For APM 1.0 we thought it was. Making sure mechanical equipment was available was the holy grail. But, thinking forward to APM 4.0, we had to step back and rethink! Is equipment being available enough? I do not think so. Mechanical or process related, rotating or fixed, or even mobile such as trucks, that piece of equipment must be doing what it is supposed to be doing for all of its lifecycle.
What does “doing what it is supposed to be doing” mean, isn’t that just reliability? Merriam Webster says “reliability is the quality or state of being reliable” – sounds a tad circular to me and does not help us much. But Merriam does go on to say reliability is “the extent to which an experiment, test, or measuring procedure yields the same results on repeated trials.” Well, that helps a little more, but it still does not give the most useful insights into what we expect for reliability in industrial equipment. Reliabilityweb.com helps here with this definition: “Reliability is a measure of the probability that an item will perform its intended function for a specified interval under stated conditions.” Such a definition is much closer to what is interpreted for APM 1.0.
“Reliability is a measure of the probability that an item will perform its intended function for a specified interval under stated conditions.”
Plus, to give Reliabilityweb.com credit, it does go on to define availability as an operations parameter – the percentage of time the equipment is available. Also, accordingly it suggests reliability is bounded by two measurable parameters:
- Mean Time Between Failure (MTBF): defined as: total time in service / number of failures
- Failure Rate: defined as: number of failures / total time in service
That’s good except that when the bulk of failures are caused by time-random process-induced degradation and not by simple wear-and-tear. Mean time is then elusive and MTBF is not an easily measurable parameter.
As a result, I do not like to talk reliability, because it’s not the measure of what we are really trying to achieve. We want to assure Availability to Plan, which implies the equipment is available for all the time the plan calls for it, and during that time it is able to perform its full intended duty. As a result, a large piece of critical equipment may be required to be fully operational, providing its full intended processing duty for the 4 years between turnarounds.
What is full intended processing duty? That will be different across diverse equipment types. But APM 4.0 is sensitive to this distinction. Not only must the pump be available, but it must provide the discharge pressure at the level required to participate fully in the chemical processes in which it is engaged. A distillation column must provide the absolute separation between the different draw offs at the specified heat input and heat withdrawal at the proper energy efficiency, so that the manufacture of each product component matches the quality and yield required by the plan with no extra waste.
Equally for all assets it’s not just bottom-up decisions on how we maintain assets for availability, but it must account for the top-down operational requirements to match the overall production goals.
Equally for all assets it’s not just bottom-up decisions on how we maintain assets for availability, but it must account for the top-down operational requirements to match the overall production goals. The required availability must synchronize with and reflect planning decisions, including changes in the plan for example due to deviations in logistics, and even weather fluctuations, or shipping delays. It means understanding, executing, and adjusting the quality and yield goals that are set for process assets and reacting precisely to errant behavior likely to spoil yield or quality. All such interactions assure collaboration between functional groups in a manufacturing process and between the applications that adjust and automate manufacturing functions. Indeed, the process operational dimension is a higher goal and is so important to include in all equipment reliability and availability discussions.
In the end APM 4.0 assures that, across the asset lifecycles, planning, operations and maintenance interoperate while simultaneously managing the risk and cost of asset decisions for the best possible outcomes. Our promise is that AspenTech will meet you wherever you are on your APM journey and help you along the way to improve both overall equipment effectiveness and operational excellence. To learn more, visit our solutions page.
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