This European standard specifies the construction, dimensions and marking of covered metal jacketed gaskets for use with flanges complying with prEN 1759-1 for Class 150, Class 300, Class 600, Class 900, Class 1500 for sizes up to and including NPS 24, and for class designation 2500 up to and including NPS 12. This European Standard does not extend to covered metal jacketed based heat exchanger gaskets with pass bars or large vessel gaskets but, in the lack of a dedicated document for such gaskets, the principles set down may be applied to them.