The Nord Stream pipeline was designed and built according to the certifying body’s Offshore Standard DNV OS-F101 for Submarine Pipeline Systems. At the start of operation in October 2012, DNV GL issued the initial certificate which confirmed full compliance of the Nord Stream pipeline with the requirements of the Standard. During the five years that followed, Nord Stream’s engineers and DNV GL’s experts worked closely on the development of Nord Stream’s pipeline integrity management system, verification, and monitoring of its operating and maintenance procedures. They exchanged technical information and regular reports, resulting in positive annual assessments and in DNV GL commending Nord Stream AG’s commitment to safe and reliable gas transportation.