Design Life
The expect life of a product by design or
it's endurance, durability, or how long it
will perform while meeting the minimum specifications or customer
requirements. Can also be the length of time till t he product becomes
obsolete.
Could also refer to the life or endurance
of a process. Example, machine ware out, space
shortages, etc. The unit of measurement for design life could be expressed
in units of time such as years, hours, miles, cycles, etc. Should be based
on a baseline measurement.
A good example are light bulbs. Light bulbs
could be designed to last forever. But doing so would mean fewer light
bulbs produced, and would thus raise the cost of a light bulb to perhaps
well over 50% of the current cost. So if you were to break a light bulb or
install new lighting, it could cost $100 or more for each bulb unit.
Products could be tested using an accelerated
life test, (ALT) with MTBF,
(Mean Time Between Failure),
MTTF,
(Mean Time To Failure), and a Bathtub
curve.
