In pressure testing, what indicates that there may be a leak?

A decrease in pressure over time during a pressure test is a key indicator that there may be a leak in the system. In pressure testing, the goal is to maintain a specific pressure level for a designated period. If the pressure drops, it suggests that there is a breach or failure in the integrity of the system, allowing air or fluid to escape, which directly points to a potential leak.

This principle is crucial in many operational settings, including landfill management, where maintaining the integrity of containment systems is essential for environmental protection and compliance with regulatory standards. Detecting a leak early through pressure testing can prevent more significant issues that could arise from fluid or gas escape, such as contamination of surrounding soil and water resources.

The other options may signify issues, but they do not provide a definitive indication of a leak in the way a decrease in pressure does. In contrast, an increase in membrane temperature might be related to other factors, persistent sounds in the weld area could indicate different problems unrelated to leaks, and discoloration on welds might not directly correlate with a leak either.