Project (T&C) testing & commissioning is the process of assuring that all systems and components of a building or  plant are designed, installed, tested, operated, and maintained according to the operational requirements of the owner or final client. A commissioning process may be applied not only to new projects but also to existing units and systems subject to expansion, renovation or revamping.

In Practice, DNP Systems (T&C) process comprises the integrated application of a set of engineering techniques and procedures to check, inspect and test every operational component of the project, from individual functions, such as network and equipment, up to complex such as modules, subsystems and systems.