Inherent Availability and Reliability with Greg Perry
We’re privileged to have the Capacity Assurance Consultant for Fluke Reliability Solutions, Greg Perry. He has two decades worth of experience in the industry. So he will be talking about what availability and reliability are.
We will tackle:
- What are availability and reliability
- What are the inherent availability and inherent reliability
- Do companies confuse inherent versus the actual values
- And much more!
What is availability?
Availability is the capacity for which the equipment or system can perform its original function when needed. Also, the percentage of its availability is essential. There are different definitions of availability, such as:
- Inherent availability
- Achieved availability
- Operational availability
What is reliability?
Reliability is somewhat like availability. It also measures whether a system can perform its function. But, reliability has a broader scope. It plays a more significant role in impacting the business’s performance. Reliability ensures all aspects, other than assets, are functional.
What are inherent availability and inherent reliability?
Inherent reliability is to the left of the potential failure (PF) curve. Meanwhile, inherent availability is to the right of the PF. That’s because you inherited the demerited new value. It’s also referred to as the maintainability state. You cannot do anything within the inherent availability realm to restore what you lost in the inherent reliability space. You’re never going to build to increase it. So, you need to improve failure modes rather than mitigate them, as is the case with inherent availability.
Even if you believe you have the perfect system, some failures would still occur. You have to take into account design for reliability and maintainability. These two work in balance to create capacity assurance.
Do companies confuse inherent versus the actual values?
Most companies do not know that there is even a difference. That could be due to them not understanding what the term inherent means. But once you use the curve to explain the concept, then they start to see it.
How does understanding the inherent versus achieved or operational availability relate to reliability?
For reliability, you need to understand what you can do from a holistic process. You need to ensure you address safety with the inherent reliability. From a capacity assurance angle, a safer scenario is more reliable. It doesn’t mean it’s available.
Do organizations need to measure availability and reliability?
For this, organizations look at the mean time between failures. As a result, you’ll be referring to failure modes rather than failure codes. Reliability lies more on code than a modal approach. Measuring availability relies on corrective. Keep in mind that everything on the PF curve is corrective. So all PMs, all PM routes, all condition monitoring, among others, are corrective.
You can’t derive a reactive work order categorization from a known maintenance strategy. You can also call a maintenance strategy a preventive action plan. Let’s say you’re looking to find out the total downtime, or repair time. With a system that can identify a work request, there’s the time the work request came in until it got approved. From there, it becomes a work order ticket. That request time created the ticket to start the clock. You’ll then get timed on how long it takes you to mitigate or end the failure. From start to finish, you should include processes like triaging, staging, and scheduling. Documenting all these stages falls under rent time. Add that to total response time, and you have the entire repair time. For this example, you’re only looking for full repair time on correctives.
Reactive work types include issues classified as a random bathtub curve. It’s both the before and after functional failures. By finding out the number of hours an asset should function, you’ll have a baseline. Total repair time then becomes a percentage of that full availability time. From there, you can get the percentage availability of that asset. It can get recorded daily, weekly, monthly, or even quarterly. You then get a better picture of how healthy your preventative actions are.
How do you calculate inherent availability or reliability?
That calculation is more of an asset design activity. Designers can use maintainability predictions, reliability predictions, and such. They’ll also use allocations to divide what they want. It could be more or less maintainability on reliability aspects. It’s not a manageable number to calculate. The higher the percentage of the capacity on the left of the DIPF curve, the longer the PF curve becomes. That will impact your PF interval.
What drives success when dealing with inherent measures?
The most significant success piece is understanding that there’s hope. You have to understand what the job entails and accept it. If you don’t believe it, you’ll create a different cultural behavior. These will have metrics that drive instead of guide specific actions. Going back to the basics will show you that it’s not as bad as you think. From there, you can look for ways to change the situation. Look at opportunities to the left of the PF to help you move.
How to change how people measure availability and reliability
Try and focus on what matters. Ensure you understand the business, the foundation, and its fundamentals. Most companies believe technology will bring about reliability and even capacity assurance. That won’t be possible without a foundational understanding of how things work. It would be best if you first learned the foundational tools.
It would help if you challenged the assumption. Get out there and find out for yourself what the actual standards could be. Don’t rely on what others say, especially when you doubt the outcomes based on what you see. It will surprise you how much you already know.
Greg Perry Links:
- Greg Perry Linkedin
- Fluke Reliability Services
- RCM Blitz
- CMRP Certification from SMRP
- ISO 55000
- Accelix LinkedIn Group
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