Glossary of Maintenance Terms

Absolute Losses
Production deferred or lost due to the specified element or system, as a percentage of the total potential production.

Acoustic Emission Analysis
Like vibration analysis, patterns of acoustic emission spectra are monitored and diagnosed. Acoustic emission analysis technology is applied to study bearing faults, detect flaws and cracks in welding and pipe-work, and to study de-lamination, de-bonding, and fracture in aerospace materials.

Activity-Based Costing (ABC)
A system that tracks costs based on the activities that are responsible for driving costs in the production of manufactured goods.

After Sales Service
All services proposed by the vendor or manufacturer after the purchase.

Agile Manufacturing
Tools, techniques, and initiatives that enable a plant or company to thrive under conditions of unpredictable change. Agile manufacturing not only enables a plant to achieve rapid response to customer needs, but also includes the ability to quickly reconfigure operations-and strategic alliances-to respond rapidly to unforeseen shifts in the marketplace. In some instances, it also incorporates "mass customization" concepts to satisfy unique customer requirements. And, in the broadest sense, it includes the ability to react quickly to technical or environmental surprises.

Alignment (Precision)
Refers to bringing or placing machine(s) shaft(s) in line. Misaligned shafts often cause problems with machine components (i.e. bearings). Specialized tools and personnel for precision alignment exist. A number of tools are based on laser technologies.

Alliance (Contract)
An alliance is a long term commitment between two or more entities for the purpose of achieving clearly stated business objectives by maximizing the effectiveness of each participant’s skills and resources, leading to an "alliance contract".

Analysis
(1) A step-by-step process of determining the solution to a problem. (2) The collection, viewing, and examination of data and information. (3) The process of determining the composition of a substance or material using chemical or physical methods.

Annual Inventory Turns
A measure of asset management that is calculated by dividing the value of annual plant shipments at plant cost (for the most recent full year) by the average total inventory value at plant cost. Total inventory includes raw materials, work in process, and finished goods. Plant cost includes material, labor, and plant overhead.

Anomaly
Something irregular or inconsistent.

Assessment / Audit
A process that attempts to quantify the actual status of a customer’s maintenance system to identify opportunities for improvement.

Asset
An entity with monetary value. In maintenance context, an asset is commonly considered to be any component of a plant or its equipment. For example, compressors, gearboxes, etc. A motor is also an asset as it is a component of a larger manufacturing unit.

Asset Efficiency Optimization (AEO^®)
A key aspect of any world-class asset management program is a proactive, efficient work management process, designed to ensure the effective performance of maintenance on critical assets. To achieve maximum return on investment and maintain the greatest degree of productivity, it is pivotal that organizations have a process that effectively translates asset information to knowledge, and ultimately releases value from that knowledge. To help organizations achieve these goals, SKF offers Asset Efficiency Optimization (AEO), a management process designed to achieve maximum efficiency and effectiveness from work management activities focused on business goals for the facility.
The AEO process encompasses four key elements: Strategy, Identification, Control and Execution. Within each of these elements, the coordination and participation of three essential facets within the organization — process, culture, and technology — is paramount to the overall impact of AEO.

Asset Knowledge Science (AKS)
An SKF process of documenting asset knowledge relevant to monitoring and diagnosing asset anomalies. The process encompasses generic literature, OEM and SKF information, and asset unique details. The goal is to provide a structure to justify which measurements are needed to detect and diagnose failures in an early stadium. The AKS is used to tune an SKF decision-support system called @ptitude^TM.

Figure: Asset Knowledge Science hierarchy.

Asset Management
The organization of an asset’s life cycle to achieve the lowest life cycle cost with the maximum availability, performance efficiency, and highest quality (maximum OEE). In other words, asset management is the systematic process of planning and control of a physical asset throughout its life. This may include the specification, design, and construction of the asset, its operation, maintenance and modification, and its disposal. Asset management provides a strong focus on technical aspects of a facts-based, proactive management attitude with a mission, vision, and objectives derived from that of the company. (U.K. Institute of Asset Management)

Asset Integrity
Asset integrity is the fitness of an asset to be operated as intended, and to perform as intended, with an acceptable risk of failure over its service life.

Asset Register
In maintenance this term usually refers to a formal, structured listing of the plant and machinery at a given location.

Asset Utilization
Percentage of time a plant or equipment is operating at maximum demonstrated production rate, with perfect quality and defined yield.

Assignment Clause
A source of variation in a process that can be isolated, especially when its significantly larger magnitude or different origin readily distinguishes it from random cause of variation. Synonym - special cause.

Availability
Availability is the probability that a system or component is performing its required function at a given point in time, or over a stated period of time when operated and maintained in a prescribed manner. In other words, the proportion of total time that an item of equipment is capable of performing its specified functions. The general observation of availability is:

By taking different measures for uptime and downtime, different availability measures are obtained.

Availability (Inherent)
Inherent availability is defined as MTBF / (MTBF + MTTR). Availability increases by increasing reliability (MTBF) and maintainability (1/ MTTR). For example: MTBF = 1000 hours, MTTR = 48 hours. Then the availability is 1000 / 1048 = 95%. The inherent availability is solely based on the failure distribution and repair-time distribution, assuming no supply and maintenance delays, and no planned (preventive / corrective) maintenance. It is considered as an equipment design parameter. Inherent availability fulfills the need to distinguish expected performance between planned shutdowns.

Availability (Achieved)
In the definition of achieved availability, the mean time between maintenance (MTBM) is used as measure of uptime. This mean time between maintenance includes both unplanned and planned maintenance. The mean (expected) system downtime includes unplanned and planned (preventive/predictive) maintenance, but does not include supply or maintenance resources delays. Achieved (equipment) availability fulfills the need to distinguish availability when planned maintenance shutdowns are included, whereby it assumes zero supply and maintenance resources delay times.

Availability (Operational)
Similar to achieved availability, but in the operational availability also the supply and maintenance resource delays are included in the mean system downtime. Operational availability is required to isolate the total effectiveness and efficiency of maintenance operations.
Remark: the mean time between maintenance and the mean system downtime can be measured in both "clock" or "calendar" time. Clock time is scheduled operating time, or "manned hours". When measuring in calendar time, the term generalized operational availability is sometimes used.
Remark: by definition, inherent availability is higher or equal to achieved availability, and achieved availability is higher or equal to operational availability.

Available Hours
The total number of hours that a piece of equipment is capable of performing its specified functions. It is equal to the total hours in any given period minus all the downtime hours.

Average Life
How long, on average, a component lasts before it suffers a failure. Average life is commonly measured by Mean Time Between Failures (MTBF), and is usually expressed in hours.
Regarding rolling element bearings and grease lubrication, the average life is calculated according general formulas (please refer to the SKF General Catalogue).

Autonomous Maintenance
Operators in independent groups carry out routine maintenance and preventive maintenance. These groups, which may include maintenance workers, solve problems without management intervention. The maintenance department is only called on for bigger problems that require more resources, technology, or downtime.

Backlog
Work that is not completed by the nominated "required by date." The period each work order is overdue is defined as the difference between the current date and the "required by date." All work that doesn’t have a specified required by date is generally included on the backlog. Backlog is often measured in crew-weeks, the total number of labor hours represented by the work on the backlog, divided by the number of labor hours available in an average week. As such, backlog is one of the common key performance indicators in maintenance.

Balanced Scorecard
A "top–down" method of translating an organization's mission and strategy into tangible linkages, interrelationships, specific activities, and measures necessary for success. Reliability and maintenance issues are integrated into an overall business scorecard or identified in a stand-alone scorecard.
See http://www.balancedscorecard.org/.

Band-Aid
A known temporary fix to a problem that may have to be performed one or more times until a permanent fix can be performed. ( A permanent fix may consist of scheduled down time requirements, re-engineering, new procedural developments, etc.)

Baseline Measurements
A set of measurements (or metrics) that seeks to establish the current or starting level of performance of a process, function, product, firm, etc. Baseline measurements are usually established before implementing improvement activities and programs.

BASEEFA
British Approvals Service for Electrical Equipment in Flammable Atmospheres. A certification body for electrical and electronic equipment for use in hazardous areas. In 1987 it was brought together with the Mining Equipment Certification Service to form the Electrical Equipment Certification Service (EECS).

BDM
See Breakdown Maintenance.

