No. There is no official agency preference for one material over another. Whatever material a firm selects for its WFI system must be suitable for its intended use. This holds true for virtually all production equipment.
When evaluating the suitability of a WFI system’s piping, consider the surface texture or finish of the piping’s interior wall (e.g., smoothness, waviness), its ability to resist high temperatures and pressures, and its ability to withstand sterilizing and sanitizing agents and procedures.
Equipment surfaces that are in contact with components, in-process materials, or drug products must not be reactive, additive, or absorptive so as to alter the drug product’s safety, identity, strength, quality, or purity beyond its official or established requirements.