What is required for screwed cast-iron water fittings used in a water system?

Screwed cast-iron water fittings are critical components in plumbing systems, and their material and surface treatment are important for ensuring durability and preventing corrosion. The requirement for these fittings to be galvanized or cement-mortar lined is to protect them from the corrosive effects of water and the environment, thus prolonging their lifespan and ensuring they perform effectively within the water system.

Galvanization involves applying a protective zinc coating to the iron, which helps to prevent rust and degradation. Similarly, a cement-mortar lining provides a barrier that protects the cast iron from both internal corrosion caused by the transported water and external corrosion from environmental factors. This protective treatment is a crucial aspect of maintaining the integrity of the water system and ensuring that it operates safely and efficiently.

Options stating that they must be uncoated, painted, or can be any type of coating do not meet the specific requirements outlined in plumbing codes for ensuring the longevity and functionality of screwed cast-iron fittings in water systems. These alternatives do not provide the same level of protection against corrosion and other damaging factors, which is why they are not considered adequate. Thus, the necessity for galvanization or cement-mortar lining aligns with industry standards aimed at maintaining the quality and safety of plumbing installations.