What design considerations are critical when selecting pipe material for a system handling highly corrosive fluids?

When selecting pipe material for a system handling highly corrosive fluids, several design considerations are critical. First and foremost is the chemical compatibility of the pipe material with the specific fluid being transported. The material must be resistant to the type of corrosion that the fluid can cause, whether it be uniform corrosion, pitting corrosion, crevice corrosion, or stress corrosion cracking. This resistance needs to be evaluated over the full range of operating temperatures and pressures. Secondly, the mechanical properties of the pipe material must be suitable for the application. This includes its tensile strength, yield strength, and ductility. The pipe must be able to withstand the internal pressure of the fluid, as well as any external loads or stresses. The material's resistance to erosion and abrasion should also be considered, especially if the fluid contains solid particles. Thirdly, the method of joining the pipes is crucial. The welds or joints must also be corrosion-resistant and must maintain their integrity over time. The welding procedure and the welding material need to be carefully selected to ensure compatibility with the pipe material and the fluid. Fourthly, the cost of the pipe material and installation should be considered. While it is important to select a material that is corrosion-resistant, it is also important to choose a material that is cost-effective. In some cases, it may be possible to use a less expensive material with a corrosion-resistant lining or coating. Lastly, code compliance is essential. The pipe material must meet all applicable codes and standards for the intended application. These codes specify minimum requirements for material properties, design, fabrication, and testing.