All positive pressure supply systems shall be provided with duplex line pressure regulators piped in which configuration?

The correct response indicates that all positive pressure supply systems require duplex line pressure regulators to be piped in a parallel configuration. This configuration is essential because it allows for redundancy and ensures a continuous supply of gas. When two regulators are configured in parallel, one can operate while the other serves as a backup. If one regulator fails or requires maintenance, the other can seamlessly take over, preventing interruptions in service, which is crucial in medical settings.

In a parallel configuration, both regulators receive the same supply pressure and are capable of supplying the line independently. This design is important for maintaining the integrity and reliability of positive pressure systems used to deliver medical gases, where consistent pressure and flow are critical for patient care.

Other configurations such as series or loop are not suitable in this context because they do not provide the same level of redundancy or reliability. In series, regulators would have to operate sequentially, which could lead to a complete loss of pressure if the first regulator fails.