Pipe Stress Analysis Introduction

As far as readers concern , I begin my piping career from starting a pipe stress engineer and no doubt the first topic will be touched is on pipe stress analysis. Without going futher , i will brings readers to tour around the reason of we need a pipe stress analysis in piping industrial. Pipe stress analysis is to assure the quality and feasiblity of piping system , a pipe stress analysis is compulsory for every project and generally will be performed by mechanical engineer with at least bachelor degree in mechanical engineering and at least 5 years working experience in piping industrial.

As i mentioned before , stress analysis duty as a auditor to verify the piping system flexibility by checking against with design code . Beside that , also represent as a checker to check the maximum stresses against allowable values to prevent fatigue failure due to cycles of temperature expansion. Also. verify and limit the reaction forces & moments at terminal point and ensure the vertical displacement are within the code allowable. Furthermore , pipe stress engineer also holding the authority to determine the pipe wall thickness , selection of expansion bellow ,selection of equipments , selection pump and so on. Before selection of this heavy equipment , pipe stress engineer shall carry out an overall research and study before the conclusion is confirmed , this process involved a lot calculation and varies angle of consideration. In conclusion, i can say that pipe stress job look easy but high responsible , as a pipe stress engineer must be aware of the calculation , a single careless mistake may loss million dollars of money.

From where can we learn pipe stress analysis ? i can suggest the fresh graduate or engineer without piping knowledge to look for famous engineering consultancy such as Technip , Aker Kvaerner , Worley Parkson ,Foster Wheeler , CB&I and otherwise look for FRP pipe vendors because according code ISO 14692 , stress analysis for FRP shall performed by pipe vendor. The list of company provide sufficient information for a fresh graduate to gain the basic concept of piping and pipe stress philopsophy . Mastering the design code will be the 2nd options to improve the pipe stress knowledge , please find the ASME code as below may help much on improving for piping knowledge .From my personal recommendation , mastering code ASME B31.3 is more than enough for oil and gas industrial.

1. ASME B31.1 Power Piping
2.ASME B31.3 Process Piping ( Widely used in chemical and refinery plant )
3.ASME B31.4 Liquid Transportation Piping
4.ASME B31.8 Gas Transportation Piping
5.ASME Section III, Nuclear Components Design

The advance of the technology has accelerate the evolution of composite piping such Fibreglass Reinforced Pipe (FRP) as a result numbers of steel line today has been widely replaced by FRP pipe due to their reliablity , corrosion-free , simple installation , light in weight and etc. The lines such as Firewater , drain line , sewage water line , service water line has been replaced by FRP piping instead of metallic . The major between steel pipe and FRP pipe is steel pipe is isotropic materials (Having identical value of property in all crystallographic direction) while FRP pipe is anisotropic(Property vary systematically depending on the direction either hoop or axial) materials . Inasmuch as it happen slightly different in the calculation thus when dealing with FRP piping is recommended to refer the design code as follow :

1. BS 7159
2.UKOOA
3.ISO 14692

Summary of the chapter

Objective of pipe stress analysis to :

1.Ascertain the pipe support location.
2.Check the reaction force and moments at each support location or nozzle or terminals point.
3.Check the vertical displacment against the code allowable.
4.Check the flexibility of the piping between nozzle to the equipments.
5.Ensure the piping has enough flexibility to expand.
6. Compare the stresses result against the allowable code stress.
7. Verify the usage of appropriate equipments.
8. Identify the high forces, bending moments , overstress location and propose solution in order to maintain
system flexibility.