Let's say some machine, whatever it does, has some number of "cycles" that indicates the machine is prepared for maintenance, let's say it is 15,000 cycles.

Is there a term that indicates that machine is approaching its limit? Something like "85% to ___" or "85% of ____"?

Edit: To clarify, this is actually in reference to a part of a machine that requires preventative maintenance.

  • "The Check Engine light keeps coming on."
    – Hot Licks
    Commented Oct 31, 2016 at 21:49
  • In aviation the "MTBO" (Mean Time Before Overhaul) is used. Many aircraft engines have a 2000 hour MTBO.
    – Jim
    Commented Oct 31, 2016 at 23:15
  • An engine which is close to or over its MTBO is said to be run-out.
    – Jim
    Commented Oct 31, 2016 at 23:22
  • I would say that the machine is 85% through its maintenance cycle. Commented Nov 1, 2016 at 0:46
  • I would say the machine has 15% time before maintenance/overhaul/service/teardown remaining.
    – Jim
    Commented Nov 1, 2016 at 5:59

4 Answers 4


Capacity is the term you are looking for;

​> - the total amount that can be contained or produced, or (especially of a person or organization) the ability to do a particular thing.

Cambridge Dictionary

The machine is running/producing at 85% of its capaciy and is approaching its full capacity level.

  • I think this is the best option, then would "85% of capacity" tend to make sense?
    – pay
    Commented Oct 31, 2016 at 20:28
  • Yes, 85% of its (full) capacity.
    – user66974
    Commented Oct 31, 2016 at 20:48
  • 2
    Capacity is used to measure throughput. IF the machine can produce 100 widgets an hour then if the machine were running at 85% capacity it would be producing 85 widgets per hour. I think OP is asking about maintenance schedule intervals. The machine can still be operating at 100% capacity but will be nearing a scheduled maintenance point. MTBS (Mean Time Between Service) MTBPM (Mean Time Between Preventive Maintenance) etc.
    – Jim
    Commented Oct 31, 2016 at 23:23
  • Agree with @Jim re capacity being something else entirely. He is absolutely right. Commented Nov 1, 2016 at 0:47

This is what people in industry call an operating envelope. My link comes from a glossary of Oil and Gas Drilling terms, where it is defined as:

Limited range of parameters in which operations will result in safe and acceptable equipment performance.

The term is used in other industries as well, especially aviation, where knowledge of the operating envelope of an aircraft can become a matter of life and death.

Using your example, you can say, "This machine is at 85% of its operating envelope."

  • 2
    An operating envelope defines variations of operating parameters that are acceptable for operation. Time between overhauls/maintenance is typically not part of the operating envelope. books.google.com/…
    – Jim
    Commented Oct 31, 2016 at 23:27
  • 1
    Agree with @Jim re operating envelope being something else entirely. He is absolutely right. Commented Nov 1, 2016 at 0:48

How about:

The machine is 85% of the way through its scheduled maintenance cycle?

The machine is 85% of the way through its preventive maintenance cycle (or schedule)?

For scheduled maintenance and preventive maintenance cycles, see Wikipedia, Maintenance, repairs, and operations.


This isn't a technical term, but you could say

life expectancy

"85% of its life expectancy"

All the definitions I found refer to humans, but I have seen this used for objects.

  • You beat me to it.
    – Phil Sweet
    Commented Nov 1, 2016 at 4:26

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