api5000API 5000 (Class 1500) Connection Types Performance Requirement API 6A Flange Means; Studded; Bolted; PR1; PR2; American Petroleum Institute; Coating Types Of API STD 6A HhAPI Stands for American Petroleum Institute. API Socket Weld Flanges are manufactured to provide hh strength and robustness. These flanges are made for hh heat purposes. These