What term describes a lump or mound of rust formed on a pipe surface?

The term that describes a lump or mound of rust formed on a pipe surface is "tubercule." Tubercules are typically formed in situations where water and metal interact over time, leading to localized corrosion. This phenomenon is often observed in water distribution systems, where stagnant or low-flow conditions can promote the development of these raised areas of corrosion, which can eventually affect the integrity of the pipe.

The formation of tubercules is significant because it can alter the flow characteristics of the water and potentially lead to more severe corrosion issues. Understanding this process is crucial for maintenance and the assessment of the condition of piping systems used in drinking water treatment.

While the other terms relate to corrosion or deposits, they do not specifically refer to the mounds or lumps that tubercules represent. An oxide refers broadly to a compound formed between oxygen and another element. A corrosion pit is a localized degradation that occurs at a specific point on the metal surface rather than a raised mound. Scale typically refers to mineral deposits that can build up on surfaces due to precipitation from water, which is distinct from the rust-related phenomena associated with tubercules.