The application of subsea technology in the offshore oil and gas industry demands large capital investments and significant operational expenditures. The value of using subsea technology depends on its production availability (see 3.17) which is a reflection of its reliability and maintainability (RM). This API recommended practice (RP) aims to provide operators@ contractors and suppliers with guidance in the application of reliability techniques to subsea projects within their scope of work and supply only. It is applicable to: ?? standard and non-standard equipment@ ?? all phases of projects from feasibility studies to operation. This RP does not prescribe the use of any specific equipment or limit the use of any existing installed equipment or indeed recommend any action@ beyond good engineering practice@ where current reliability is judged to be acceptable. It is also not intended to replace individual company processes@ procedures@ document nomenclature or numbering; it is a guide. However@ this RP may be used to enhance existing processes@ if deemed appropriate. Users of this RP should gain a better understanding of how to manage an appropriate level of reliability throughout the life cycle of their subsea projects. Industry wide@ users should be able to: ?? recognize the trade off between up front reliability and engineering effort vs. operational maintenance effort@ ?? provide better assurance of future performance of subsea systems@ ?? effectively manage the risks from using novel equipment and standard equipment in novel applications@ ?? schedule projects with sufficient time to address all the technical risks. Overall@ this should lead to better understanding of technical risk and@ therefore@ greater confidence in economically or technically challenging developments. Furthermore@ this RP provides the industry with a common framework and language@ compatible with ISO 20815@ Petroleum@ petrochemical and natural gas industries??Production assurance and reliability management@ for the specification and demonstration of reliability achievement between operators@ contractors@ and suppliers. Reliability is a topic which is best addressed through industry wide cooperation in terms of best practice@ managing failures that do occur and the collection and analysis of performance data. This RP aims to provide a starting point for developing common understanding and cooperative progress within the subsea oil and gas industry. The achievement of improved subsea equipment availability requires good engineering and management processes@ practices and behaviors at an organizational level to manage and minimize the potential for equipment failure. The focus of this RP however@ is on specific activities (or tasks) that can be implemented within projects to achieve immediate and tangible improvements to system performance.