api 5000API Blind Flanges dimensions are desned to handle hher rated pressure. We are an API 6a flanges manufacturer. Visit now! For Domestic (for India) Email: sales3@ Phone: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