Which method is used after installation tests to ensure that no cross-connection exists in the system?

The method involving individual pressurization or pressure differential is essential for confirming the integrity of a medical gas system post-installation and ensuring that no cross-connections exist. This approach entails pressurizing each zone or segment of the system individually and monitoring the pressure levels. By doing so, technicians can check if there is any unintended pressure equalization between different gas systems, which would indicate a cross-connection.

If a segment maintains its designated pressure without equalizing with adjacent systems, it confirms that there are no leaks or cross-connections. This method is particularly effective because it directly tests the physical properties and behavior of the gas within the system under controlled conditions. In a medical gas environment, it is critical to ensure the integrity of each gas line to prevent contamination that could jeopardize patient safety.

Other methods like visual inspections, leak detection, and gas analysis provide valuable information for overall system safety and functioning but do not effectively isolate and confirm the integrity of individual gas lines from cross-connections. Thus, individual pressurization or pressure differential stands out as the most reliable and specific method in this context.