Many, many moons ago I was tasked with coming up with a defining document for a Proactive Maintenance Program that a client company was in the course of implementing. This was part of a Total Productive Maintenance (TPM), Lean management effort. This was to be a Level III Document with all lower tier documents providing supporting process and procedure to that client’s maintenance (as a business) goals. Over the years I have modified the document, leaving the basic premise of defining specific acceptance criterion for all work. To me, defining specific acceptance criterion for work performed is key to any Reliability Centered Preventive and Condition Based Maintenance process, e.g. to ensure work is accomplished ‘error-free’ and defects are identified prior to functional failure, a compliance based process is necessary. The following is the latest iteration of that document. Hopefully it will help you define a process representing your company’s goals as they pertain to The Business of Maintenance.
Overall
This document outlines the Proactive Maintenance strategy that will be utilized on an owner’s identified business critical assets. The primary goal of this Proactive Maintenance process is to eliminate the introduction of error(s) during operation and maintenance of identified critical assets. As a secondary goal, inspection technologies and techniques will be applied to assets in a dynamic state that identify defects early enough to allow repairs prior to critical assets experiencing functional failure(s). Because this process is applied to critical assets, Run-to-Failure strategies will not be addressed in this document or any supporting documents. Primary and secondary goals will be met by incorporating elements of classic Preventive Maintenance (PM) (time based maintenance) and Condition Based Maintenance (CBM) actions into an effective work management process. If the PM and CBM activities are managed competently, utilizing recognized industry best-practices, results can be measured as World-Class.
Elements of this process may, and in most cases should, be used when developing maintenance strategies for less critical assets. The owners and stakeholders should evaluate systems, equipment and components, case by case, to determine if it is economically beneficial to include less critical assets.
Proactive Maintenance Strategy
An effective Proactive Maintenance strategy has a well-defined implementation process. The implementation process is documented, is communicated and is understood by all asset owners and stakeholders. This is accomplished through initial and ongoing training at all levels, from executive management to field level personnel. Providing and communicating the implementation process is vital to effectively establishing status and understanding key performance indicators (KPI) during planning, scheduling and strategy meetings, in support of corporate wide improvement initiatives, and for sustaining a world-class program. Successful documentation and communication will also ensure commonality and consistency of process implementation throughout a fleet of similar facilities.
Motivation for a Proactive Maintenance Strategy
In line with today’s profit motivated and cost conscious corporate structures, remaining uninformed of the latest inspection technology(s) and techniques, not fully utilizing proven engineering and quality assurance principles and tools, and simply identifying and executing PM and CBM tasks and activities without basis or specific goals is unacceptable. The approach of “that’s how we’ve always done it” or “that’s what the vendor told us” will not achieve consistent and measurably improved asset availability or reliability. PM and CBM tasks and activities must be defined and executed with structure and discipline by trained and knowledgeable individuals. The consequences of not embracing structure and discipline or training that ensures technical knowledge is applied, maximizing critical asset performance, are higher costs with degraded asset availability and reliability. Decay of management structure, process discipline and technical knowledge bases are proven root causes of poor business and financial performance; e.g. increasing costs due to poor application of proactive processes. In a worse case, this leads to extreme cost cutting measures that in reality exacerbate poor critical asset performance. Asset heavy companies, such as a utility or a product manufacturer, using an undisciplined approach in developing and executing PM and CBM tasks, populated by uninformed or misinformed maintenance and operations organizations, with no regard for the cost effectiveness or impacts on reliability, will not and should not survive.
Reliability Centered Maintenance
Effective PM and CBM tasks will embrace a Reliability Centered Maintenance (RCM) based approach; an Engineered approach. Using an engineered approach, PM tasks identify and integrate failure mitigation steps into all work activities. Failure mitigation steps are designed to eliminate (or at least minimize) the introduction of error. Again, using an engineered approach, CBM tasks identify and integrate specified performance criteria into monitoring steps. These steps are designed to assess the dynamic condition of critical assets, e.g. identify faults before they cause a functional failure. These basic premises are the focus of world-class PM and CBM program(s).
However, even with the integration of PM failure mitigation and CBM performance criteria providing depth of program, to ensure appropriate stewardship of the company’s critical assets, processes must also incorporate lessons learned, continuous improvement, and root cause to ensure a value added return on the initial RCM investment. Other items that are pertinent to a successful RCM based approach are safety, environmental and Quality Assurance compliance plus corporate business goals and initiatives (The Business Case). The combined influence of these practices and principles will ensure structure and discipline in managing and maintaining an RCM based approach.
