GB/T 15171-2025 "Test Method for the Sealing Performance of Packages" specifies two core test methods for evaluating the sealing integrity of non-vacuum packages to address the diverse needs of the packaging industry. The first is the traditional "Underwater Bubble Test," which detects leaks by observing the formation of continuous bubbles in water within a vacuum chamber. This method is suitable for packages with water-resistant outer materials. The second is the newly added "Vacuum Decay Test," which precisely assesses sealing performance by monitoring changes in vacuum decay within a sealed test chamber, using a quantifiable "vacuum decay rate." This method is particularly suitable for products with stringent requirements for micro-leaks. The relevant testing instruments mentioned in the standard mainly include a vacuum chamber system (including a sealing cover, transparent container, etc.) for the underwater bubble test and a high-precision pressure sensor testing system for the vacuum decay test.