Page 263 - Design of Simple and Robust Process Plants

References 249
Reliability R(t) is the probability that a component or system performs its function
over a time interval 0±t, given that the component or system was to be considered
new at time zero.
Unavailability U(t) is defined as U(t) = 1 ± A(t)
Unreliability F(t) is the probability that a component or system fails during the time
interval (0, t) given that the component or system was to be considered new at time
zero:
F(t) = 1 ± R(t)

Notation
A(t) availability
f(t) proportion of items failed in time interval
F(t) unreliability
n the number of items or samples
N total number of items on test
P probability of overall system
p probability of component
U(t) unavailability
R(t) reliability
t time
x random variable
b Weibull parameter shape parameter
k failure rate
g Weibull parameter scale parameter
x failure occurrence rate

References

Center for Chemical Process Safety (CCPS) Henley, E.J. and Kumamoto, H. Probabilistic
Guideline for Process Equipment Reliability Risk Assessment: Reliability Engineering
Data with data tables. AIChE, 1989. Design and Analysis. IEEE Press,
Center for Chemical Process Safety (CCPS) New York, 1992.
Guidelines for Chemical Process Quantitative International Electrotechnical Commission
Risk Analysis of AIChE. AIChE, New York, (IEC). Standard IEC 61508.
1989. ISBN 0-8169-0402-2. Koolen, J.L.A., Sinke, D.J. and Dauwe, R.
Clockwork Designs Inc., Spicewood Springs Optimization of a total plant design
Road, Ste 201, Austin, TX 78759, USA. Escape-9. Computers Chem. Eng. 1999,
Dubi, A. Analytic approach and Monte Carlo 23(Suppl.), S31±S34.
methods for realistic systems analysis. Leitch, R.D. Reliability Analysis for Engineers:
Mathematics and Computers in Simulation An Introduction. Oxford University Press,
1998, 47, 243±269. 1995. ISBN 0-19-856371-X.
Henley, E.J. and Kumamoto, H. Reliability Malchi Science Dubi A, Ltd., 39, Hagalim
Engineering and Risk Assessment. Prentice- Boulevard, Herzliya 46725, Israel. E-mail:
Hall, Inc., 1981. ISBN 1-013-772251-6. spar@bgumail.bgu.ac.il