What is the term 'dead leg' in piping systems?

The term 'dead leg' in piping systems refers specifically to a segment of pipe that is not flowing or used, which can lead to stagnation. This stagnant section poses several issues: it can allow for the accumulation of sediment, the growth of bacteria, or the degradation of the contents within the pipe due to lack of movement. These concerns are particularly significant in various applications, such as potable water systems, where stagnation can lead to contamination. It is crucial for system design to minimize dead legs to ensure efficient flow, prevent contamination, and maintain overall system integrity.

The other definitions provided do not accurately capture the concept of a dead leg. A constant flow of fluid does not describe stagnation, and a pipe segment filled with air is not the same as an unused section of piping. Similarly, a portion of the system used exclusively for testing usually implies that the section is active during testing, contradicting the principles of a dead leg.