Which term is used to describe openings in a tube not associated with tube enlargement?

Perforation is the term used to describe small openings or holes that occur in a tube's wall without a corresponding enlargement of the tube itself. These openings can occur for various reasons, such as corrosion, abrasion, or manufacturing defects. Unlike other terms, perforations do not lead to a significant change in the diameter or structure of the tube, making it a distinct classification used in the context of tubing and piping.

When considering the alternatives, leakage typically refers to the unintentional escape of fluid from a system, which can be associated with larger damages or defects, while fracture relates to a complete break in the material, resulting in separation rather than just openings. A cavity suggests a larger, hollow space within a material, which is not applicable to the specific context of small openings in a tube. Therefore, perforation is accurate in describing those defined openings that do not alter the overall size of the tube.