api5000The Api 5000 Flanges are manufactured using carbon steel or alloy steel, and they help to join pipes or block a section of the piping system. Api 10000 instrument flanges is of ring type joint specifically and they are not desnedAPI 5000, 10000 are used in reference to wellhead 'christmas tree' pressure ratings as well used for the wing valve, master valve ratings. There may be hher classes as