Choke and Kill System Requirements The requirements in this section are for choke and kill systems used on offshore installations. The equipment shall be fabricated from carbon, low alloy or martensitic steel. It shall have a minimum product specification level PSL 2 and material class DD as specified in API Specification 6A. It must also be rated for use under the service conditions delineated in this section. Rated Working Pressure and Sizes for Connections The flanged, studded and hubbed connections on the equipment to be supplied in accordance with this specification shall be type 6B or 6BX connectors as defined in API Specification 6A. The flanged, studded and studded-to-hubbed connections shall be furnished with ring gaskets in accordance with API Specification 6A. Type R and type RX gaskets are interchangeable in flanged connections with ring grooves. Only type BX gaskets will fit in flanged connections with ring holes. The studs and nuts used to fasten the pressure-containing parts and end connections on equipment to be supplied in accordance with this section are required to have corrosion resistant washers. The flange connections on the equipment to be supplied in accordance to this specification may have corrosion resistant overlays in ring grooves, as provided for in API Specification 6A. The overlays shall have a chemical analysis that complies with the manufacturer’s written specification. The mechanical properties of the overlay materials shall meet the minimum tensile and Charpy V-Notch impact requirements.