Use of Reliability Engineering Tools to Enhance Subsea System Reliability
Authors: Wabnitz Frank , Netherland Houston 
Published: October 2008

Abstract
As the subsea industry moves into deeper waters, technical challenges and associated risks increase with significantly amplified failure costs. Other industries are in similar situations, using either complex and/or remotely operated equipment, requiring highly reliable systems and processes. This paper looks across industry boundaries, gives an overview of some of the mature reliability engineering techniques as they have been developed and used by these industries, and addresses their application to the subsea industry. The paper will enhance the understanding of these concepts and present examples of areas in the subsea industry to apply them.

Introduction
FMC sponsored a 6-month research program to explore values and benefits of reliability engineering tools and to develop a path forward. As a first step, mature industries, such as aerospace and automotive, were queried with respect to the use of reliability engineering as a discipline, and benchmarked. In addition, oil companies and FMC locations worldwide were surveyed regarding reliability requirements and their use of reliability engineering tools. As a result of this research, FMC made a commitment to implement reliability as an integral part of the development process to identify and reduce risk during the early life cycle stages. Reliability engineering resources were added and a global reliability program has been developed with the dual objectives of optimizing performance and minimizing overall system life cycle cost. Some initial research results and examples of reliability engineering work have previously been presented to the subsea community. One often mentioned â?" and often overestimated â?" roadblock for reliability engineering, the lack of numerical reliability data, has driven FMC to deploy risk assessment tools which aid design decision-making even without a wealth of numerical data. Today, FMC is empowering its in-house engineers to perform reliability tasks on their projects using these tools as integral part of their work. A discussion of some of these tools follows, including examples and benefits to subsea industries.

Failure Mode, Effect and Criticality Analysis
This section explains the concept, the requirements, and the use of Failure Mode, Effect, and Criticality Analysis (FMECA) followed by an example from the subsea industry.

Concept
The main objective for a FMECA is the same as for most reliability engineering tools: to support the design decisionmaking process. The design object can be a product or a process. A FMECA is a structured approach to examine potential failure modes and to determine the impact of failures on product operation during field use or to identify and correct process problems prior to first execution. Normally, this type of analysis is performed by a team of subject matter experts from various areas. A facilitator, either the design engineer responsible for the reliability or the reliability engineer, works with other team members who represent critical functions like maintenance, technical support, operations, and others, and provide insight from their areas of expertise. The FMECA allows the team to identify possible problems which could develop as a result of system failures.