By Aleksandar Pudar
Technical Superintendent and Planned Maintenance Supervisor at Reederei Nord BV
Co-founder of "Out of Box Maritime Thinker Blog" and founder of
Narenta Consilium Group.
2.7.1 DOCUMENTING
RCM ANALYSES
The RCM
analysis documentation serves multiple purposes that are critical to its
success. Firstly, it offers a basis for defence and enables management to
review and approve the RCM outcomes. Secondly, it provides regulators and
classification societies with a means of audibility. Thirdly, it establishes a
benchmark for system operation, which can aid in assessing the impact of changes
and executing other risk management activities. Fourthly, it preserves
institutional memory and captures the RCM team's expertise. Finally,
documentation guarantees the sustainability of the RCM program by allowing for
periodic updates based on real failure data and potential enhancements like new
condition-monitoring technologies. Failing to document the RCM analysis can
lead to costly and time-consuming updates, resulting in an outdated RCM program.
2.7.1 DOCUMENTING RCM ANALYSIS STEPS
It is
essential to record all analysis steps and related information to ensure thorough documentation of the RCM
analysis; each step should include the following:
·
Results of the
analysis step: The outcomes of each analysis step
should be clearly documented. This includes identifying the potential failure
modes, causes, effects, and recommended maintenance tasks or actions. The
documentation should be specific and concise, and any uncertainties or
assumptions made during the analysis should be noted.
·
Decision tools
used: Any decision tools used during the analysis,
such as risk matrices or decision trees, should be documented; this includes
noting the tool used, any assumptions made, and the results obtained. This
information can provide valuable context for future analysis and
decision-making.
·
Pertinent
information related to the step: Any relevant
information related to the analysis step should also be documented. For
example, whether specific equipment was excluded from the analysis or certain
failure modes were deemed less critical should be noted. This information can
be helpful in future analysis or for audit purposes.
By
documenting each analysis step thoroughly, organisations can ensure that the
RCM analysis is defendable, auditable, and adaptable to changes in equipment or
operating conditions. This documentation can also aid in training new personnel,
preserving institutional knowledge, and providing a foundation for continuous
improvement.
2.7.1.1
DEFINING SYSTEMS
It is
important to record the following information in either a tabular or paragraph
format to ensure comprehensive documentation of the
defining system step:
·
Description of relevant operating modes:
This includes a detailed description of the different operating modes for the
vessel, such as normal operation, standby, or emergency modes. This information
provides context for understanding the equipment and system functions during
various operating conditions.
·
Functional group breakdown and
boundaries: A breakdown of the vessel's functional groups should be documented,
along with the boundary for each group; this provides a clear understanding of
the different functions and subsystems on the vessel.
·
Functional group and equipment
partitioning: This involves partitioning the functional groups and equipment
based on their criticality to vessel operations. This information is crucial in
identifying which equipment requires maintenance and how often.
·
Decision tools/criteria used: The
criteria used to select the functional groups for analysis should be
documented. This information provides transparency and helps ensure the
analysis is based on valid and defensible criteria.
·
Analysis priority and basis for
decisions: The priority for analysing each functional group and the basis for
those decisions should also be documented; this includes the rationale for why
certain functional groups were deemed a higher priority and the factors
considered in making those decisions.
·
The operating context for each selected
functional group: Finally, the operating context for each selected functional
group should be documented; this includes factors such as operating
environment, duty cycle, and maintenance history, which can influence the risk
of equipment failure.
2.7.1.2
IDENTIFYING FUNCTIONS AND FUNCTIONAL FAILURES
To
ensure comprehensive documentation of functions and functional failures in the
RCM analysis, the following must be documented:
·
Primary functions: These are the
functions that are essential for the vessel's operation and should be
identified and documented. This includes a description of the function, a verb
(action), an object (what is being acted upon), and a performance standard (the
level of performance required).
·
Secondary functions, including all
protective functions, support the primary functions or protect against failure.
