What material should every removable plug, cap, nut, or bolt from a ferrous fitting be made of?

The correct choice is that every removable plug, cap, nut, or bolt from a ferrous fitting should be made of non-ferrous material. This is crucial because non-ferrous materials, which do not contain iron, are less likely to corrode when in contact with ferrous fittings. Corrosion can lead to leaks, failure of joints, and other significant plumbing issues, thereby compromising the integrity of the plumbing system.

Non-ferrous materials, such as brass, bronze, or certain alloys, provide resistance to corrosion, making them suitable for use in plumbing applications that involve ferrous metals. This compatibility helps ensure longevity and reliability in plumbing installations, promoting overall durability.

In contrast, materials like plastic may not withstand the physical stresses and pressures associated with plumbing systems, while ferrous materials could engage in galvanic corrosion when coupled with ferrous fittings. Copper, while it is a non-ferrous material, is somewhat specific and may not be used universally across all removables like nuts or bolts compared to other non-ferrous options. Therefore, the emphasis on non-ferrous materials is central to maintaining reliable and effective plumbing systems.