Definition of reliability and maintenance concepts in oil and gas – validity aspects

Abstract

International standards have a key role in establishing consistent terminology. Amongst these is the recently published and revised ISO standard on reliability and maintenance data collection and exchange, i.e. ISO 14224:2016. This particular standard guides the petroleum, petrochemical and natural gas industries on how to achieve quality data for decision-making. It represents a main reference document for these activities and strongly influences how key terms are interpreted and used in practice. To serve this purpose, it provides a glossary that defines basic concepts or terms within the reliability and maintenance discipline, including new definitions of the key terms ‘safety critical equipment’ and ‘uncertainty’. This article addresses the new definitions given in ISO 14224:2016 and, in particular, the two mentioned above. A common understanding of the concepts is important from an analysis perspective, as it strongly influences the way both reliability and risk are assessed, managed and communicated. Some clarification of the meaning of each definition is proposed, and comparisons with definitions from other international standards are made, such as the definition of ‘uncertainty’ given in ISO 31000:2018. A main purpose of the article is to discuss the validity of the definitions with reference to different sub-criteria that should be satisfied, and provide recommendations concerning the use of the concepts and definitions studied.