Benchmarking (Competitive)
The process of consistently researching new ideas, methods, practices, and processes, and adapting, adopting, and implementing their best features. It is the continuous procedure of measuring one’s products, services, and practices against competitive "best in class" companies or organizations for the purpose of seeking improvement.
See Key Performance Indicators.

Benchmarking (External)
The process of consistently researching new ideas, methods, practices, and processes, and adapting, adopting, and implementing their best features. It is the continuous procedure of measuring one’s products, services, and practices against external companies or organizations for the purpose of seeking improvement.
See Key Performance Indicators.

Benchmarking (Generic)
The process of consistently researching new ideas, methods, practices, and processes, and adapting, adopting, and implementing their best features. It is the continuous procedure of measuring one’s products, services, and practices against companies or organizations that carry out the same or similar functions (e.g. warehousing) for the purpose of seeking improvement.
See Key Performance Indicators.

Benchmarking (Internal)
The process of consistently researching new ideas, methods, practices, and processes, and adapting, adopting, and implementing their best features. It is the continuous procedure of measuring one’s products, services, and practices within the company for the purpose of seeking improvement.
See Key Performance Indicators.

Break Down Maintenance (BDM)
"Unplanned" corrective maintenance performed on equipment after the equipment has suffered a failure and has to be corrected during a break down of the equipment. Break down maintenance indicates a lack of planning.
See also RunTo Failure

BOI
Business Operation Income (after taxes).

Bottleneck
Any point at which production is slowed because demand placed on a resource is equal to or more than capacity. Bottlenecks identify machines that are critical to large sections of the production cycle.

Business Process Reengineering (BPR)
Business Process Reengineering or Business Process Reorganization is itself a process that aims improving organizational performance by improving its business processes. BPR came into use after Michael Hammer and James Champy published their best-selling "Re-engineering the Corporation" in 1993. Re-engineering means 'starting over' and the defining words are fundamental, radical, dramatic and process. In short, starting with a clean piece of paper, to design an organization to perform a process. Re-engineering is not about "continuous improvement", which by definition is an examination and analysis of the status quo where minute improvements are continuously applied to the existing process. A combined approach of continuous improvement and radical change (where needed) is aimed in Business Process Management (BPM).

Calendar-Based Maintenance
A maintenance strategy where specified activities (typically preventative in nature) are undertaken on a predetermined schedule at fixed intervals of time.

Call Back
A job where the maintenance person is called back because the asset broke down again or the job was not properly finished the first time.
See Rework.

Capital Spares
Usually large, expensive, long lead time parts that are capitalized (not expensed) on the books and depreciated. They are often deemed as a "protection" against downtime.

CAV
Current Asset Value.
See Estimated Replacement Value (ERV).

CBM
See Condition Based Maintenance.

Cellular Manufacturing

A manufacturing approach in which equipment and workstations are arranged to facilitate small-lot, continuous-flow production-often in a U-shaped cell. In a manufacturing "cell," all operations necessary to produce a component or subassembly are performed in close proximity, thus allowing for quick feedback between operators when quality problems and other issues arise. Workers in a manufacturing cell are typically cross-trained and, hence, able to perform multiple tasks as needed.

CEN
Comité European de Normalisation.
European Committee for Standardization.

CENELEC
CENELEC is the European Committee for Electro-technical Standardization. It was established in 1973 as a non-profit organization under Belgian Law. The European Commission in Directive 83/189/EEC has officially recognized CENELEC as the European Standards Organization.

Channel
Term used within SKF to indicate an integrated or linked production line from turning operation to packing.

Characteristic Life
The life at which 63.2% of the population has failed.
In the rolling elements bearing industry, L1 and L10 life are generally used corresponding to the number of hours at which 1% and 10% of the population has failed, respectively.
See Patterns of Failure.

Charge Rate
This is the rate that you charge for a mechanic or engineer's time. In addition to the direct wages, it includes provision for benefits and overhead (such as supervision, clerical support, shop tools, truck expenses, and supplies).

Client Needs Analysis (CNA)
The Client Needs Analysis is a quick, SKF facilitated assessment with focus on the SKF AEO solution. The Client Needs Analysis can be completed in just a few hours and asks 10 assessment questions for each of the four main facets of the AEO Process: maintenance strategy, work identification, work control, and work execution. These 40 questions are designed to investigate, quantify, and visualize the situation at the your facility. Results are displayed in a graphical “spider chart” format which provides a visual footprint of a particular plant assessment in accordance with international standards/models of business excellence.

Collinear
When the rotational centers of two shafts form a single, straight line then the shafts are said to be collinear.

Compliance Test
Test used to show whether or not a characteristic or a property of an asset complies with state requirements.

Component
A system or subsystem piece that has the ability to perform a defined function, and is physically replaceable.

Computer-Aided Design (CAD)
Computer-based systems for product design that may incorporate analytical and "what if" capabilities to optimize product designs. Many CAD systems capture geometric and other product characteristics for engineering-data-management systems, production and cost analysis, and performance analysis. In many cases, CAD-generated data is used to generate tooling instructions for computer-numerical-control (CNC) systems.

Computer-Integrated Manufacturing (CIM)
A variety of approaches in which computer systems communicate or "inter-operate" over a network. Typically, CIM systems link management functions with engineering, manufacturing, and support operations. In the factory, CIM systems may control the sequencing of production operations, control operation of automated equipment and conveyor systems, transmit manufacturing instructions to equipment or operators, capture data at various stages of the manufacturing or assembly process, facilitate tracking and analysis of test results and operating parameters, or a combination of the above.

Computerized Maintenance Management System (CMMS)
Hardware and software system used to track work orders, equipment histories, and preventive / predictive maintenance schedules; usually integrated with support systems such as inventory control, purchasing, accounting, and manufacturing; computerized system, to track, monitor, measure and control maintenance and warehouse activities. (McKenna T & Oliverson R, "Glossary of Reliability and Maintenance Terms", Gulf Publishing Company, ISBN 0-88415-360-6 (1997))

Computerized Process Simulation
Use of computer simulation to facilitate sequencing of production operations, analysis of production flows, and layout of manufacturing facilities.

Condition Based Depreciation (CBD)
A form of depreciation that directly assesses and measures the run down in service potential of an asset. It is based on an auditable and cost-justified asset renewal plan. The cost of replacing lost service potential over the next 10-30 years (the exact period depends on the agency and the nature of the assets involved) is expressed as an annuity over the period. That annuity is the depreciation estimate. CBD is re-estimated on a continuous basis, based on a rolling future period. It is only used for assets which are essentially renewable rather than replaceable, i.e. infrastructure assets.

Condition Based Maintenance (CBM)
An equipment maintenance strategy based on measuring the condition of equipment to assess whether it will fail during some future period, and then taking appropriate action to avoid the consequences of that failure. The condition of equipment is monitored using a variety of objective technologies, through the use of statistical process control techniques, by monitoring equipment performance, or through the use of the human senses. The terms Condition Based Maintenance, On-Condition Maintenance, and Predictive Maintenance are often used interchangeably.

Condition Monitoring
The use of objective technologies to measure the condition of equipment. Vibration analysis, oil analysis, and thermography are examples of condition monitoring techniques.

Conditional Probability Of Failure
The probability that an item will fail during a particular age interval, assuming that it survives to enter that age.

Conformity
Fulfillment by a product, process, or service of the specified requirements.

Continuous Improvement

Reduction to maintenance input (hours, materials, management time) to provide a given level of maintenance service. Increases in the number of assets, or use of assets with fixed or decreasing inputs.

Contract Management
Contract management is a niche within the procurement profession. It ranges from administrative aspects to the excitement and challenge of major contract negotiation. Both procurement and contract management demand competence in such areas as contract law, administration, accounting, psychology, management, and planning. (From National Contract Management Association, Vienna, Virginia, USA).

Continuous Replenishment Programs
Arrangement with supplier companies in which the supplier monitors the customer's inventory and automatically replaces used materials, eliminating the need for purchase orders and related paperwork.

Control Engineering
Control engineering is the area of method and technique to automatically control industrial processes. A commonly used industry method is the PID (Proportional, Integrative and Differential) control algorithm, implemented in PLCs (Programmable Logic Controllers).

Core Damage
When a normally re-buildable component is damaged so badly that it cannot be repaired.

Corrective Maintenance
Any planned or unplanned maintenance activity required to correct a failure that has occurred or is in the process of occurring. This activity may consist of repair, restoration, or replacement of components.

