The scale range of positive pressure analog indicators shall have the normal reading fall within the _________ percentage of the gauge scale.

The correct choice indicates that the normal reading for positive pressure analog indicators should fall within two-thirds of the gauge scale. This standard ensures that the gauge provides an adequate range for clinicians to monitor the pressure levels effectively.

By having two-thirds of the scale dedicated to the normal operating range, it allows for sufficient room to address variations and fluctuations that can occur during typical system operations. This approach enhances the reliability and accuracy of readings, confirming that operators can easily observe any deviations that might signify a need for intervention or maintenance.

In medical gas systems, maintaining accurate pressure readings is crucial for ensuring patient safety and system integrity. The selected standard helps provide clear visibility into operational pressures, enabling healthcare providers to respond appropriately to any changes.

Other options don't provide the same level of assurance. For instance, a narrower range might not account for potential variations, leading to potentially dangerous situations where pressure changes go unnoticed. Therefore, adhering to the two-thirds guideline ensures optimal performance and safety in medical gas systems.