After plan approval of an essential or important control and monitoring system is completed, DNV performs a certification survey at the manufacturer's premises.

In addition to witnessing normal operation and failure handling of the control system (as detailed in the approved test program), DNV also verifies that the hardware is installed in accordance with class requirements and that software developement is handled in a controlled manner in accordance with quality standards as specified in DNV rules.

The certification survey is normally carried out by qualified personnel at the local DNV office which is located closest to the manufacturer. However, for new and/or complex control systems is attendance of the responsible approval engineer also required.