Corrosion (Moisture)
Corrosion (rust) is a chemical reaction on metal surfaces. When steel is in contact with moisture, such as water or acid, oxidation takes place, and subsequently, the formation of corrosion pits and flaking occur.

Cost of Goods Sold (COGS)
Total (annual) cost of material, labor, and utilities to produce the product.

Cost of Un-Reliability (CoUR)
The cost of lost opportunity. CoUR programs study plants as links in a chain for a reliability system, and the costs incurred when the plant, or a series of plants, fail to produce the desired result. The cost can be categorized in maintainability and reliability cost.

CQI
Continual Quality Improvement.
See Kaizen Method.

Cpk
A statistical calculation of process capability based on the relationship between process variability and design specifications. A good Cpk value indicates that the process is consistently under control, i.e., within specification limits-and is also centered on the target value. A Cpk value of 1.33 is typically considered a minimum acceptable process capability; as the Cpk value approaches 2.0, the process approaches Six Sigma capability (3.4 defective units per million). The ability to achieve high Cpk values is often related to how tight the specifications are set.

Criticality
The priority rank of a failure mode, based on some assessment criteria such as operational and HSE (Health, Safety, Environment) consequences, and the likelihood of failure occurrence.

Criticality Analysis
Criticality analysis is a method for identifying product or process criticality for the purpose of prioritizing activities like design and maintenance. It is aprocess of decomposing product or process into hierarchical components, followed by study of their failure modes and effects, and (where appropriate) their causes. Criticality is the combined measure of the failure mode probability and the severity of its effects.

Cross Functional Teams
Teams of employees representing different functional disciplines and/or different process segments who tackle a specific problem or perform a specific task, frequently on an ad hoc basis.

CSA
Canadian Standards Association. CSA International is a not-profit, non-statutory, voluntary membership association engaged in standards development and certification activities. CSA standards are often incorporated into government regulation, particularly in the fields of health, safety, building construction, and the environment.

Current Asset Value (CAV)
See Estimated Replacement Value

Customer Lead-Time
The time elapsed from receipt of an order until the finished product is either shipped or delivered to the customer.

Damage
Something that reduces the value, effectiveness, or usefulness of the thing affected.

Debris Monitoring
See Oil Debris Monitoring.

Deformation (by overload)
Overloading by static or shock loads, which leads to plastic deformations (i.e. the formation of shallow depressions in steel surfaces).

Design for Reliability
A four-phase design process to build reliability into a part, component, or system. The phases are concept, design and development, full-scale development, and operational.

De-rating
Using an item in a way that applies stresses that are below the recommended stress values.

DIN
DIN (Deutsches Institut f�r Normung) is a non-governmental organization established to promote the development of standardization in Germany and related markets. Their goals are to facilitate the international exchange of goods and services, and to develop cooperation in the spheres of intellectual, scientific, technological and economic activity. Through the European standards organizations CEN and CENELEC, DIN presents the German view of European standards, which is critical to complete the single European market. Over 12,000 DIN standards cover a wide range of topics including: physical quantities and units, fasteners, water analysis, building and civil engineering (including building materials, construction contract procedures (VOB), soil testing, corrosion protection of steel structures), materials testing (testing machines, plastics, rubber, petroleum products, semiconductors), steel pipes, machine tools, twist drills, roller and ball bearings, and process engineering. DIN Handbooks (covering subjects such as mechanical engineering, fasteners, steel, steel pipes, and welding), and most DIN standards are available as English versions, or English translations. (From http://www.cssinfo.com/info/din.html)
See Do It Now Work.

Discrete manufacturing
Manufacturing a product by means other than a continuous process.�Examples of discrete manufacturing are:

Mass production � for high volume production of an item at minimum unit cost.�Increasingly this involves the use of specialized machines for some or all parts of the manufacturing process.
Batch production typically employs general-purpose machines (as opposed to the special purpose machines employed for mass production).
Individual production for items required in low volume (typically one-offs), which results in greatly increased unit costs.

Distributed Control System (DCS)
A system customized per facility/organization and designed to meet the total measurement, control and real-time information requirements of today's process plants. A single application to connect to subsystems such as maintenance (CMMS), statistical process control (SPC), and advanced control.

Do It Now (DIN) Work
"Do It Now" means non-emergency work that has to be done immediately. An example is moving furniture in the executive wing.

Downsizing
A reduction in the number of employees that occurs due to management decision, not associated with natural attrition.

Downtime
The time that an item of equipment is out of service, for example as a result of equipment failure. The time that an item of equipment is available but not utilized is generally not included in the calculation of downtime. In other words, downtime is the time that the asset is not in a condition to perform its required function. The downtime of an item includes active maintenance time and delays due to awaiting spares, labor, facilities, movement, etc. Unless otherwise stated, downtime due to failure is considered to commence at the instant the item is deemed to have failed and to persist until the equipment is again available.

EECS
The Electrical Equipment Certification Service (EECS) is based at the UK Health and Safety Laboratory's Buxton research center. It provides a range of testing and certification services primarily related to equipment and systems intended for use in potentially explosive atmospheres.
The work of EECS originated with the Safety in Mines Research Establishment in 1926, when testing of mining equipment to prevent explosions was started in Buxton. That work continues with the Mining Equipment Certification Service (MECS), a division of EECS.
With the growth of the petrochemical industry in the 1950s and 1960s, the need for standards and a certification services outside of the mining industry led to the development of the British Approvals Service for Electrical Equipment in Flammable Atmospheres (BASEEFA). In 1987, MECS and BASEEFA were brought together to form EECS.

Effectiveness
A measure of the degree to which an item, system, or person can be expected to achieve a set of specific mission requirements. Performing the correct task efficiently.

Efficiency
In a general sense, efficiency relates to competence: the ability to do something well or achieve a desired result without wasted energy or effort.
In engineering terms, efficiency is a measure of a machine's energy effectiveness: the ratio of the amount of energy used by a machine to the amount of work done. For example, the measurement of the amount of heat produced per unit of fuel burned is a measure of a heating unit's efficiency.

Electrical Current Analysis
An investigation of the electric current (spectrum) of electric motors or generators. Through this analysis, irregularities (e.g. broken rotor bars, cracked end-rings, high resistance joints) are detected. Specialized tools and personnel exist for doing these investigations.

Electronic Data Interchange (EDI)
(EDI) links-Information-system linkages, based on communication protocols and document formats, which permit inter-company computer-to-computer communications. EDI links not only speed communication, but also eliminate re-keying of information and reduces the opportunity to introduce errors. A typical EDI application might speed information exchange between a customer and supplier company for purchase orders, invoices, or other transactions. EDI communications are often facilitated through "electronic mailbox" systems on third-party value-added networks.

Emergency Work
Maintenance work that requires immediate response from the maintenance staff. Its urgency is usually associated with safety, operational, health, or environmental effects. Emergency work is often performed without a requisite work order issued in advance.

Enterprise Asset Management (EAM) Systems
Software application to support enterprise wide asset management philosophy. A computerized maintenance management system with extended functionality which typically includes timekeeping, project management, human resources issues, payroll, core financial data, etc.
"Maintenance Management systems are often referred to as Computerized Maintenance Management Systems (CMMS) or Enterprise Asset Management (EAM) systems. The difference is essentially one of scale, and there is no clear dividing line" (Campbell J D and Jardine A K S, "Maintenance Excellence, Optimizing Equipment Life-Cycle Decisions", Marcel Dekker Inc, ISBN 0-8247-0497-5 (2001)).

Enterprise Resource Planning (ERP) system
An Enterprise Resource Planning system refers to a system comprised of a single or integrated suite of applications to manage enterprise business functions, including finance, human resources, and order fulfillment.

Equipment Lifetime
Span of time over which equipment is expected to fulfill its intended purpose.

Erosion (electric)
Electric erosion is damage to contact steel surfaces caused by the passage of electric current. Small current leakage typically results in small craters, and possibly flutes or discoloration. Large craters can result from excessive voltage leaks.

ERP
See Enterprise Resource Planning System.

