What is the purpose of a mandrel in pipeline testing?

A mandrel is a tool used during pipeline testing, particularly for flexible conduits, to measure excessive deflection. The purpose of the mandrel is to verify that the conduit is not deforming beyond acceptable limits. In flexible pipe installations, over time and due to various factors such as soil movement or live load conditions, the pipe may experience deflection. By inserting a mandrel into the pipe, operators can check for this deformation and ensure the integrity of the pipe, which is crucial to maintaining the system's proper function and preventing future failures.

The other functions, such as assessing pressure, determining flow rate, or inspecting the internal surface, are related to different tools and techniques used in pipeline testing and do not pertain to the role of a mandrel specifically.