Reliability Maintenance Engineering Day 3 session 1 Measuring AvailabilityThree day live course focused on reliability engineering for maintenance programs. Introductory material and discussion ranging from basic tools and techniques for data analysis to considerations when building or improving a program.

1. Reliability Engineering
Fred Schenkelberg
fms@fmsreliability.com

2. MEASURING AVAILABILITY
Day 3 Session 1

3. Objectives
• Structuring a hierarchy of goals and measures
• Determining constraints and bottlenecks
• Developing five measures of availability
• Obtaining measures for critical equipment
• Embarking on structured approach to improve
availability.
• Formulating a condition monitoring program

5. Availability & Business
• Translating business
objectives into
availability
• Cost
• Yield
• Throughput
• ROI
• …

6. Hierarchy of Goals
• Business goals to line,
system, or process
• Decision & budget level
• Physical alignment
• Process alignment

7. Actionable level
• Apportionment
• RBD and apportionment
• Available
• Reliability
• Maintainability

8. Sample goal statements
• Line x in plant y operates
with 90% availability over
each shift
• Function
• Environment
• Probability
• Duration
• Compressor x on
equipment y provides z
pressure with 95%
reliability over 5 years of
continuous operation.
• Replacement of
compressor x occurs 90%
of the time in less than 2
hours with existing
equipment and
diagnostics.

9. Performance Reporting Flow

10. Discussion & Questions

12. Process flow modeling
• Map the process
including
• Physical item
movement
• Information movement
• Transitions, decisions
• Durations and gates

13. Constraints
A limiting factor
• Capacity
• Throughput
• Budgetary

14. Bottlenecks
: a delay caused when one
part of a process or
activity is slower than the
others and so hinders
overall progress
• Opportunity
• Optimization

15. Examples
• Bottling plant
• Filler equipment
– 600 per hour fill rate
– Lowest rate of all
equipment
• Buffer (inventory holding
area)
– Limited by size or floor
space

16. Discussion & Questions

18. Availability
• Ratio of the expected
value of uptime to the
aggregate of the
expected values of up
and down time.
A =
E[Uptime]
E[Uptime]+ E[Downtime]

19. Inherent Availability, Ai
• The probability of
satisfactory operation at
given point in time
under stated conditions
in an ideal support
environment.
• Downtime only counts
corrective maintenance
and does not include
– Logistics time
– Administrative time
– Preventative
maintenance
• Items under control of
equipment designer.

20. Achieved Availability, Aa
• Probability of
satisfactory operation at
given point in time
under stated conditions
in ideal support
environments
• Downtime only includes
active preventative and
corrective maintenance
time (wrench time).
• Does not include
– Logistics time
– Administrative time

21. Operational Availability, Ao
• Probability of
satisfactory operation at
given point in time
under stated conditions
with actual support
environment.
• Downtime includes
everything.
Reliability/
Supportability/ Maintainability/
Design “Cause”
Operational “Effect”
Operation
Logistics Maintenance
Time to
Support (TTS)
Time to
Maintain (TTM)
Time to
Failure (TTF)
System Downtime

22. Time

23. Discussion & Questions

25. Critical Equipment
• What to optimize?
• Bottleneck equipment
• Quality element
• ‘Where the magic
occurs’

26. Risk Minimization
• Long repair times
• Safety issues
– Explosion
– Releases
• Poor Quality impact

27. What to Measure
• Direct performance
• Performance indicators
• Quality stability
• Leading indicators
– Current
– Pressure

28. Measurement Techniques
• Product measurements
• Process parameters
• Process Control
• Inspections and Studies

29. Discussion & Questions

31. Availability Improvement Planning
• Assessment
• Process mapping
• Data collection
• Characterize current
state (and reason for
current state)

32. Level of detail
• Enough data to make
informed decisions
• Is the process stable?
• What causes
differences?
• What is cost of
downtime?

33. Focus on Value
• Select improvement
projects and tasks that
have highest ROI
– Low hanging fruit
– Major return potential
– Portfolio approach
• Estimate value and risk
before selecting tasks

34. Program Approaches
• Major redesign
• Incremental
improvements
• Process control
(stability)
• Backup plan

35. Discussion & Questions

37. Condition Monitoring
• Regular observations or
measures of indictors of
impending failure.
– Oil level
– Current draw
– vibration

38. Image from article by Ricky Smith on The Maintenance Phoenix site

39. Experiments, Models and Measures
• Start measuring today
• Engineering judgment
and experience to
starting monitoring
• Design experiments to
determine effective
predictors

40. Considerations
• Ability to detect fault
indicators
• Lead time requirements
– Spare parts
– Specialized equipment
• Scheduling optimization

41. Discussion & Questions

42. Summary
• Structuring a hierarchy of
goals and measures
• Determining constraints and
bottlenecks
• Developing five measures of
availability
• Obtaining measures for
critical equipment
• Embarking on structured
approach to improve
availability.
• Formulating a condition
monitoring program
Measuring Availability