason. And modeling the same file from isometric again is time consuming. At the same time the man hour used is lost without any fruitful result. The same happened to me yesterday. Unconsciously I deleted the required file and i was a bit worried as i had to redo the modeling again.

In such situation you can easily restore the complete Caesar model without much pain. This write up will try to explain the method of restoring the Caesar II file which is corrupted or deleted by mistake. However this will only work if you have performed the run function at least once. The load cases what you made will be lost and you have to make new load cases for the analysis. And i feel that’s better as making load cases does not take much time.

Whenever you prepare any Caesar file and then run the file for analysis a backup file of the stress system is automatically generated in the PC. Later that back up file can be used to restore the required Caesar file again.The steps are as follows:

  1. Click the open button on Caesar II and you will get the following screen.

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  1. Now click on the System button on the right side as shown in the above picture.
  2. After that page up button on top and you will get the following screen.
  3. Now Click on the back up file as shown in the above figure and choose your file. You must remember the file name to restore the same. Choose the latest file as per date and time to get the most updated information.

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  1. The Caesar file will be restored for you. Now save that file to the location where you want that to be and make the load cases as per your requirement for analysis. Hope this helps you to resolve few of your problems and save man hour.

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Propagating Caesar II properties

Here I would like to discuss about the essential properties automatically propagating over to subsequent elements in Caesar II.

What happens when you define properties like pipe diameter, schedule/Wall Thk, temperature, pressure etc. to an element? Did you notice that you need not to enter these properties again for following element? This is a helpful feature in Caeasar II that, when you define properties on an element, the software carries forward these properties to all subsequent model elements thereafter, until you explicitly change the property value.

But what if you want to change these properties? I believe you are not going to change this very often. Below figure is going to explain you which property is going to be retained when you go over a new element and which you might want to change based on your requirement.

In below spreadsheet image from Caesar II piping input properties shown below in orange are carrying forwarded to next element:

Pic 1

In the same image properties depicting in yellow are going to get changed based on pipe routing.

Check the Element List below, here it shows explicit data values in red and carry-forward properties in gray. This notation makes verification and editing quick and easy.

Pic 2

CAESAR II 2014 (Version 7.0) introduced a new feature where you can edit certain properties namely pressure temperature, schedule etc. over a block data, using the Legend dialog boxes. These dialog boxes helps you to review input properties graphically and added editing capabilities to the Legend dialog box values. You just need to double-click a value, Caesar II interface displays an Edit box in which you can specify a new value. This updates the edited value immediately in the piping input and on the model.

Check out the image below which depicts the new value edition in Legend dialog box:

Pic 3

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How AFT Impulse Can Help Engineers to Comply With ASME Codes

Engineers are often responsible to design systems to comply with codes and standards. In recent years codes that apply to waterhammer and surge pressures have become more prominent. Increasingly AFT Impulse is being used to help engineers comply with such codes. Once AFT Impulse has calculated the maximum pressure due to a transient event, what shall the designer do with this value? The answer to this question depends on the code that is being used as the piping design basis. In this article we’ll be discussing how two important piping design codes – B31.4 and B31.3 – deal with surge pressure (transient pressure) and how the results from AFT Impulse shall be used in order to comply with their requirements. Codes

  1. ASME Code for pressure piping B31.4. Pressure Transportation Systems for Liquid Hydrocarbons and Other Liquids.

401.2 Pressure 401.2.2 Internal Design Pressure. The piping component at any point in the piping system shall be designed for an internal design pressure which shall not be less than the maximum steady state operating pressure at that point, or less than the static head pressure at that point with the line in a static condition. The maximum steady state operating pressure shall be the sum of the static head pressure, pressure required to overcome friction losses, and any required back pressure. Credit may be given for hydrostatic external pressure, in the appropriate manner, in modifying the internal design pressure for use in calculations involving the pressure design of piping components (see para.404.1.3). Pressure rise above maximum steady state operating pressure due to surges and other variations from normal operations is allowed in accordance with para. 402.2.4.

402.2.4 Ratings – Allowance for Variations From Normal Operations. Surge pressures in a liquid pipeline are produced by a change in the velocity of the moving stream that results from shutting down of a pump station or pumping unit, closing of a valve, or blockage of the moving stream. Surge pressure attenuates (decreases in intensity) as it moves away from its point of origin. Surge calculations shall be made, and adequate controls and protective equipment shall be provided, so that the level of pressure rise due to surges and other variations from normal operations shall not exceed the internal design pressure at any point in the piping system and equipment by more than 10%. From B31.4 extracted paragraphs the following conclusions can be drawn:

  1. B31.4 refers directly to the maximum value of the overpressure, establishing a limit of 10% above the Steady State operating pressure.
  2. As the reference pressure B31.4 uses the static state pressure, in other words the designer shall use the Max. Static pressure from AFT Impulse instead of the Max. Stagnation pressure.
  3. Operating pressure shall be the reference for design instead of the design pressure calculated for the pipe.
  4. ASME Code for pressure piping B31.3. Process Piping

301.2.2 Required Pressure Containment or Relief

  1. (a) Provision shall be made to safely contain or relieve

(see para. 322.6.3) any pressure to which the piping may be subjected. Piping not protected by a pressure relieving device, or that can be isolated from a pressure relieving device, shall be designed for at least the highest pressure that can be developed. (b) Sources of pressure to be considered include ambient influences, pressure oscillations and surges, improper operation, decomposition of unstable fluids, static head, and failure of control devices. (c) The allowances of para. 302.2.4(f) are permitted, provided that the other requirements of para. 302.2.4 are also met.