Estimated Plant Replacement Value (EPRV)
The ERV of a plant. A plant can represent part of, or a complete, production facility.
See Estimated Replacement Value (ERV)

Estimated Replacement Value (ERV)
The cost of capital works required to replace specific existing assets, including necessary facilities (such as buildings, energy, and other supply systems) with new assets capable of producing the same quantity and quality of output. This is a key value often used in benchmarking activities at the highest level. It is not the book value, nor the current cost accounting value, nor costs to build a state of the art replacement. ERV is an estimate of the current replacement cost (normally the insurance value).
To calculate the ERV, determine if the original equipment investment figures reasonably agree with equipment actually in use. Then identify clusters of equipment by the year in which they were acquired. Consider each cluster of investment and escalate it to a current value using a selected inflation index (e.g., the Bureau of Labor Statistics Construction Cost Index (BLS CCI)). Then the indexed clusters of investment are totaled to get the current value of plant and/or equipment. The indexed value of the plant could be compared with other plants recently built, adjusting for size and available insurance values. Even when a company is self-insured, there is normally an established "insurance value" to help define the financial exposure the company risks. An insurance underwriter typically prepares these values, even if the plant is self-insured. Underwriters follow a procedure very similar to the one described.
ERV is often used to normalize maintenance cost as a convenient basis for comparing plants of a similar type that vary in size. The rationale for using the ERV rather than the original cost of the plant is to account for construction cost escalation over time (inflation). Two relatively new plants built 10 years apart could have original costs that vary by 50 to 100 percent. Maintenance cost/ERV can be used to set long-term goals, and targets for plant reliability. World-class plants tend to fall in the range of 1 to 2.5 percent.

Event Tree Analysis (ETA)
Starting with an initiating event, event trees employ forward logic to construct a graphical representation of subsequent consequences. If successful operation of a system depends on an approximately chronological, but discrete, operation of its units or subsystems, then an event tree can be an appropriate analysis technique.

Expert System
An expert system is a software system designed for decision support. It makes or evaluates decisions based on rules, empirical test results, cases, or other knowledge sources. Expert systems are typically used for assessment and diagnosis tasks that are perceived as knowledge-intensive. The term “expert systems” originates from the 80's and was used for rule-based systems only; a better term that covers the broad range of "expert" system types is Knowledge-Based Systems (KBS).

Failure
A lack of success in something, or an unsuccessful attempt at doing something. A breakdown or decline in the performance of something, or an occasion when something stops working or stops working adequately. Note that "failure" is an event, as distinguished from "fault" which is a "state."
See Functional Failure.

Failure Cause
The apparent cause of a functional failure, not to be confused with the root cause, which is only determined through a Root Cause Failure Analysis (RCFA). (Used interchangeably with Failure Reason).

Failure Characteristics
Terms used to describe the characteristics of a failure include hidden, predictable, preventable and random.

A hidden failure singularly results in a complete loss of function without being immediately evident.
A predictable failure displays some evidence, at an early stage, of the potential for failure, and a reasonable estimate of the time interval before full functional failure occurs.�
The term "preventable" describes those failures for which there is a reliable time interval or usage (such as number of cycles) before functional failure occurs.
Random refers to a failure that occurs at any time and is not necessarily constrained by time or usage.

Failure Code
An alphanumeric code typically entered against a work order in a computerized maintenance management system (CMMS), which indicates the failure cause (e.g. lack of lubrication, metal fatigue, etc.). These codes are employed to facilitate analysis of plant history.

Failure Consequences
A term originating from reliability-centered maintenance (RCM). The consequences of all failures are classified as being either hidden, safety, environmental, operational, or non-operational.

Failure Descriptor
The term failure descriptor refers to the apparent observation of a failure. The failure descriptor must answer the question of what caused the equipment to fail to perform or fulfill the required function(s).

Failure Effect
A description of the events that transpire after a failure has occurred as a result of a specific failure mode.
See failure consequences.

Failure Finding Interval
How often a failure finding task is performed. It is determined by the frequency of failure of the protective device, and the desired availability required of that protective device.

Failure Finding Task
A routine maintenance task, normally an inspection or a testing task, designed to determine, for hidden failures, whether an item or component has failed. A failure finding task should not be confused with an on-condition task, which is intended to determine whether an item is about to fail. Failures finding tasks are used in reliability-centered maintenance (RCM), and are sometimes referred to as functional tests.

Failure Mode
The term failure mode refers to the observed way or mechanism of failure. For a failure mode to be valid it must answer the question: “What is the primary manner in which the associated failure descriptor becomes evident?” Depending on the application, the definition of failure mode may slightly vary.
In a detailed analysis, a failure mode can refer to a physical event / mechanism that gave rise to a failure (e.g., moisture corrosion, fatigue, wear). Or from a functional point of view, a valve can have several failure modes such as, "fails to operate on demand, valve leakage," etc. In a formal Reliability-centered Maintenance (RCM) program, deeper failure modes are considered as failure causes.
Failure modes may also be defined according to the effect by which a failure is observed. A high level model system may include the following general failure modes:

CRT: General critical failure resulting in 100% production loss.
DEG: Degraded equipment performance, resulting in partial production loss while waiting for repair and 100% production loss during repair.
INC: Incipient failure.� Equipment failure did not result in immediate production loss.� The failure was found during other repair / scheduled maintenance activities.� 100% production loss during repair.
UNK: No impact details are recorded in database.� 100% loss of equipment item on repair.

Failure Mode, Effects (& Criticality) Analysis (FME(C)A)
FME(C)A is a procedure that analyzes failures (failure modes) and determines their impact (effect) at both the local and system levels. The analysis can be carried out from the lowest to the highest level of the system (bottom up), which is commonly referred to as a hardware analysis. Alternatively, the analysis can be carried out from the highest level to the lowest level (top down) of the system, which is commonly referred to as a functional FMEA. The functional FMEA considers the functional failure of components within a system.
FMEA is applied in maintenance tasks, such as reliability-centered maintenance (RCM) and risk-based maintenance (RBM). The effects are generally classified as operational (production), environmental, and safety effects. This procedure is used to plan tasks to find minimum ratio between maintenance cost and cost due to failure effects. FME(C)A is a structured method to determine equipment functions, functional failures, and assess failure causes and effects.

Failure Patterns
See Patterns of Failure.

Failure Rate
Failure rate refers to the overall speed of failures, or the number of failures that occur in a given time frame, usually expressed in years. The total number of failures within an item population is divided by the total time expended by that population during a particular measurement interval under stated conditions. Failure rate is the ratio of the number of failures that occur in an interval to the size of the original population, divided by the length of the time interval. Other formats include the number of failures per year, and in some cases, it is common to express failure rate as the number of failures per hour, or the number of failures of an item per unit time. This can be applied to:

Observed failure rate: as computed from a sample
Assessed failure rate: as inferred from sample information
Extrapolated failure rate: projected to other stress levels

Failure Reason
Sometimes used to refer to the apparent root cause of a functional failure, but not to be confused with the real root cause obtained from a thorough root cause failure analysis (RCFA). Used interchangeably with Failure Cause.

False Brinneling
False brinneling occurs in rolling element bearing contact areas due to micro movements under cyclic vibrations, at times when the machine is not rotating. Depending on the intensity of the vibrations, lubrication / preservative condition, and load, a combination of corrosion and wear occurs, which forms shallow depressions in the raceways. In the case of a stationary bearing, the depressions appear at rolling element pitch and may be discolored (red) and shiny.

FAS
Shipping term meaning “Free Along Side.” This means that the price quoted for goods includes carriage to the ship, but does not include loading or subsequent carriage costs.

Fatigue (Subsurface initiated)
Under the influence of repetitive (especially high) loads in any metallic contact, structural changes occur in steel, and cracks are initiated at a certain depth under the surface, due to volume changes of the altered material. Cracks propagate through the material until they reach the surface. In extreme cases, cracks further propagate until the component completely fractures (ISO/CD 15243).

Fatigue (Surface initiated)
Surface initiated fatigue or surface distress refers to the failure of any metal surface contact due to a fatigue process started from the surface. Generally, a surface defect, such as a foreign particle indentation or a corrosion pit, is the initiator. The fatigue process is especially accelerated by a reduced lubrication regime (ISO/CD 15243).

Fault
A defect or imperfection. A fault develops when physical degradation has occurred, but the degradation is not severe enough to be termed as failure. A fault is absolute. This means there is a sufficiently high degree of confidence that a detailed physical examination of the component in question will show a fault that is absolutely supported by the symptom(s).

