Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1275515
www . machinerylubrication.com | July - August 2020 | 7 ML A central component to plant reliability is iden- tif ying and managing the risk associated to the equipment within the plant. As one gets entrenched in the vast amount of technologies and methodologies to increasing the plant reliability, each possible effort must be judged by the analysis of the benefit and the cost associated to achieving that benefit. This cannot easily be done without an understanding of the equipment's propensity to fail. A failure might be a complete loss of productive function or could simply be a reduced productivity or exposed hazard to the surroundings. For the essential equip- ment in a plant, lubricated machines are of particular concern because they tend to represent the assets that have moving parts, which introduces more dynamic fail points. Or in terms of plant reliability, lubricated rotating equipment represents a subset of plant assets that are by default at higher risk. For this reason, reliability engi- neers often put an emphasis on risk analysis and risk mitigation on lubri- cated rotating equipment. ese efforts over the decades have resulted in many proven methods to narrow down which machines are most at risk, meticulously analyze the degree of risk and solutions to mitigate this risk. One way to better understand the concept of risk for lubricated machines is to see it as a product of two variables: (1) the probability of failure and (2) the consequence of failure. is can be analogous to a person standing on the edge of a cliff. Risk = The Proababilty of Failure x The Conse- quence of Failure First, the probability of a person falling off that cliff is characterized by questions such as: How close is he to the cliff? How steep is the slope at the cliff? Are there guardrails? Is this a young reckless person or is this a rock climber experienced with cliffs? Second, the consequence of failure can be characterized by questions such as: How high is the cliff? Are there rocks or deep water at the bottom of the cliff? Is there a safety net at the bottom? Is this person an experienced base jumper with a wingsuit? With this combination of questions, one can assess whether that cliff daredevil is at risk or not. e same types of questions can be asked for lubricated machines to assess their level of risk. Answering these questions are fundamentally what drives reliability-cen- tered maintenance (RCM). When RCM is done effectively, there is a deep under- standing of every relevant variable that can influence the plant's overall reliability and the goal of determining what can be done to maintain an optimized level of reliability. Considering these two variables of risk, the probability that a lubri- cated machine will fail is irrelevant if there is no consequence. Similarly, the consequence of failure is irrelevant if the machine cannot fail, theoretically speaking. e two must be understood to manage the risk. When putting this into practice, here are some questions that might be asked to identify the risk associated to lubricated machines. The Probability of Failure • How well are the lubricated machines equipped with sensors, sight glasses, oil analysis and other feedback indicators to alert lubrica- tion technicians of a potential failure mode? • How well-equipped are lubrica- tion technicians with the right tools and software? • How well-trained are the lubrica- tion technicians in lubrication best practices? • How experienced are the lubrication technicians in observing and miti- gating lubrication failure modes with proactive maintenance and predictive maintenance strategies. • How is the culture of the lubrica- tion team in promoting good lubrication practices and aiming towards continuous improvement? The Consequence of Failure: If the lubricated machine were to experience a failure… • How much does the replacement part cost? What is the availability of this replacement part? • How much labor would be required? Can this work be easily scheduled? • What is the time before this would impact produc- tion? What is the cost of this lost production? Are there backups to this machine? • What other machines could be damaged or also expe- rience a failure (as a chain reaction of failures)? • Is the safety of anyone compromised? If so, in what way? • Is the impact to the environment compromised? If so, in what way? Pareto Principle Have you ever taken a multiple-choice test where more than one possible answer was correct, but to get credit for the answer you had to choose the most correct answer? COVER STORY