They should also be identified and documented in the same manner as primary
functions.
·
Functional failures related to primary
and secondary functions: Each functional failure must be associated with the
relevant function and documented in the same format as the functions; this
includes a description of the failure, a verb (what is not being done as
required), an object (what is affected by the failure), and a performance
standard (the level of performance that is not being achieved).
Functions
and functional failures can be documented in either a functional block diagram
or in a tabular format. Whichever format is used, it is essential to ensure
that each function and failure statement includes the necessary elements to
provide a complete understanding of the vessel's functions and the potential
failures that may occur.
2.7.1.3
CONDUCTING AN FMECA
The
documentation for the Failure Modes, Effects, and Criticality Analysis (FMECA)
step includes the following:
·
A description of how the FMECA was
conducted: This describes the methodology and process used to conduct the
FMECA. This information can help ensure that the analysis is consistent and
reproducible.
·
A description of the risk-based decision
tools used to assess criticality: This describes the decision tools used to evaluate
the criticality of equipment failures. This information provides context for
understanding how the criticality ratings were determined.
·
The FMECA worksheets: The FMECA
worksheets document the analysis results, including the identified failure
modes, their causes, the functional failures, and the end effects resulting
from those failures.
The
risk-based decision tools used in the FMECA are typically documented in a
tabular format that includes:
·
A description of consequence categories:
This outlines the potential consequences of failure, such as
safety, environmental impact, or operational downtime.
·
A description of probability categories
outlines the likelihood of a failure occurring, typically on a scale from low
to high.
·
The risk matrix with risk levels
identified: The risk matrix visually represents the criticality
rating for each failure mode based on its consequence and probability. This
allows for a quick and easy assessment of the risks associated with each
failure.
The
FMECA itself is documented in a tabular format that includes the following
information:
·
The equipment failure mode/cause: This
describes the specific equipment failure mode and its cause.
·
Functional failure: This describes the
failure resulting from the equipment failure mode.
·
The end effect resulting from the
functional failure outlines the potential consequences of the functional
failure.
The
criticality associated with the failure mode and resulting functional failure:
This rates the criticality of the failure mode and resulting functional failure
based on the identified consequence and probability categories.
2.7.1.4 SELECTING A FAILURE MANAGEMENT STRATEGY
The
documentation for the task selection and implementation step in the RCM
analysis should include the following:
·
The RCM decision diagram: This provides a
graphical representation of the decision-making process used to select
maintenance tasks or one-time changes based on the results of the FMECA. The
decision diagram should identify when a one-time change is required or should
be considered, the types and order of maintenance tasks to be considered, and
when run-to-failure is an acceptable failure management strategy.
·
The task selection worksheets document
the specific maintenance tasks or one-time changes proposed based on the
decision diagram. The worksheets should be documented in a tabular format that
includes relevant equipment failure mode/cause and criticality information from
the FMECA, the decision point in the RCM decision diagram that is the basis for
the proposed task or one-time change, the proposed tasks and their associated
interval, and an evaluation of the risk reduction anticipated from implementing
the proposed task and/or change.
·
A description of the RCM analysis process
outlines the methodology and process used to conduct the RCM analysis. This
information can help ensure that the analysis is consistent and reproducible.
·
The composition of the analysis team:
This describes the individuals involved in the RCM analysis, their roles and
responsibilities, and their qualifications.
·
Any analysis assumptions or exclusions:
This outlines any assumptions or exclusions made during the analysis that may
have influenced the results.
2.7.2 RCM PROGRAM SUSTAINABILITY
A
maintenance program based on the RCM philosophy is not a static document but
rather a dynamic one that requires continual refinement and updating throughout
the vessel's operating life. Therefore, the vessel operator must be
prepared to collect, analyse, review, and respond to in-service data
continually to ensure the program remains effective; this information is used
to refine the maintenance program through RCM analysis and update the program
plan's procedures and processes.