Fault Tree Analysis (FTA)
Fault tree analysis is a deductive process by means of which an undesirable event, called the top-event, is postulated, and the possible ways for this event to occur are systematically deduced

Feedback
When used in a maintenance context, feedback means that information from the individual failure history is accounted for in the task list. The list increases when failure history is high, and decreases when failure history is low.
In control engineer context, feedback means that measurements are taken from a process and used to take (automated) control actions (i.e., to keep a temperature constant over an operating range).

Finished-Goods Turn Rate
A measure of asset management that typically is calculated by dividing the value of total annual shipments at plant cost (for the most recent full year) by the average finished-goods inventory value. Plant cost includes material, labor, and plant overhead.

Finished-Product First-Pass Yield
The percent of finished-products that meet all quality-related specifications at a final test point. In process industries, yield is often calculated as the percentage of output that meets target-grade specifications (excluding saleable "off-grade" product).

Five-S (5-S) Concept
The “5-S Concept” was developed by the Japanese over a period of time to ensure a culture of organization within the manufacturing and service environments, which leads to higher quality. The 5 S’s, closely translate from Japanese to English as Sort, Simplify, Shine, Standardize, and Sustain.

Flow Chart
A flow chart is a diagram that uses graphic symbols to depict the nature and flow of the steps in a process. Another name for this tool is "flow diagram." A flow chart is a graphical representation of a process, depicting inputs, outputs and units of activity. It can represent the entire process at a high or detailed (depending on your use) level of observation, allowing analysis and optimization of workflow.

FMEA
Failure Mode Effect Analysis.
See Failure Mode, Effects (& Criticality) Analysis (FME(C)A).

FMECA
See Failure Mode, Effects (& Criticality) Analysis (FME(C)A).

FOB
See Free On Board.

Focused-Factory Production
A plant configuration and organization structure in which equipment and manpower is grouped to create essentially self-contained "mini-businesses," each with a specific product-line or customer focus. A single plant may be divided into several focused-factory units, designed around process flows, each of which has control over such support activities as maintenance, manufacturing engineering, purchasing, scheduling, and customer service.

Forecast/Demand Management Software
Software that provides front-end input to master production scheduling systems and helps to optimize inventory planning. Such software not only takes into account historical demand trends, but also may calculate the impact of planned sales promotions, price reductions, and other factors that cause spikes in demand levels.

Fracture (forced)
Forced fracture is caused by high stress concentration in excess of material tensile strength by local overloading (e.g. by impact).

Fracture (fatigue)
Fatigue fracture results from frequently exceeding a fatigue strength limit, often under bending condition or excessive compressive loads. Cracks are initiated at little defects and propagate stepwise through the component.

Free Along Side (FAS)
Shipping term meaning that the price quoted for goods includes carriage to the ship, but does not include loading or subsequent carriage costs.

Free On Board (City, Shipping point, or Delivered)
Free On Board (seller will load truck or rail car). "FOB delivered" keeps the vendor responsible for the shipment until it reaches your door. "FOB shipping point" or "FOB originating city" makes you responsible for the shipment. If there is a problem with a FOB originating city shipment, you still have to pay the vendor and file a claim with the carrier.

Frequency of Inspection
The regularity with which inspections are undertaken. Typically these are:

Annually (once per year)
Bi Annually (twice per year)
Quarterly (four times per year)
Monthly
Weekly
Daily
Once per shift

Fretting
Fretting corrosion (generally referred to as fretting) consists of a chemical reaction activated by relative (sliding) micro movements between steel surfaces. In case of bearings, this movement leads to oxidation of the bore or outer diameter surfaces and becomes visible as powdery rust and/or loss of material. The surfaces become shiny or discolored (blackish - red). The failure develops as a result of poorly fitting (too loose) components operating in combination with high loads and/or accelerations.

Function
A definition of the objective that an equipment item intents to achieve, with respect to its role in the process. The statement should specify the operating context and contain a verb, a noun (object), and a performance standard. For example: “To supply crude oil to the separator V1022 at a flow rate of 60 m³ per hour and a pressure of between 5.5 Bar and 6 Bar.”

Function Check-out
Action taken after maintenance activities to verify that the asset is able to perform the required function.

Functional Failure
A specific failure that refers to the termination of, or degradation in the ability of an item to perform any one of the stated required functions.
See Function.

Future Benefit PM
Preventive maintenance (PM) tasks that are initiated by a breakdown rather than a schedule. The PM is done on a whole machine, assembly line, or process after a section or subsection breaks down. This is a popular method with manufacturing cells where the individual machines are closely coupled. When one machine breaks, the whole cell undergoes a preventive maintenance activity. Future benefit PM is considered "packaging of opportunistic work" given that an opportunity has arisen to do that work (often due to the failure of an associated piece of equipment).

Gantt Chart
A bar chart of scheduled activities that shows the duration and sequence of activities and resources planned.

Go-Line
Used in relation to mobile equipment. Equipment available but not being utilized is typically parked on the go-line. This term is used interchangeably with Ready Line.

Hazard Rate
Hazard rate is the instantaneous speed of failure. Hazard rate is the ratio of failures that occur in an interval to the size of the population at the start of the interval, divided by the length of time.

HACCP
Hazard Analysis and Critical Control Points (HACCP) was started by NASA in conjunction with the Apollo space program to insure astronaut food supplies were safe to consume over the course of their mission. The logic was simple for NASA; keep the astronauts from getting sick during the mission. According to the United States Food and Drug Administration (FDA) HACCP is “a state of the art approach to food safety.” Consisting of seven principles, HACCP outlines the guidance for, and implementation of the food safety program to include both animal and plant products.

HAZOP (Hazard and Operability)
HAZOP stands for a structured technique that may be applied typically to a chemical production process, identifying hazards resulting from potential malfunctions in the process. It is essentially a qualitative process. A HAZOP would typically be undertaken by a multi-disciplinary team, asking a series of "what if?" questions using guidewords representing deviations from the intended process parameters. By undertaking a HAZOP at an early design stage, potential problems can be avoided instead of having to make costly modifications. HAZOP is similar in some respects to Reliability-centered Maintenance (RCM), but not as rigorous in identifying underlying causes of failure, and does not consider the possibility of avoiding such incidents through applying appropriate proactive maintenance tasks.

Hidden Cost
All costs associated with either production or maintenance. When associated with maintenance, hidden costs represent the loss associated with unplanned downtime. Typically, hidden costs represent between 1- 3% of a company’s revenues or, potentially between 30-40% of profits.

Hidden Failure
A failure that does not become evident to the operating crew under normal circumstances. This typically applies to protective devices that are not fail safe (examples include standby plant and equipment, emergency systems, etc.).

HSE
Health, Safety & Environment - generally referring to relevant standards. Specifically in the UK, the abbreviation HSE also stands for “Health and Safety Executive” – a UK Government Department that has an impact upon maintenance (along with all other areas of a business).

HVAC
Heating, Ventilation, and Air Conditioning.

Iatrogenic
Failures that are caused by your own service person(s).

Improvement
Combination of all technical, administrative, and managerial actions intended to decrease the dependency of an asset without changing its required function.

Indentation

An indentation (dent) is a plastic depression caused by debris being pressed into a contact surface. Indentations can go hand in hand with (abrasive) wear. Depending on the hardness of the particle, sharp (often with raised edges) or smooth indentations result.

Infant Mortality
The relatively high conditional probability of failure during the period immediately after an item returns to service.

Inherent Reliability
A measure of the reliability of an item, in its present operating context, assuming adherence to ideal equipment maintenance strategies.
See Reliability.

Inspection
Any task undertaken to determine the condition of equipment, and/or to determine the tools, labor, materials, and equipment required to repair the item.

Inspectors
In a maintenance sense the term refers to the nominated person(s) that has primary responsibility for maintenance tasks. Inspectors can be members of the maintenance department or any other department (machine operators, drivers, security officers, custodians, etc).

Integrated Maintenance Solutions^TM (IMS)
A long-term SKF contract (2 years +) that is generally performance-based. It includes key process actions known internally as the "8 Steps to Maintenance Heaven." An IMS contract brings together all areas of expertise offered by SKF, establishing a continuous process of maintenance monitoring, analysis and improvement. It provides a planned skills transfer program for maintenance and operations personnel, and technology upgrades where required. The services and support best suited to optimize asset efficiency and integrity (safety and environment) are all included under one fixed fee performance based agreement.

Intervention (scheduled / planned)
Action taken systematically in a period of time independent of machine condition. The time period may be fixed (calendar based) or measured according to machine utilization (running hours based).

