30 CFR §250.431

1. (a)Use diverter spool outlets and diverter lines that have a nominal diameter of at least 10 inches for surface wellhead configurations and at least 12 inches for floating drilling operations;
2. (b)Use dual diverter lines arranged to provide for downwind diversion capability;
3. (c)Use at least two diverter control stations. One station must be on the drilling floor. The other station must be in a readily accessible location away from the drilling floor;
4. (d)Use only remote-controlled valves in the diverter lines. All valves in the diverter system must be full-opening. You may not install manual or butterfly valves in any part of the diverter system;
5. (e)Minimize the number of turns (only one 90-degree turn allowed for each line for bottom-founded drilling units) in the diverter lines, maximize the radius of curvature of turns, and target all right angles and sharp turns;
6. (f)Anchor and support the entire diverter system to prevent whipping and vibration; and
7. (g)Protect all diverter-control instruments and lines from possible damage by thrown or falling objects.