Handbook of Reliability, Availability, Maintainability and Safety in Engineering Design - Part 44 studies the combination of various methods of designing for reliability, availability, maintainability and safety, as well as the latest techniques in probability and possibility modelling, mathematical algorithmic modelling, evolutionary algorithmic modelling, symbolic logic modelling, artificial intelligence modelling, and object-oriented computer modelling, in a logically structured approach to determining the integrity of engineering design. . | Theoretical Overview of Availability and Maintainability in Engineering Design 413 Average output rate 1 x x x x x x x x x It must be noted that this average output rate is expressed as a percentage of the possible output that can be achieved at maximum design capacity and 100 utilisation. It is thus an expression of the output capability of the plant as a whole depending on the percentage capacity for each state of the plant as a result of the states of each individual system multiplied by its availability. The above example of the simple three-system plant is insightful as an introduction to a plant having several states in which outages are regarded as full outages. If however the system outages are such that over a specific period of time T the systems could experience full outages as well as partial outages that are limited to 50 of system output then a table similar to the previous state matrix can be developed. To calculate the expected or average output rate of the plant over an operating period T the percentage capacity of MDC for each state during the shift period T is multiplied by the equivalent availability of each system. The partial state matrix given in Table presents the possible states of each system over a period of time T. These states are either 100 down full outage or 50 down partial outage . Table Double turbine boiler generating plant partial state matrix Period T Period T In period T In period T MDC 1 Up Up Up 100 2 Up Up Down 50 75 3 Up Up Down 100 50 4 Up Down 50 Up 75 5 Up Down 100 Up 50 6 Down 50 Up Up 50 7 Down 100 Up Up 0 8 Down 50 Up Down 50 50 9 Down 50 Up Down 100 50 10 Down 50 Down 50 Up 50 11 Down 50 Down 100 Up 50 12 Down 50 Down 50 Down 50 50 13 Down 50 Down 50 Down 100 25 14 Down 50 Down 50 Down 50 25 15 Down 50 Down 100 Down 100 0 16 Down 100 Down 100 Down 100 0 414 4 Availability and Maintainability in Engineering Design If for .