Intrinsic Safety
Intrinsic safety is intended for products in which the level of electrical energy circulating or stored in the product is insufficient to ignite a surrounding explosive atmosphere even under fault conditions.

Inventory
In accounting terms, inventory is a record of current assets, which includes property and equipment owned (counting merchandise in stock, value of work in progress, and work completed but not sold). In maintenance terms it is frequently used to describe the list of equipment and spare parts currently held in stock.

Inventory Management
The process by which inventory is controlled. Typically this includes:

Tracking usage of stock items
Optimization of stock levels
Control of costs

See Inventory.

IS
See Intrinsic Safety.

ISO
International Standards Organization in Geneva, Switzerland (http://www.iso.org/).
The full and correct title is the International Organization for Standardization.

ISO 9000
An international quality-process auditing program, based on a series of standards published by the International Standards Organization through which manufacturing plants receive certification attesting that their stated quality processes are adhered to in practice.

ISO 14001
International environmental management system (EMS) standard developed by the International Standards Organization. The standard is designed to address all facets of an organization's operations, products and services. It covers environmental policy, resources, training, operations, emergency response, audits, measurement, and management views. It contains five major elements that an organization must satisfy to be registered or certified. These elements are policy, planning, implementation and operations, checking and corrective action, and management review.

Job Card
See Work Order.

Just In Time (JIT)
Used to describe a manufacturing process in which materials arrive as close as possible to the time required. Implementation of "just in time" techniques to reduce lot sizes, reduce setup times, slash work-in-process inventory, reduce waste, minimize non-value-added activities, improve throughput, and reduce manufacturing cycle time. JIT production typically involves use of "pull" signals to initiate production activity, in contrast to work-order ("push") systems in which production scheduling typically is based on forecasted demand rather than actual orders. In many "pull" systems, a customer order/shipment date triggers final assembly, which in turn forces replenishment of component inventory at upstream stages of production.

Kaizen Method
A term originating from Japanese industry relating to a philosophy for continual quality improvement (CQI). Individuals and teams feel empowered to take personal steps toward minimization of:

Defective finished products and inventory (zero defects)
Inefficient work methods, and unnecessary movements and transfers while handling goods
Process and operational weaknesses

KBS
See Knowledge Based Systems.

Key Performance Indicators (KPI)
A select number of key measures that enable performance to be monitored against targets. The KPI will indicate how well the business is doing at attaining its goals. In a manufacturing quality scenario, this may be the amount of scrap or rework that gets metered. In a service quality scenario, such as an insurance company, this may be the open inventory of unprocessed claims. In brand management, market share in itself and in comparison with competing brands is sure to be relevant. In logistics, on-time deliveries, empty return loads, or missing items are candidate indicators.

KM
See Knowledge Management.

Knowledge-Based Systems (KBS)
A wide range of software systems that support decision making for knowledge intensive tasks (i.e. failure diagnosis). The system is based on knowledge that resides in heuristic rules, cases, empirical test results, or partly physical models.
See Expert Systems.

Knowledge Management (KM)
The whole of initiatives and instruments that support creation and flow of knowledge through an organization. This includes initiatives from human resources, information technology, and quality processes. Examples are job rotation, partnering, yellow pages, best practice databases, etc.

KPI
See Key Performance Indicators.

Labor Turnover Rate
A measure of a plant's ability to retain workers, expressed as a percentage of the production workforce that departs annually-or an annualized rate of employee departures. High turnover rates often indicate employee dissatisfaction with either working conditions or compensation.

Labor Per Product (LPP/LPU)
Also known as Labor Per Unit, is calculated using vague estimates of material, Direct Labor, and overhead cost. The cost per unit is normally used for external reporting only, not management decision. Example: Direct labor (operator) X 30% fringe benefits = LPP = LPU.

Latent Fault
An existing fault that has not yet been detected.

LCC
See Life Cycle Costing.

Lean Manufacturing
The systematic identification and elimination of waste to reduce manufacturing or operating costs.

Life Cycle Cost
The total cost of a piece of equipment or system over its entire lifetime; the total of all costs generated or forecasted to be generated during the design, development, production, operation, maintenance, and support processes. Life cycle costs include direct, indirect, recurring, non recurring costs such as acquisition, installation, operating, maintenance, upgrades, and removal or disposal costs.

Life Cycle Costing (LCC)
A process of estimating and assessing the total costs of ownership, operation, maintenance, and disposal costs of a piece of equipment during its projected equipment life. LCC is typically used to compare alternative equipment design or purchase options to select the most appropriate option. LCC is the practice of obtaining over their lifetime the best use of the physical assets at the lowest cost to the entity. This is achieved through a combination of management, financial, engineering and other disciplines.
Life Cycle Costing is sometimes referred to as "Terotechnology" but terotechnology is really the ‘science’ of life cycle costing; it is concerned more with the analysis of component data and derivation of the appropriate component life cycles than with application. Terotechnology is a more common term in manufacturing industry where it is applied to analyzing the life spans of relatively short lived plant and equipment rather than longer lived infrastructure assets.

Loading Time
The available time is derived by subtracting the planned downtime from the available time per day or week, etc.

Loss Of Revenues
Total revenues lost minus direct avoided cost of production (generally materials or energy).

Log Sheet
A document on which brief details of minor activities and repairs are recorded.

Lubricant
A friction reducing substance. A substance, typically oil or grease, applied to a surface to reduce friction between moving parts.

Lubricant Analysis
See oil analysis.

Lubrication Management
Lubrication management at a production facility includes all activities related to the lubrication of machinery. Included, but not limited to, are the following activities:

Establishing a lubrication strategy "where to go, in what period".
Planning for lubrication improvement "projects".
Resource planning: people, tools, software, etc.
Establishing lubrication plan: lubrication selection, schedules, routes, intervals, quantities, etc.
Establishing recording database and reporting system.
Establishing health, environmental, and safety procedures.
Optimizing supply and storage.
Implementation – ensuring the plan and operating procedures are followed.

Lubrication Management is in essence a concentrated effort to evaluate and improve lubrication issues in the plant that will improve returns on plant assets and lower consumption and supply costs. SKF can provide a complete management process that will focus on improving lubrication conditions in the plant, and lower the associated supply and logistic costs.

Maintainability
Maintainability is the probability that a failed component of system will be restored or repaired to a specified condition within a period of time when maintenance is performed according with prescribed procedures. The prescribed maintenance procedures include not only the manner in which repair is to be performed but also the availability of maintenance resources (people, spare parts, tools, and manuals), the preventive maintenance program, skill levels of personnel, and the number of people assigned to the maintenance crew. Restoration times are commonly characterized by the log normal distribution.

Maintainability Improvement
A maintenance engineering activity that looks at the root cause of breakdowns and maintenance problems and designs a repair that prevents future breakdowns. Maintainability improvement places an emphasis on making equipment easier to maintain.

Maintenance
Combination of all technical, administrative, and managerial actions during the life cycle of an asset intended to retain it in, or restore it to, a state in which it can perform the required function (UTEK, 13306:1998 E). So, maintenance covers any activity carried out on an asset to repair equipment, or to ensure the asset continues to perform its intended functions. Maintenance includes all actions taken to prevent or reduce the consequences of failure.

Maintenance Activity
Maintenance activities are the specific actions defined in a Computerized Maintenance Management System (CMMS), taken to prevent or reduce the consequences of failure. For example, component replacement, lubricant analysis, or vibration monitoring are maintenance activities.

Maintenance Categories
Maintenance categories describe the primary function of the maintenance activity. Maintenance categories include the following: inspection, condition monitoring, non-destructive testing, overhauls, and fault finding.

Maintenance Contractor Expenses
Cost of labor and material for contracted maintenance services. This does not include contract labor for capital projects.

(Total) Maintenance Cost
All direct and indirect costs regarding maintenance activities. Direct costs are costs charged to a maintenance budget as fixed costs (e.g. personnel, materials, subcontractors, and overhead). Indirect costs are related to loss of revenue due to unavailability.

Maintenance Engineering
A staff function whose primary responsibility is to ensure maintenance techniques are effective, equipment is designed and modified to improve maintainability, ongoing maintenance technical problems are investigated, and appropriate corrective and improvement actions are taken. Maintenance engineering is often used interchangeably with plant engineering or reliability engineering.

