api 5000API 6A - TYPE - 6B 34.5 MPA (5000 PSI). Size. B. OD. C. (MAX.) K. P. E. T. Q. X. BC. N. H 2) RING GASKET ACCORDING TO API 6AApi 6a Wn Flanges applications including pressure classes – 720 psi and 960 psi, the API specified no changes to the ASA B16.5 Standard, using the 300 lb. and 400 lb. flanges