Search results
Results From The WOW.Com Content Network
Operational availability is used to evaluate the following performance characteristic. For a system that is expected to be available constantly, the below operational availability figures translate to the system being unavailable for approximately the following lengths of time (when all outages during a year are added together):
The availability factor of a power plant is the duration it achieves production of electricity divided by the duration that it was planned to produce electricity. In the field of reliability engineering , availability factor is known as operational availability , A o {\displaystyle A_{o}} .
Availability, operational (Ao) [7] The probability that an item will operate satisfactorily at a given point in time when used in an actual or realistic operating and support environment. It includes logistics time, ready time, and waiting or administrative downtime, and both preventive and corrective maintenance downtime.
High availability (HA) is a characteristic of a system that aims to ensure an agreed level of operational performance, usually uptime, for a higher than normal period. [ 1 ] There is now more dependence on these systems as a result of modernization.
Availability means the probability that a system is operational at a given time, i.e. the amount of time a device is actually operating as the percentage of total time it should be operating. High-availability systems may report availability in terms of minutes or hours of downtime per year.
The Mil-HDBK-217 reliability calculator manual in combination with RelCalc software (or other comparable tool) enables MTBF reliability rates to be predicted based on design. A concept which is closely related to MTBF, and is important in the computations involving MTBF, is the mean down time (MDT).
Availability includes non-operational periods associated with reliability, maintenance, and logistics. This is measured in terms of nines. Five-9's (99.999%) means less than 5 minutes when the system is not operating correctly over the span of one year. Availability is only meaningful for supportable systems.
The Availability portion of the OEE Metric represents the percentage of scheduled time that the operation is available to operate. The Availability Metric is a pure measurement of Uptime that is designed to exclude the effects of Quality and Performance. The losses due to wasted availability are called availability losses. [5]