Maintenance Job Plans or Procedures
A job plan is a detailed description of how to implement or undertake a maintenance activity. The term “procedure” is often used to describe job plans, and is commonly used within CMMS’s to describe the individual instructions combined to form a maintenance task.

Maintenance Labor Expenses
Direct pay for maintenance labor including overtime premium.

Maintenance Management
All activities of the management that determine the maintenance objectives, strategies, and responsibilities, and implement them by means, such as maintenance planning, maintenance control and supervision, improvement of methods in the organization, including economical, environmental, and safety aspects (UTEK, 13306:1998 E).

Maintenance Material Expenses
All materials, spare parts, supplies, etc., consumed for maintaining equipment and facility including materials purchased for maintenance by contractors and excluding materials for capital projects.

Maintenance Objectives
Targets assigned and accepted for maintenance activities. Targets may include availability, cost reduction, product quality, environmental preservation, safety, etc.

Maintenance Plan
Structured set of tasks that include the activities, procedures, resources, and time scale required to carry out maintenance.
See Maintenance Schedule.

Maintenance Record
Part of maintenance documentation that contains all failures, faults, and maintenance information related to an asset. This record may also include maintenance cost, asset availability or uptime, and any other data where relevant.

Maintenance/Reliability Engineers
Employees with primary functions of analyzing and resolving maintenance problems, preventive and predictive maintenance, inspection and/or equipment reliability support.

Maintenance Schedule
A list of planned maintenance tasks to be performed during a given time period, together with the expected start times and durations of each task. Schedules apply to different time periods (e.g. daily schedule, weekly schedule, etc.), or to specific plant items (e.g. a machine manufacturer may supply a maintenance schedule with a new machine, related to which is a condition of warranty).

Maintenance Strategy
Management method that covers all aspects of maintenance activities, including firm action plans for achieving maintenance objectives.

Maintenance Strategy Review (MSR)
A systematic review of plant or equipment, evaluating the manner in which it fails within a given operational context, the consequences of failure and the identification of technically feasible and cost effective maintenance strategies to minimize the consequences and or frequency of failure.

Manned Hours
The manned hours represent the hours a production line is manned and planned to be open for production. In case the production is stopped because of unplanned breakdown, operator illness, etc., the hours are still to be counted as manned hours since it was planned to be run.
Remark: In the case production is done in batches, also the time needed for resetting the production channels may be referred to as manned hours. For example, within SKF, the time needed to reset the bearing manufacturing channels is included in the manned hours planning.

Manufacturing Cost
Includes quality-related costs, direct and indirect labor, equipment repair and maintenance, other manufacturing support and overhead, and other costs directly associated with manufacturing operations. It typically does not include purchased-materials costs or costs related to sales and other non-production functions.

Manufacturing Cycle Time
The length of time from the start of production and assembly operations for a particular (finished) product to the completion of all manufacturing, assembly, and testing for that product or specific customer order. (Does not include front-end order-entry time or engineering time spent on customized configuration of non-standard items.)

Manufacturing Resources Planning (MRP)
Software-based Manufacturing Resources Planning systems that translate forecasts into master production schedules, maintain bills of material (lists of product components), create work orders for each step in the production routing, track inventory levels, coordinate materials purchases with production requirements, generate "exception" reports identifying expected material shortages or other potential production problems, record shop-floor data, collect data for financial reporting purposes, and other tasks depending on the configuration of the software.

Mean Downtime
The average time a system is unavailable for use, for example due to a failure. Mean downtime includes the mean repair time plus all delay time associated with a repairman arriving with the appropriate replacement parts.
See Downtime.

Mean Cycles Before Failure (MCBF)
Mean Cycles Between Failures; the average number of equipment cycles between failures; total equipment cycles divided by the total number of failures during those cycles (includes both product and non-product cycles).

Mean Time Between Failures (MTBF)
Mean time between failures is calculated from the total accumulated operating time divided by the number of failures during the same period.

See also Mean Time To Failure (MTTF) for examples.

Mean Time Between Critical Failure (MTBCF)
A measure of system reliability, which includes the effects of any fault tolerance that exist. The average time between failures that cause a loss of a system function defined as “critical” by the customer.

Mean Time Between Maintenance (MTBM)
A basic measure of reliability for repairable fielded systems. The average time between all system maintenance actions. Maintenance actions are for repair or preventive purposes.

Mean Time to Failure (MTTF)
Mean time to failure is calculated from the total elapsed time divided by the total number of failures.

While MTBF excludes time that the equipment is not available or in use, MTTF includes the full period of time regardless of actual operation time. It is common for these two terms to be confused or misunderstood. Failure rates reported or collected from maintenance management systems tend to be in terms of MTTF.
For example, for the rotating components in a machine, when you consider that MTBF is the total actual machine run hours between failures, say the MTBF is 2000 hours, it is not important if this took 1 year or 10 years to accumulate, just that it was 2000 hours. If on the other hand you look at the failure of a non-rotating component like coatings (paint), or metal casting in contact with the coolant or the atmosphere, the total hours the paint has been exposed to the atmosphere or the metal to the coolant is the key. In this instance, the assumption is (assuming MTTF > MTBF) based on how the failure is defined, first sign or rush, or coolant leaking from a hole in the casting. Notice that then the "interpretation" and hence "point of failure" may differ from user to maintainer' etc. If so, the notion of critical, incipient, degraded types of failure can add some detail to that also.
It may be considerable to include the time needed for repair (MTTR) in a MTTF in the case of a coating or casting as illustrated above. The MTTR is not included in MTBF by definition. Imagine a machine is spared, the user may take 1 or 2 months to schedule a repair that could have taken 3 hours. This could significantly skew MTBF.

Mean Time to Repair (MTTR)
MTTR refers to the average total time duration required to physically repair or replace the failed item and to reinstate the operational functionality. Part of the system downtime may be due to time delays (spares, resources), which are not included in the MTTR.

Mean Time to Restore (MTR)
MTR refers to the average (unplanned) system downtime including delays for maintenance and supply resources. This is an appropriate measure when maintenance and supply resources are included as requirement for the maintainability.

Mean Time to Prepare (MTTP)
MTTP is the duration required to prepare for equipment restoration in the event of failure. This time should include all activities and preparations that can be carried out before physical repair activities begin, such as scaffolding, drawing spares from stores, locating tools, spares, and equipment at the job site.
Preparation time should not include lead times required for ordering spares from suppliers. Spare part ordering lead times should be recorded separately to facilitate spares holding policy analysis and the easy identification of long lead times. Although closely related, spares analysis and evaluation is a distinctly different activity to maintenance strategy analysis.

MIMOSA
Machinery Information Management Open Systems Alliance. MIMOSA advocates open exchange of equipment condition related information between condition assessment, process control and maintenance information systems through published, consensus, conventions. This to gain greatest value by combining vital condition information from multiple sources for collective evaluation, reaching accurate determinations of current condition and projected lifetime and communicating results in a useful, understandable form. MIMOSA is committed to preserving the advantages, effectiveness and rich detail contained in specialized applications such as vibration, temperature, lubricating oil and electric motor monitoring and analysis systems within an integrated enterprise information structure. See: http://www.mimosa.org

Mounting (dis-)
Fixing, setting, arranging a component in its intended position. Trained maintenance personnel generally use special, professional equipment for mounting. The mounting tools are based on mechanical, hydraulic, or (induction) heating methods. Dismounting refers to removing the component from its position.

MRO
Maintenance, Repair, and Operations (MRO) products.

MRO Supplier Alliances
Formal negotiated agreements with vendor to supply additional services such as reduced prices, timely delivery, vendor stocking, quality standards, etc.

MTBCF
See Mean Time Between Critical Failure.

MTBF
See Mean Time Between Failure.

MTBM
See Mean Time Between Maintenance.

MTTF
See Mean Time To Failure.

MTTP
See Mean Time To Prepare.

MTTR
See Mean Time To Repair.

No Scheduled Maintenance
An equipment maintenance strategy, where no routine maintenance tasks are performed on the equipment. The only maintenance performed on the equipment is corrective maintenance after the equipment has suffered a failure in the event that a fault becomes apparent (e.g. oil leak, running hot, etc.). Also related to "throwaway maintenance" and "run-to-failure" strategy.

Non-Interruptive Task List
A preventive maintenance task list where all tasks can safely be done without interrupting production.