The
decisions made during an RCM analysis are also not static. The maintenance
program must be continuously reviewed and refined as it undergoes changes due
to equipment modifications and modernisation. Therefore, an organised
information system is necessary to capture data from maintenance tasks'
performance and other analyses, such as periodic root cause failure analyses.
This information determines what refinements and modifications need to be made
to the initial maintenance program and the need for other actions, such as
product improvement or operational changes.
Monitoring
and adjusting existing maintenance tasks, developing emergent requirements, and
periodically assessing RCM-generated maintenance requirements meet these two
purposes. In addition, analysts use this new information to revise RCM
analyses, which may reflect the need for changes to the maintenance program.
By
continually monitoring and adjusting the maintenance program through RCM
analysis and using an organised information system to capture relevant data,
organisations can ensure that their maintenance program remains effective
throughout the vessel's operating life. This documentation can also aid in
communication and understanding between stakeholders involved in the analysis.
2.7.2.1 SUSTAINING
THE ANALYSIS
The
following RCM sustainment processes can be applied to achieve the objective of
the sustainment process in RCM analysis:
·
Performance monitoring: This involves
monitoring the performance of the maintenance program and identifying areas
where the program can be optimised or improved.
·
Failure trend analysis involves analysing
failure data to identify any adverse trends and taking corrective action to
address them.
·
Review of new equipment and system
changes: This involves reviewing them to ensure they are incorporated into the
maintenance program.
·
Maintenance program optimisation involves
identifying and eliminating unnecessary requirements from the maintenance
program to improve overall efficiency.
·
Root cause failure analysis involves
conducting root cause failure analysis to identify the underlying causes of
failures and taking corrective action to prevent similar failures.
·
Review of new technology: This involves
reviewing new technology to determine whether it can be incorporated into the
maintenance program to improve overall effectiveness.
The
results of the sustainment process can effectively support RCM
analysis updates and ensure that the maintenance program remains effective
throughout the vessel's working life.
2.7.2.1.1 TREND ANALYSIS
A trend
analysis is a valuable tool for identifying systems or components that may be
degrading. The measurement factors used for trending may be condition-monitoring parameters (e.g., temperatures, pressures, and power) or the
results of chronic root-cause failure analyses.
When
performing trend analyses, the change in value, rather than the values
themselves, is essential. Statistical measures such as mean and standard
deviations can establish performance baselines and compare current performance
levels to established control levels. Performance parameters can then be
monitored, and causes can be investigated for those parameters that exceed
control limits.
After
the problem has been characterised, the related RCM analysis should be reviewed
and updated as necessary. Other corrective actions should also be considered
and implemented to reduce the causes of performance deviations.
The
trend analysis results can also provide valuable information for ongoing
maintenance program optimisation. For example, suppose the trend analysis identifies a particular system or component consistently performing below the established control level. In that case, the maintenance program can be adjusted accordingly, including
more frequent inspections or extensive repairs to the affected system or
component.
To ensure an effective maintenance program, trend analysis for repeat equipment failures and a comparison of machinery reliability before and after implementing the RCM-derived maintenance tasks are essential.
Repeat
equipment failures can indicate underlying systemic issues that the initial RCM
analysis may not have adequately addressed. Organisations can identify and address repeat equipment failures by tracking and analysing them to optimise their maintenance program.
Comparing
machinery reliability before and after implementation of the RCM-derived
maintenance tasks provides valuable insights into the effectiveness of the
maintenance program. Metrics such as mean time between failures (MTBF) and mean
time to repair (MTTR) can be tracked to assess the impact of the RCM-derived
maintenance tasks on machinery reliability and identify areas for improvement.
Establishing
trend analysis for these factors involves setting baselines and tracking
changes over time using statistical measures to identify significant changes in
performance. The trend analysis results can then be used to update the RCM
analysis and optimise the maintenance program accordingly.
