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MTTF - Mean Time To Failure

A estimate of the average, or mean time until a design's or component's first  failure, (you may not want to include external failures), or disruption in the operation of the product, process, procedure, or design occurs. Mean time until a failure assumes that the product CAN NOT be repaired and the product CAN NOT resume any of its normal operations.

MTTF is related to items such as expected and/or operating life or other items that in general are not fixed or replacement even though it sometimes may be.

In a lot of design and components, MTTF it is especially near to the MTBF, (Mean Time Between Failures), which typically is a small amount longer than MTTF. This is due to the fact that MTBF includes the repair time of the designs or components. If a design or component works for an extended time, then it fails, is repaired in a reasonable amount of time, and then once again works for an extended time, the MTTF is the average, or mean, of the amount of time that it is in operational condition. The MTBF is the average time between failures to include the average repair time, or MTTR.

MTTR is not the correct tool for all applications, but is a useful measurement of reliability.

Also see MTTF - Mean Time To Failure, Design Life, Durability, Expected Life, Failure Rate, and R Reliability.

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Last Updated: Wednesday, 22-Mar-06 13:03:28 PST