The initial cost is not always the deciding factor. The first consideration is the operating condition of pressure, temperature and corrosion that mandate material selection. How flexible is the system to expand or modify? The ability to use in-house staff for modification can be an important cost saver.
Cost of operational maintenance must be factored into the assessment as well as initial installation. Local, state and federal regulations and codes affect fabrication methods and approved materials. Relative weight of components materially affects the hanging costs of installation. Flow characteristics can influence cost of pumps and erosion of materials.