PURPOSE This recommended practice (RP) is intended to provide accurate information that can serve as a guide for selection@ installation@ testing@ and operation of diverter equipment systems on land and marine drilling rigs (barge@ platform@ bottom-supported@ and floating). Diverter systems are composed of all subsystems required to operate the diverter under varying rig and well conditions. A general description of operational procedures is presented with suggestions for the training of rig personnel in the proper use@ care@ and maintenance of diverter systems. WELL CONTROL Opinions differ throughout the drilling industry concerning well control involving shallow gas. Appendix A of this publication is intended to provide some technical understanding of what takes place when shallow gas is drilled and to promote a better understanding of the analysis technique fundamentals. This publication@ API RP 64@ serves as a companion to RP 59 Recommended Practice for Well Control Operations and RP 53 Recommended Practice for Blowout Prevention Equipment Systems for Drilling Wells . RP 59 establishes recommended operations to retain pressure control of the well under pre-kick conditions and recommended practices to be utilized during a kick. RP 53 establishes recommended practices for the installation and testing of equipment for the anticipated well conditions and service. DEEPWATER Operations in deepwater have special requirements with respect to well control and well control systems. This publication discusses some of the special considerations with respect to diverter use in deepwater. The International Association of Drilling Contractors (IADC) has addressed diverter issues in the overall context of deepwater drilling in their publication IADC Deepwater Well Control Guidelines published in 1998. LOW TEMPERATURE OPERATIONS Some drilling operations are conducted in areas of extreme low temperatures. Since current general practices usually result in protecting diverter systems equipment from that type environment@ an applicable section has not been included for that service. GENERAL Recommended equipment installations@ arrangements@ and operations as set forth in this publication are deemed adequate to meet specified well conditions and intended uses. Examples presented herein are simplified embodiments and are not intended to be limiting or absolute. These recommended practices were prepared recognizing that alternative installations@ arrangements@ and/or operations may be equally as effective in meeting well requirements and promoting safety of drilling personnel@ public safety@ integrity of the drilling equipment@ protection of the environment@ and efficiency of ongoing operations.