Service life

Source: Wikipedia, the free encyclopedia.
This article is about the manufacturing concept. For the economic concept of service life, see Fixed capital.

British Rail Class 483 trains were 83 years old when they were withdrawn in January 2021; they were the oldest passenger trains in Great Britain remaining in regular passenger service at the time.[1][2]

A product's service life is its period of use in service. Several related terms describe more precisely a product's life, from the point of manufacture, storage, and distribution, and eventual use. Service life has been defined as "a

supported by its manufacturer.[citation needed
]

Service life is not to be confused with

mean time before failure (MTBF) or maintenance-free operating period (MFOP). Predicted life is useful such that a manufacturer may estimate, by hypothetical modeling and calculation, a general rule for which it will honor warranty claims, or planning for mission fulfillment. The difference between service life and predicted life is most clear when considering mission time and reliability in comparison to MTBF and service life. For example, a missile
system can have a mission time of less than one minute, service life of 20 years, active MTBF of 20 minutes, dormant MTBF of 50 years, and reliability of 99.9999%.

Consumers will have different expectations about service life and longevity[4][5] based upon factors such as use, cost, and quality.

Product strategy

Main article:
Product lifecycle management

consumable
, and service lives and maintenance activity will factor large in the service life. Again, an airliner might have a mission time of 11 hours, a predicted active MTBF of 10,000 hours without maintenance (or 15,000 hours with maintenance), reliability of .99999, and a service life of 40 years.

The most common model for item lifetime is the

product development. The middle portion of the bathtub, or 'useful life', is a slightly inclined, nearly constant failure rate
period where the consumer enjoys the benefit conferred by the product. As time increases further, the curve reaches a period of increasing failures, modeling the product's wear-out phase.

For an individual product, the component parts may each have independent service lives, resulting in several bathtub curves. For instance, a tire will have a service life partitioning related to the tread and the casing.

Examples

For maintainable items, those wear-out items that are determined by logistical analysis to be provisioned for

tires - failure to plan for this wear out item would limit automotive service life
to the extent of a single set of tires.

An individual tire's life follows the bathtub curve, to boot. After installation, there is a not-small probability of failure which may be related to material or workmanship or even to the process for mounting the tire which may introduce some small damage. After the initial period, the tire will perform, given no defect introducing events such as encountering a road hazard (a nail or a pothole), for a long duration relative to its expected service life which is a function of several variables (design, material, process). After a period, the failure probability will rise; for some tires, this will occur after the tread is worn out. Then, a secondary market for tires puts a retread on the tire thereby extending the service life. It is not uncommon for an 80,000-mile tire to perform well beyond that limit.[6]

It may be difficult to obtain reliable longevity data about many

actuarial analysis are not taken to the same extent as found with that needed to support insurance decisions. However, some attempts to provide this type of information have been made. An example is the collection of estimates for household components provided by the Old House Web[7]
which gathers data from the Appliance Statistical Review and various institutes involved with the homebuilding trade.

Some Engine manufacturers, such as for example Navistar and Volvo, use a so-called B-life rating,[8] based on the durability data of the engine manufacturer,[9] B10 and B50 index for measuring the life expectancy of an engine.[10]

When exposed to high temperatures, the

lithium-ion batteries in smartphones are easily damaged and can fail faster than expected, in addition to letting the device run out of battery too often. Debris and other contaminants that enter through small cracks in the phone can also infringe on smartphone life expectancy. One of the most common factors that cause smartphones and other electronic devices to die quickly is physical impact and breakage, which can severely damage the internal pieces.[11]

Operational life

For certain products, such as those that cannot be serviced during their operational life for technical reasons, a manufacturer may calculate a product's expected performance at both the beginning of operational life (BOL) and

end of operational life (EOL). Batteries and other components that degrade over time may affect the operation of a product. The performance of mission critical components is therefore calculated for EOL, with the components exceeding their specification at BOL. For example, with spaceflight hardware, which must survive in the harsh environment of space, the capacity to generate electricity from solar panels or radioisotope thermoelectric generator
(RTG) is likely to reduce throughout a mission, but must still meet a specific requirement at EOL in order to complete the mission. A spacecraft may also have a BOL mass that is greater than its EOL mass as propellant is depleted during its operational life.

See also

References

  1. ^ Clifton, Paul (4 January 2021). "Island Line bids farewell to "icon of transport"". Rail. Bauer Consumer Media. Archived from the original on 8 January 2021. Retrieved 8 January 2021.
  2. ^ Clinnick, Richard (4 January 2021). "Island Line bids farewell to "icon of transport"". RAIL. Archived from the original on 8 January 2021. Retrieved 8 January 2021.
  3. ^
    ISBN 9781889407005
    .
  4. ISBN 9780566088087
    .
  5. ^ "Drive it forever" Club Lexus Forums
  6. ^ Tire Retread Information Bureau
  7. ^ Old House Web, "Life Expectancy of Household Components
  8. ^ "Latest Articles".
  9. ^ "Latest Articles | Page 3".
  10. ^ "B10 & B50 Life of Diesel Engines".
  11. ^ "Life Expectancy of a Smartphone". Retrieved 26 May 2017.
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