2.7.2.1.2 MAINTENANCE REQUIREMENTS DOCUMENT REVIEWS
Documents
containing maintenance requirements should be periodically reviewed to identify
outdated processes, techniques, or technologies, as well as obsolete tools and
supplies, to ensure the effectiveness and efficiency of the maintenance
program. These document reviews provide opportunities to update maintenance
requirements and improve their effectiveness or reduce life-cycle costs.
In
addition, service bulletins from equipment manufacturers should be regularly
reviewed and evaluated for their impact on the RCM program. These bulletins can
provide valuable information, such as new condition-monitoring techniques and
updated life limits for components.
2.7.2.1.3 TASK PACKAGING REVIEWS
Task
packaging is an essential process in the maintenance program. It involves
incorporating several RCM-derived maintenance tasks into optimum uniform
intervals, such as during a vessel's scheduled dry-docking.
Maintenance tasks remain in the same packaged intervals as they are modified
and updated.
However,
the initially packaged interval may no longer be optimal over time. Therefore, periodic task packaging reviews are essential to evaluate the packaged maintenance intervals and ensure that optimum intervals are maintained, even as maintenance tasks are added, deleted, or modified.
Organisations
can ensure their maintenance program remains effective and efficient by
conducting periodic task packaging reviews. This documentation can also aid in
communication and understanding between stakeholders involved in the analysis.
In addition, task packaging reviews provide an opportunity to evaluate the
maintenance program and identify areas where improvements can be made to
optimise the maintenance intervals and reduce life-cycle costs.
2.7.2.1.4 AGE EXPLORATION TASKS
In
cases where insufficient age-to-failure data or assumed data are used during
the initial RCM analysis, age exploration tasks may be designed and
implemented. However, an effective RCM program will require frequent changes to
the age exploration program, such as adding new equipment, deleting completed
or unproductive tasks, or adjusting task intervals.
Age exploration tasks result in a better understanding of the system or
equipment's wear-out region of the failure characteristics curve. This
information can be used to update the RCM analysis, thereby improving the
accuracy of the maintenance program. In addition, the RCM analysis should guide
the implementation of age exploration tasks.
By
conducting age exploration tasks, organisations can gain valuable insights into
the wear-out region of the failure characteristics curve and identify areas
where maintenance tasks can be optimised to improve the overall effectiveness
and efficiency of the maintenance program. This documentation can also aid in
communication and understanding between stakeholders involved in the analysis.
Regularly reviewing and updating the age exploration program as needed ensures
that the maintenance program remains effective and efficient throughout the
vessel's operating life.
2.7.2.1.5 FAILURES
An
effective RCM program should have a process for addressing failures (loss events) and other unpredictable events and determining the appropriate response or corrective action. This process is essential to ensuring the safety and reliability of vessels and optimising the maintenance program.
A root
cause analysis should be the first step taken to develop an understanding of
the failure or loss event. This analysis uses a structured process to identify
areas that require further analysis, such as maintenance, operations, design,
and human factors. The key steps in a root cause failure analysis include:
•
Identifying the failure or potential
failure
•
Convening a trained team suitable for
addressing the issues posed by the event
•
Gathering data to understand how the
event happened
•
Performing a root cause failure analysis
to understand why it happened
•
Generating corrective actions to prevent
it and similar events from recurring
•
Verifying that corrective actions are
implemented
•
Putting all of the data related to the
event into an information system for trending purposes
By
following these steps, organisations can address failures and other
unpredictable events in a timely and effective manner; this helps to ensure
that their vessels remain safe and reliable and that their maintenance program
remains optimised.
When a
failure or other unpredicted event occurs, the results of reviewing the RCM
analysis should be considered when determining a response. An RCM review should
be part of the overall methodology to determine if changes in maintenance
requirements are necessary. This review can indirectly aid in deciding if
corrective actions are required. Any decisions not to update the RCM analysis
should be documented for audit purposes.
During
the RCM review, several questions should be addressed, such as whether the
failure mode is already covered, whether the failure consequences are correct,
whether the reliability data are accurate, whether the existing task is
adequate, and whether the related costs are accurate. If new or previously
unlikely failure modes are significant, the RCM analysis should be updated.
