The Pipe Flexibility Study (Pipe stress analysis) is an important process in pipe design. After the route is drawn, following the design guidelines, it is verified through a stress analysis that the pipe works without problems during its life, taking into account the standard that applies according to the codes.
These studies take into account physical phenomena such as thermal expansion, the weight of the pipe, the weight of accessories and supports; When these pipes come into operation, they cause stress that damages some supports, nozzles, restrictions and generates torsion in some cases. All these events are verified in an analysis and compared with the ASME code taking into account the material of the tubes and the process conditions of the system; It is the basis for making a flexible solution proposal.
In conclusion, a Stress analysis is a static study that calculates the stresses suffered by pipes and accessories; ethese stresses are internal and are compared against the maximum allowable stresses of each material at the process conditions. Additionally, it calculates the forces and moments that the pipe generates at the restricting points, for example, supports and nozzles. With this information, system designers design the structures that will support the piping system and verify if the nozzles are sufficiently resistant to the forces and moments that are reaching them.
Advantages of a flexibility study for a pipeline line:
- Avoid cost overruns due to poor selection.
- Limits the loads on nozzles of connected equipment within allowable values.
- Avoids buckling of pipes.
- Optimizes the pipe routes and the number of flexible elements.
- For lines with the same characteristics, only one analysis should be done.
The software used by us for pipe analysis is CAESAR II, which is based on the ASME code and is classified according to the fluid being handled. The design standards are:
- B 31.1 Power piping and steam systems.
- B 31.3 Process piping.
- B 31.4 Transport of liquid hydrocarbons.
- B 31.8 Gas transmission and distribution pipes.
- ASME BPVC (Section II, V, VIII). General requirements.
Design and calculation of expansion joints:
- EJMA (Expansion Joints Manufacturers Association)
Steam turbines:
NEMA SM 23. (National Electrical Manufacturers Association)
Pumps, compressors and other equipment:
- API standards.
Standards for the calculation and design of supports are also involved:
- MSS SP 58.
- MSS SP 69.
- MSS SP 89.
Flexilatina de Colombia has extensive experience in different fields of the industry nationally and in part of Latin America in which it has carried out different studies for projects in sugar mills, thermal plants, textile plants, power generation plants through steam turbines and in some cases gas turbines, among others.
Some of the industries where we have participated with our studies are the sugar, paper, power generation, steel, chemical, petrochemical and Oil & Gas; To companies such as Prime Termoflores, Brinsa, Termoguajira, Compañía Eléctrica de Sochagota, Bioenergy, Ingenio del Cauca, Ingenio San Carlos, Ingenio Providencia, Manuelita, Propal, Smurfit Kappa and Termosierra.
We make the difference due to our extensive experience of more than 30 years in selecting and manufacturing flexible elements to solve the problems detected in a Stress analysis.
Image 1. General isometric.
Image 2. Max. voltage along the path of the pipe (color code).