Updated: Nov 6
Pipe Stress and Flexibility Analysis
The analysis of piping stress and flexibility lies at the core of our business. We find that unexpected mechanical problems requiring frequent maintenance and/or shut-downs are often caused by an insufficient level of quality in the design of the connected piping system and related structures. Efficiency and therefore profitability suffer, leading ultimately to permanent damage and high costs for repair and maintenance. In many cases, original designs do not consider temperature differentials during non-equilibrium conditions such as start-up, shut-down, rapid restart or other upset conditions. In situations like these, system elements such as equipment nozzles, foundations, piping flanges, spring supports, rigid supports and other system elements can be overloaded above the levels originally anticipated by the designer. This can lead to serious problems. Meena Development LTD. has years of experience in analyzing the flexibility of and stresses associated with piping and related structures. Our expertise combined with the following commercial programs have consistently produced reliable answers to complicated problems for numerous satisfied customers.
Meena Rezkallah, P.Eng., our piping stress engineer provides standard CSA / ASME Code calculations for common pressure vessel assessment. An adjunct program determines stresses at a vessel shell / attachment intersection: The calculations report the WRC 107 and/or WRC 297 analysis. The results indicate longitudinal and circumferential membrane and direct shear stress due to externally loaded vessel shell connections, and longitudinal and circumferential stresses due to vessel internal pressure. These stresses are summed as the largest difference of principal stresses for the combined stress intensity. The combined stress intensity is compared to the allowable stress. Reinforcing pad thickness and diameter are automatically designed and evaluated. CAESAR II© calculates static and dynamic response properties of complex piping systems and structures using finite element techniques using beam theory elements, and solves one-dimensional transient heat transfer problems for piping. The program can be used to analyze a wide variety of problems. The static capability includes the computation of piping and structural deformations and member loads and stress caused by an arbitrary set of thermal loads, applied loads, and displacements. The dynamic capabilities include mode shapes and natural frequencies, response spectra, phased harmonic load analysis, time history dynamic analysis and force spectra analysis. For modal analysis, CAESAR II can automatically insert mass points along elements. CAESAR II provides built- in fluid transient synthesizers for calculation of water hammer, steam hammer, and relief valve forces, which are integrated with time history dynamic analysis.
Piping Supports Design
Meena Development LTD. can also provide structural analysis and design for piping systems restraints/supports and foundations for associated machinery, as well as that required for plant design or retrofitting. Working a piping system and its related structural work together is the key. As the main function of a plant or facility is to produce, the actual process receives prime consideration and therefore the supporting structure must assist in the production process, not restrict or hamper it.
Meena Development LTD. also provides structural analysis and design for piping systems and associated machinery, as well as that required for plant design or retrofitting. Working a piping system and its related structural work together is the key. As the main function of a plant or facility is to produce, the actual process receives prime consideration and therefore the supporting structure must assist in the production process, not restrict or hamper it. Our long term experience in system analysis and design makes us well aware of the requirements which must be met by a supporting structure, foundations and other key elements.
Finite Element Analysis
For detailed analysis of piping components such as tube sheets, branch connections, nozzle connections, flanges, tees, lifting lugs or any other object, structural or otherwise, which may be under undesirably heavy loads and/or stresses, we use finite element techniques and software. We regularly create 2D and 3D models to predict mechanical stresses due to pressure, temperature, and other applied loadings, as well as vibrational frequencies and heat transfer calculations.
A major part of our business activity is the review of design failures that present as operating failures in the field. Although many design issues can lead to a piping system failure, there are three main causes:
Poor original design: Design conditions, whether unknown, unexpected or overlooked, were not properly considered — or they were considered but were not adequately planned for. Often, piping systems are not correctly supported and restrained to properly distribute and control thermal displacements and to minimize sags. Piping stresses not predicted by calculations thus occur because the system does not cycle between its original, installed location and an operating, or displaced, position. Instead, as it is cycled, these stresses tend to migrate to new locations depending upon friction loads and temperature gradients. Also, unexpected flow-induced dynamics can occur and, if long unsupported spans exist, they can easily become excited and cause cumulative fatigue damage.
New design conditions: The original design conditions of the system have been changed and the new temperatures, pressures, or flowrates were only considered as process changes and were not reviewed for mechanical considerations.
The piping system or equipment needs more consideration than standard piping codes provide: Codes such as the ASME B31.1, ASME B31.3, ASME Section VIII, Division 1 code, and numerous others have considerations for many situations, but there are times when additional calculations, beyond the official requirements, are needed. Good examples include tube sheets with temperature differentials greater than approximately 200 F, nozzle-to-shell connections that do not fall within WRC 107 curves, and flat heads with non-circular openings.
Our years of experience allow us to quickly suggest which item above is most likely responsible for the failure, then we can use the most appropriate techniques and programs to identify the specific problem and recommend an efficient solution.
Because Meena Development LTD. offers an array of multidisciplinary services (Pipe Stress Analysis and Structural Engineering), we can provide solutions across a multitude of industries. The listing below indicates a few of Meena Development’s most commonly served industries.
Located in Calgary Alberta, We offer our Piping Engineering Services, Skid Design Services, Pipeline Engineering Services and Structural Engineering Services across Canada. To get our Piping Stress Analysis Services, please contact our Engineering company.
Our professional piping stress engineers have a bachelor's and Masters degree in mechanical / structural engineering and province license (P.Eng.) in Alberta, Saskatchewan, British Columbia and Ontario. We review, validate, certify and stamp piping and structural packages. Also check Industries We Serve.