Tutorial 4 - Reliability & RCM
1. Reliability is a measure of the probability of what for a device, system or plant item ?
2. Unreliability is a measure of the probability of what for a device, system of plant item
3. Explain why F{t) + R (t) = 0?
4. We are told that the probability of a pump not operating is 0.2345. What is its reliabi
5. Define Availability?
6. A small industrial plant buys 6 new pumps. It runs them all for 1 week (7 days). T
results were obtained:
Pump Results of Test Period
1 Failed on day 2, repair time 3 hours
2 Failed on day 1, repair time 1 hours
Failed on day 6, repair time 2 hours
3 Failed on day 1, repair time 4 hours
4 No failures
5 No failures
6 Failed on day 4, repair time 1 h our
Note: repair time was the time taken to get the pump working again.
Calculate:
a) Mean down time
b) Mean time between failures
c) Mean failure rate(per year)
d) Availability
7. A power utility has bought 200 acoustic sensors to measure partial discharge on a
During a 24 week trial, it recorded 15 failures, with the corresponding down times in
3, 6, 8, 2, 1, 4, 3, 3, 3, 6, 6, 7, 4, 3, 5.
Calculate:
a) Mean down
1. Reliability is a measure of the probability of what for a device, system or plant item ?
2. Unreliability is a measure of the probability of what for a device, system of plant item
3. Explain why F{t) + R (t) = 0?
4. We are told that the probability of a pump not operating is 0.2345. What is its reliabi
5. Define Availability?
6. A small industrial plant buys 6 new pumps. It runs them all for 1 week (7 days). T
results were obtained:
Pump Results of Test Period
1 Failed on day 2, repair time 3 hours
2 Failed on day 1, repair time 1 hours
Failed on day 6, repair time 2 hours
3 Failed on day 1, repair time 4 hours
4 No failures
5 No failures
6 Failed on day 4, repair time 1 h our
Note: repair time was the time taken to get the pump working again.
Calculate:
a) Mean down time
b) Mean time between failures
c) Mean failure rate(per year)
d) Availability
7. A power utility has bought 200 acoustic sensors to measure partial discharge on a
During a 24 week trial, it recorded 15 failures, with the corresponding down times in
3, 6, 8, 2, 1, 4, 3, 3, 3, 6, 6, 7, 4, 3, 5.
Calculate:
a) Mean down
