At the firm Dalsem in Den Hoorn glass houses are designed and produced for over tens of years for the “high-tech” horticulture(?). In this branch, among others, (welded) stealconstructions, which are manufactured in own production halls, must be provided by the 1-7-2014 obligated CE-mark. LAB Verduyn BV was asked to provide for the whole certification of all required welding methods and welder-qualifications.