Examples of well suited and integrated tasks and activities that would become the basis of a structured and disciplined Proactive Maintenance Strategy are represented in the following table:
Preventive Maintenance
(Static, Time Based)
|
Condition Based Maintenance
(Dynamic)
|
|
|
Proactive Maintenance strategies are inherently economical once implemented. That is what makes them attractive to asset heavy companies. However, they are very expensive and time consuming to implement. This is where most implementations fail. There is no business commitment toward the implementation, just the idea that there is an economic benefit. To ensure the asset owner can justify the cost of implementation, e.g. what is the value added, there must be a mechanism to show cost benefit and return on investment. The most practical approach is to initially limit the implementation to the most business critical assets. These are the assets that most likely have existing repair and cost histories and can be used to baseline overall facility reliability and production performance. Initial justifications will be based on cost modeling showing how individual events could have been prevented and the cost of production losses, e.g. unplanned outages. However, once you have an initial implementation, one that is successful with measurable performance improvements and showing higher margins of profitability, you have a business case for deeper implementations.
Any business case justification(s) for Proactive Maintenance strategy should include the following goals:
- prevent, intervene or reduce the impact of functional failures before a failure actually occurs,
- enhance equipment reliability and availability by replacing worn or expended components prior to reaching or causing functional failure,
- manage calibration and adjustment of instrumentation and control devices ensuring they function within the desired operating band and ultimately prevent equipment and systems from operating outside of their design operating envelope,
- and to provide indication of a potential for functional failure (additional risk of failure) that could lead to catastrophic loss of equipment, facility operating outside of regulatory limits or licenses, adversely impacting personal safety and health and loss of production.
The added value of a Proactive Maintenance strategy can be measured by improved overall performance. These measurable performance indicators include:
- reduction of critical asset down time,
- improving facility availability (uptime),
- minimizing the cost of asset repair and replacement,
- optimization of spare parts inventory,
- reducing Probability of Failure (Pf) or improved reliability,
- and, extending equipment service life.
Proactive Maintenance Strategies Incorporate Specific Acceptance Criteria
Effective PM and CBM tasks will incorporate Specific Acceptance (Inspection) Criteria based on Original Equipment Manufacturer (OEM) tolerances and Recognized National or International Consensus Standards. However, all criteria mustl be reviewed, refined and documented by the asset owner’s engineer prior to the crterias use for asset acceptance. This means that OEM and Consensus Standard criteria shall be evaluated by the asset owner to ensure any criteria fits the asset’s actual operating characteristics. For example, a limit recommended by a consensus standard at 200% of an asset’s normal operating characteristic may not provide indication of a potential failure. At 200%, chances are a failure has already occurred. A limit of 125% of the assets normal operating characteristic is more reasonable and would provide indication that there is a potential for failure.
To ensure that testing and inspections are meaningful and can provide coherent and consistent data, defined acceptance criteria will be required. The table below discusses the requirements for Subjective and Objective acceptance.
Subjective
(Judgmental, Experience Based)
|
Objective
(Measurable Units)
|
Using physical senses, determine the operational dynamic or static condition of equipment. Allowing this type of criteria assessment can ONLY be accomplished with associated training.
|
Anything that can be measured or observed with a specified unit of measure and within a specific tolerance range is considered objective criteria. Objective data analysis is the PREFERRED method of criteria assessment.
|
From design and procurement through demolition and disposal (the equipment life-cycle, cradle to grave), assets need to be inspected, lubricated, calibrated, cleaned, consumables replace and assets tested to a specified criteria, an accepted engineering basis (acceptance criteria). This promotes failure-free performance and operation within the assets designed operating envelope. All preoperational, intermediate and post maintenance inspections, calibrations, rebuild and tests must be as ‘objective’ as possible.
If ‘subjective’ criteria are used, it must be defined, documented and training provided to ensure commonality and consistency of application, personal and professional judgments need to be left at the change-room.
A Proactive Maintenance strategy is a winning strategy and can economically provide improved availability and reliability. You just need to understand that there are up-front costs that need to be budgeted and managed to get your best Return On Investment.
Maintenance, what a Concept!!!!
MMJennings
No comments:
Post a Comment