Availability and Downtime

Downtime Fraction

The downtime fraction uses the same cycle denominator.

highlighted = computed this step

Downtime Fraction

Downtime fraction is repair time divided by the same cycle.

downtime fraction=MTTRcycle\text{downtime fraction} = \frac{\text{MTTR}}{\text{cycle}}
Availability ratiosThe table shows uptime and downtime shares of the cycle.availability and downtime fractionscyclefractionavailability504/5downtime501/5

Downtime Value

Downtime fraction is 1/5.

10/50=1/510 / 50 = 1/5
Maintenance availabilityThe chart shows uptime and downtime shares in the deterministic cycle.maintenance availabilitycycle 50; availability 4/5; downtime 1/5caseMTBFMTTRcycleavailabilitydowntimebase4010504/51/5what-if405458/91/9baseup 40down 10cycle 50what-ifup 40down 5cycle 45what-if MTTR 5; availability gain 4/45deterministic two-number availability arithmetic only