Availability Score according to OEE Overall Equipment Effectiveness

What is availability plant uptime


In this article, you will learn what is Availability Score related to OEE Overall Equipment Effectiveness and lean manufacturing activities. Also known as plant uptime.

Availability Score, [Plant Uptime] Definition

Plant Availability Score means the period of time that an operation or particular equipment is able to perform its intended task.

In fact, it is the amount of operational time of a machine or process that can directly impact the performance of a plant.

Availability is often measured by looking into a process’ uptime – that is the amount of time that the machine is performing work.

To characterize the availability of an asset, it is therefore important to identify the instances of downtime or any duration when operations are stopped. Downtime can be classified as planned or unplanned.

The uptime is calculated by taking the difference between the planned production time and the total duration of the downtime events that occurred during the planned production period.

Plant Uptime is a process or production performance measure or KPI which is used extensively in many industries as an alternative or together with plant downtime.

How to Calculate Availability Score

Availability Score is defined as the ratio of Run Time to Planned Production Time:

Availability Score = Run Time / Planned Production Time

In fact, Run Time is simply Planned Production Time minus the Stop Time,

Stop Time is calculated as the whole time where the manufacturing process was supposed to be working but was on-hold because of Unplanned Stops (e.g., Breakdowns) or Planned Stops (e.g., Changeovers).

Run Time = Planned Production Time − Stop Time

It is sometimes referred to as plant downtime because it incorporates all the possible downtime causes both scheduled and unscheduled therefore representing the time that the plant is actually up and running producing value-added goods for customers.

In the end, this is the time the production line or process is making money for the business.

Plant Uptime or plant availability is also a component in calculating plant and process OEE.


The availability score measures the uptime of a machine or process against the planned production time.

As one of the factors of Overall Equipment Efficiency (OEE), Availability is expressed as a percentage.

The OEE formula is considering the multiplication of the availability score, performance score, and quality score and is represented by a percentage.

OEE = Performance Score  x  Availability Score  x  Quality Score

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REFERENCES: Plant Uptime Availability Score.






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Ramon Cayuela, MS, BS, Chemical Engineering

CIQA President and CEO.
I've been working in validation engineering since 1992 with many multinational pharmaceutical companies. I love sharing my passion and knowledge with others. If you have any questions about anything (or just have general questions). I will be more than happy to assist you. You can count on the BEST customer service on CIQA. I go to great lengths to make sure my clients are 100% satisfied with their purchases and check emails/messages consistently throughout the day. You can rest assured that everything being sold here is as-described or your money back. I look forward to working with you!