Components for shutting in the drillpipe internally are a basic part of well control equipment. All drill string BOP valves must have a pressure rating equal to, or greater than, the BOP stack.
The following drill string BOP valves shall be available on the drill floor at all times:
- A full bore Kelly Cock shall be installed at the base of the kelly or top drive.
- A ball type stabbing valve, with connections or a cross-over to suit the workstring together with an operating handle for the valve.
- A circulating head with connections to suit the drill string.