Existing analyses for failure modes may also be inadequate for various reasons,
such as changes to mission requirements or operator and maintenance procedures.
Failures
and other unpredicted events can be identified through several sources, such as
defect reports issued by maintenance engineering or the vessel's crew, defects
discovered during routine vessel repairs in a shipyard, vendor and original
equipment manufacturer reports related to inspections, rework, or overhauls,
design changes, and test results. If any of these events require RCM review
and update, it should be done promptly to ensure that the maintenance program
remains effective and reliable.
2.7.2.1.6 RELATIVE RANKING ANALYSIS
To
effectively prioritise maintenance tasks, it is crucial to rank equipment or
systems based on their impact. Various measurement factors can be used to
develop this ranking, including maintenance man-hours, maintenance man-hours
per operating hour, equipment downtime, maintenance actions per operating hour,
cost of lost production, and cost of repair.
Identifying
the highest contributors requires detailed data analysis and communication with
operators and maintainers. It is important to note that this analysis only
identifies the worst-performing items, not those in the degradation process.
Some items may naturally appear at the top of the list due to their nature and
use.
Further
RCM analyses may benefit these top-performing items, and other analysis
techniques, such as root cause analysis, may need to be employed to improve
their performance. A comprehensive approach to prioritising maintenance tasks
can help ensure that limited resources are allocated to the most critical
equipment or systems, optimising maintenance efforts and minimising the risk of
equipment failures.
2.7.2.1.7 OTHER ACTIVITIES
Internal
audits by the operator can lead to changes in the RCM analysis and/or
preventative maintenance tasks. In addition, these audits may identify areas
for improvement in the maintenance program, including potential gaps or
inconsistencies in the RCM analysis.
Based
on the internal audit findings, the operator may need to update the RCM
analysis to reflect any changes in equipment or operating conditions, revise
maintenance tasks or intervals to address identified gaps or inefficiencies or
implement new processes or procedures to improve the effectiveness of the
maintenance program.
Operators
need to prioritise continuous improvement efforts through regular internal
audits and reviews of the maintenance program to ensure that the RCM analysis
and preventative maintenance tasks remain practical and up-to-date.
2.7.2.2 RESULTS OF
SUSTAINING EFFORTS
Sustaining
efforts can also change the RCM analysis or existing maintenance tasks. These
changes may include:
·
Refining maintenance task intervals:
Through the collection and analysis of data during sustaining efforts, it may
be determined that an existing maintenance task is not being performed at its
most effective interval. This data can refine the assumptions used to establish
the interval during the initial RCM analysis and improve the task interval's
effectiveness.
·
Adding, deleting, or modifying
maintenance tasks: Sustaining efforts may also identify maintenance tasks that
need to be added, deleted, or modified to improve the effectiveness of the
maintenance program.
·
Modifying age exploration tasks:
Sustaining efforts may require modifying age exploration tasks to improve their
effectiveness.
·
System or equipment redesign: Due to
sustained efforts, it may be determined that a system or equipment redesign is
necessary to improve performance or reduce maintenance requirements.
·
Operational changes or restrictions:
Sustaining efforts may also identify the need for operational changes or
restrictions to reduce the likelihood of failures or improve overall system
performance.
2.7.2.3 RCM PROGRAM
EFFECTIVENESS ASSESSMENT
Operational
availability measures the percentage of time that the equipment is available
for its intended purpose and can be used to assess the effectiveness of the RCM
program. The program's effectiveness can be evaluated by comparing the
operational availability before and after the implementation of the
RCM-generated maintenance tasks. In addition, the mean time between failures
(MTBF) and the mean time to repair (MTTR) can also be used to assess the
program's effectiveness in reducing equipment failures and improving repair
times.
Overall,
a successful RCM program should show decreased maintenance costs, increased
operational availability, and reduced frequency and severity of equipment
failures. These metrics should be regularly monitored and reported to
management to demonstrate the program's effectiveness and identify improvement
areas."