302.2.4 Allowances for Pressure and Temperature Variations. Occasional variations of pressure and/or temperature may occur in a piping system. Such variations shall be considered in selecting design pressure (para. 301.2) and design temperature (para. 301.3). The most severe coincident pressure and temperature shall determine the design conditions unless all of the following Criteria are met: (a) The piping system shall have no pressure containing components of cast iron or other nonductile metal. (b) Nominal pressure stresses shall not exceed the yield strength at temperature (see para. 302.3 of this Code and Sy data in BPV Code, Section II, Part D, Table Y-1). (c) Combined longitudinal stresses shall not exceed the limits established in para. 302.3.6. (d) The total number of pressure-temperature variations above the design conditions shall not exceed 1000 during the life of the piping system. (e) In no case shall the increased pressure exceed the test pressure used under para. 345 for the piping system. (f) Occasional variations above design conditions shall remain within one of the following limits for pressure design. (1) Subject to the owner’s approval, it is permissible to exceed the pressure rating or the allowable stress for pressure design at the temperature of the increased condition by not more than (a) 33% for no more than 10 hr at any one time and no more than 100 hr/yr, or (b) 20% for no more than 50 hr at any one time and no more than 500 hr/yr.   From B31.3 extracted paragraphs the following conclusions can be drawn:

  1. Surge pressure is included in the group of loads called occasional.
  2. The piping design pressure shall take into account the maximum pressure that may occur in the system including surge pressure due to a transient event.
  3. The maximum surge pressure shall not exceed in any case the test pressure calculated for the pipe.
  4. The maximum stress produce the loads created by the surge pressure shall not exceed: 1.33 S(Sh=allowable stress for the operating temperature).

In order to meet the 3rd requirement the AFT Impulse user shall calculate the forces originated on  the bends of the system  and feed this data to a pipe stress program (see Trey- Jim Wilcox article: Evaluating Dynamic Loads in Piping Systems Caused by Waterhammerhttp://www.aft.com/training/white-papers) Conclusion The allowable pressure due to a transient event (surge allowable) varies from code to code. B31.4 refers directly to the maximum pressure value establishing as a limit 10% above the operating pressure. B31.3 not only establishes a surge pressure allowable (Test pressure) but also deals with the mechanical effect in the pipe, limiting the limiting piping  stresses to a maximum of 33% above Sh (Sh=allowable stress for the operating temperature).

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ImageGrafix Wednesday Webinar “What’s New in PVElite 2015”

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Date: May 27, 2015

Time: 09.30 AM UAE Time and 11.00 AM India Time

Time Duration: 30 min

Cost: free webinar

Register

Webinar Description:

Discover the latest advances in PV Elite 2015. Design equipment for the most extreme uses quickly, accurately and profitably by taking advantage of:

  • The new 3D PDF modeler
  • CodeCalc improvements
  • Output processor enhancements
  • Additional configuration options
  • Improved analysis capabilities
  • And much more!

Speaker Bio:

Deepak

Deepak Sethia, a mechanical engineer by profession, is working as an Application Engineer for Plant Design Solutions with ImageGrafix Software FZCO, Dubai. He is a seasoned piping and static equipment design engineer with 7 years of experience in providing technical support and end user training on Intergraph CAESAR II, PV Elite and Tank software

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by | May 14, 2015 · 11:06 am

ImageGrafix in SteelFAB 2015 – Meet us at Stall No 4556 Expo Centre Sharjah from January 26 – 29 2015

SteelFab 2015, the 11th edition of the region’s premier exhibition for the metal working, metal manufacturing and steel fabrication industry is set to be held at Expo Centre Sharjah from January 26th to 29th 2015. Over the last 10 editions SteelFab has grown in size and content to become a complete show that caters to the A-Z requirements of the Middle East Steel industry.

ImageGrafix Software FZCO, a 19+ year’s old company based in Dubai, United Arab Emirates (UAE) is one of the leading value-added-distributors, developers and engineering service providers in the Middle East and Egypt. We distribute and support industry standard engineering applications developed by well-known software developers including INTERGRAPH, AUTODESK, SUNRISE SYSTEMS, PAULIN RESEARCH GROUP, DIMENSIONAL SOLUTIONS, and RASTEREX etc.

ImageGrafix Software FZCO is participating in SteelFab 2015 to showcase our CAD/CAM/CAE solutions.
We invite you to visit our booth # 4556 to see live presentation of 3D Digital Prototyping, Simulation and Manufacturing solutions and you get a chance to interact with technical experts.

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