api 5000API 6A - Type - 6B 34.5 MPA (5000 psi) API 6A - Type - 6BX 13.8 MPA (2000 psi)Api 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