Non-Operational Consequences
A failure has non-operational consequences if the only impact of the failure is the direct cost of the repair (plus any secondary damage caused to other equipment as a result of the failure).

Non-Routine Maintenance
Any maintenance task not performed at a regular, pre-determined frequency.

Non-Scheduled Time
A period of time when the equipment is not scheduled to be used in production, such as un-worked shifts, weekends, and holidays.

Non-Scheduled Work
Work that isn’t planned or scheduled. Work falls into three categories: 1) emergency, 2) Do It Now (DIN), 3) routine.

Obsolete Store Items
Stock keeping units that have not had activity in three or more years and are not designated as safety stock.

Occupational Safety and Health Administration (OSHA)
A division of the United States Department of Labor. The mission of the Occupational Safety and Health Administration (OSHA) is to save lives, prevent injuries and protect the health of America's workers. To accomplish this, federal and state governments must work in partnership with the more than 100 million working men and women and their six and a half million employers who are covered by the Occupational Safety and Health Act of 1970. (see also: http://www.osha.gov )

OEAM
See Operational Equipment Asset Management.

OEE
See Overall Equipment Effectiveness.

OEM
See Original Equipment Manufacturer.

Oil Analysis
The process of monitoring the condition of equipment through the analysis of oil properties and other lubricants. Typically, oil analysis is conducted through the measurement of particulates in the oil, or the chemical composition of the oil (spectrographic oil analysis). It is commonly used for monitoring the condition of large gearboxes, engines, and transformers.
See Oil Monitoring, and Oil Debris Monitoring.

Oil Debris Monitoring
The analysis of metallic particles that collect in oil to gauge the degree of machine degradation. A variety of techniques may be employed, which include:

Laboratory analysis of collected oil samples
Use of magnetic plugs to collect debris
On-line particle analyzers

Oil Monitoring
Oil monitoring is the practice of regularly checking oil to assess the level of oil degradation to determine the oil’s suitability for continued use as a lubricant, power transmission medium, or coolant. A variety of techniques are typically applied, which include:

Subjective inspection
Use of instrumentation to assess water contamination, viscosity levels, etc.
Laboratory analysis of collected oil samples

On-site Maintenance
Maintenance carried out at the location where the asset is used.

On-time Delivery Rate
The percentage of time that ordered products are received by customers by the specified time or date. Some plants will base this calculation on the date "promised" to customers, but better facilities typically will calculate it against dates "requested" by customers.

Open System
Capable of automatic communication and information exchange without any proprietary or system specific, software links.

Operating Hours
The (accumulated) length of time that an item of equipment is actually operating.

Operational Consequences
A failure has operational consequences if it has a direct adverse impact on operational capability such as lost production, increased production costs, loss of product quality, or reduced customer service.

Operational Efficiency
Used in the calculation of overall equipment effectiveness. The actual output produced from an asset in a given time period divided by the output that would be produced from that asset in that period, had it produced at its maximum rated capacity. Normally expressed as a percentage.

Operational Equipment Asset Management (OEAM)
A comprehensive, fully integrated strategy, process, and culture used to gain the greatest lifetime effectiveness, value profitability, and return from production and manufacturing equipment assets.

Operator Based Maintenance
A philosophy derived from TPM, whereby basic maintenance tasks are performed by operations / production personnel. Typically such activities include cleaning and subjective inspection. Sometimes referred to as Operator Maintenance.

Operator Driven Reliability (ODR)
SKF's Operator Driven Reliability is defined as a company-wide, team-based process, which augments classic operator duties to optimize the operation of industrial production plants. ODR impacts equipment effectiveness by contributing to optimal production and financial return on investment. ODR incorporates operational, technical, and financial metrics, which are balanced to best meet the business plan of the Industrial enterprise.

Original Equipment Manufacturer (OEM)
An OEM (original equipment manufacturer) is a company that build a product that it sells under its own company name. An air compressor manufacturer is an OEM, and the manufacturer of the PLC inside that air compressor is an OEM.

Outage
A term used in some industries (notably power generation), which is equivalent to a planned shutdown. A period of time during which there is a complete planned production stoppage.

Outsourcing
Shifting of production work or support activities to an outside (third-party) supplier.

Overall Equipment Effectiveness (OEE)
A term initially coined in connection with Total Productive Maintenance (TPM). It provides a measure of overall asset productivity, and is generally expressed as a percentage. OEE is calculated by multiplying Availability, Operational Efficiency, and Quality Rate. For example: OEE = 90% availability * 80% operational efficiency * 90% quality performance = 65%.

To get an idea of total efficiency, the overall equipment effectiveness is multiplied with system utilization.
Remark: In case of product variations in one production line, resetting the production line could be necessary. If this can be done without a stop, it is probably translated in speed or yield losses. If this is done during a stop, it could be considered as planned although it can results in a forced (incurred) downtime elsewhere in that production line, which can be considered as unplanned. Now, if the set-ups / resets are foretold / preplanned, then they are part of the planned downtime losses and the issue becomes what was the magnitude, frequency of those set-ups / resets actually when compared to what was allowed for and planned. So, planned resetting can be considered as planned downtime loss, but the next issue is how accurate was our planning, etc. But be careful here, because if the total available time is 'scaled down' then the real scheduled losses are higher! See also Manned Hours.

Overhaul
A comprehensive examination and restoration of an asset to an acceptable condition.

Parts Per Million (PPM)
PPM is a way of stating the performance of a process in terms of actual or projected defective material.

Patterns Of Failure
Failures manifest in one of four primary patterns. They are described below together with their approximate percentage contribution to the whole shown.

Wear out - constant hazard rate with a distinct wear out region
Bathtub - infant mortality, constant hazard rate, and distinct wear out
Constant – constant hazard rate with little or no changes over the life
Infant mortality - infant mortality followed by a constant hazard rate

Infant mortality is clearly the primary failure pattern. Scheduled maintenance activities do little or nothing to defend against the portion of infant mortality failures. Assets where early life failures are a significant problem should be examined using root cause failure analysis.

PdM
See Predictive Maintenance.

Pending Work
Work issued to a mechanic or contractor that is unfinished. It is important to complete all pending work. Pending work may refer to equipment returned to service ‘temporarily’ where further work is required to restore and assure full form, fit, and function. Pending work forms part of backlog, but it is often necessary to segregate and track it separately when referring to temporary modifications.

Performance Based Contracting
In a performance-based contract, the fee paid to the contractor depends (at least partly) on the business results achieved within the contracted work. This means that apart from the quality, speed, etc., of the work itself, the results of positive and negative work achievements is shared. For example, in the case of maintenance contracts, the mutual goal may be reduced mechanical equipment downtime (increased uptime). The benefits are long-term relationship and confidence building, reduced amount of contractors, mutual goals, and sharing the risks of unknown events. Overall cost reductions are mentioned from 9% to 30%. A collection of ten success factors is described.

P-F Interval
A term used in reliability-centered maintenance. The time from when a potential failure (P) is first detected on an asset or component using a selected predictive maintenance task, until the asset or component has failed (F). Reliability-centered maintenance principles state that the frequency with which a predictive maintenance task should be performed is determined by the P-F Interval.

PID
See Proportional Integrative Differential (PID) control.

Planned Downtime
The amount of time officially scheduled in the production plan, which includes, no orders, changeovers and planned maintenance. Planning and scheduling technologies. A variety of software-based advanced planning, scheduling, and optimization systems.

Planned Maintenance
Any maintenance activity for which a pre-determined job procedure is documented, for which all labor, materials, tools, and equipment required to carry out the task are estimated, and their availability assured before commencement of the task.
Planned Maintenance is a term commonly used to describe tasks carried out on a regular, scheduled basis. These tasks may be predictive in nature (routine subjective inspections and/or formal condition monitoring activities), or they may be preventative in nature (cleaning / changing filters, checking/adjusting clearances etc).

Planned Repair Schedule Compliance
The number of planned repair work orders completed from the daily/weekly schedule divided by the total number of work orders on the schedule.

Planning
The process of determining the resources, methods, and processes needed to perform maintenance work efficiently and effectively.

Plant/Project Engineers
Employees with primary function of planning and executing on-site plant projects (capital and expense).

Plant Replacement Value (PRV)
See Estimated Replacement Value (ERV).

PLC
See Programmable Logic Controller.

PM
A term variously used as an acronym for Planned Maintenance or Preventative Maintenance. