API RP 53

The purpose of these recommended practices is to provide accurate information that can serve as a guide for installation of blowout prevention equipment systems on land and marine drilling rigs (barge, platform, bottom-supported, and floating). Blowout prevention equipment systems are composed of all systems required to operate the blowout preventers under varying rig and well conditions. These systems are namely - blowout preventers, kill line, choke manifold, closing unit, diverter, marine riser, and auxiliary equipment. The primary functions of these systems are to confine well fluids to the wellbore, provide means to add fluid to the wellbore, and allow controlled volumes to be withdrawn from the wellbore.