What is the primary purpose of an isolation valve?

The primary purpose of an isolation valve is to stop the flow of air in a pneumatic system, which allows for maintenance or repair work to be conducted safely and efficiently without disrupting the integrity of the overall system. Isolation valves are essential for isolating sections of the system that may need servicing, ensuring that other parts can continue to function properly while preventing unintentional release of pressure or airflow.

In this context, the other options present different functionalities that isolation valves do not primarily serve. Regulating air quality pertains more to filtration or treatment systems rather than flow control. Measuring airflow rates is handled by specific devices like flow meters or anemometers, not isolation valves. Enhancing system flexibility refers to the adaptability of the system design and components, which is influenced by various factors including component choice, but is not the primary function of an isolation valve.