Measuring
the availability of equipment or systems before and after implementing an RCM
program can indicate the effectiveness of RCM-generated tasks. For example,
without an RCM program, some equipment may require extensive unscheduled
maintenance, negatively impacting availability. Conversely, equipment subject
to too much maintenance can also affect availability.
In
addition to measuring availability, several other relevant maintenance metrics
can be used to monitor the effectiveness of the RCM program. These metrics
include compliance with the RCM maintenance plan, safety performance metrics
such as the number of recordable incidents or incident rate, environmental
performance metrics such as permit exceedances or average emission rates,
miles/ton of fuel, asset downtime, number of breakdowns, port maintenance days,
and a comparison of actual maintenance costs to budgeted maintenance costs.
2.7.3 RCM & PREVENTATIVE MAINTENANCE PLANS – EXISTING VESSEL
APPLICATION
RCM
analyses can be performed on existing machinery systems where the vessel's
owners and operators have significant operating and maintenance experience.
While the current proactive/preventative maintenance plan may be satisfactory,
it may be excessive or fail to address specific equipment failure modes. RCM
analysis can verify the existing plan's effectiveness, identify previously
unaddressed failure modes, and identify unnecessary maintenance activities.
Various
methods are available to streamline RCM analyses and reduce the time and effort
required. However, any analysis must address all the system's failure modes.
Failure to do so may result in an inadequate preventative maintenance plan,
which could lead to preventable consequences. Therefore, it is important to
ensure that any RCM analysis considers all potential failure modes.
2.7.3.1 SYSTEM
TEMPLATES
Many
marine systems and equipment installed on various vessels share similarities in
their arrangement and purpose. To assist Owners/Operators, we have created
several templates for piping systems and equipment. These templates are
partially completed Failure Modes and Effects Analyses and include a high-level
system schematic, a detailed system schematic, a list of system functions, and
suggested functional failures. They also provide a failure modes and effects
analysis, including system equipment item/components, suggested failure modes,
possible causes, local effects, functional failures, end effects, and failure
detection and corrective measures (indications and safeguards). While these
templates can reduce the time needed for a thorough analysis and provide
consistent analysis to Owners/Operators, individual vessel classes may have
unique features or failure modes not included in these templates. Therefore, the
Owner/Operator is responsible for verifying and revising these templates to represent
the systems onboard accurately.
References
& Bibliography:
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Novitasari, D., Lienard, C. and Wijaya, D., 2021. The Combination of Reliability and Predictive Tools to Determine Ship Engine Performance Based on Condition Monitoring. Available at: https://www.researchgate.net/publication/350303270_The_Combination_of_Reliability_and_Predictive_Tools_to_Determine_Ship_Engine_Performance_based_on_Condition_Monitoring [Accessed 2 July 2022].
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Kassapi, M. and Charalambous, G., 2009. Increasing Ship Operational Reliability Through the Implementation of a Holistic Maintenance Management Strategy. Available at: https://www.academia.edu/962903/Increasing_ship_operational_reliability_through_the_implementation_of_a_holistic_maintenance_management_strategy [Accessed 2 July 2022].
American Bureau of Shipping, 2018. Reliability-Centered Maintenance. Available at: https://ww2.eagle.org/content/dam/eagle/rules-and-guides/current/design_and_analysis/132_reliabilitycenteredmaintenance/rcm-gn-aug18.pdf [Accessed 2 July 2022].
Disclaimer:
Out of Box Maritime Thinker © by Narenta Consilium Group 2022 and Aleksandar Pudar assumes no responsibility or
liability for any errors or omissions in the content of this paper. The
information in this paper is provided on an "as is" basis with no
guarantees of completeness, accuracy, usefulness, or timeliness or of the
results obtained from using this information. The ideas and strategies should
never be used without first assessing your company's situation or system or
consulting a consultancy professional. The content of this paper is intended to
be used and must be used for informational purposes only.
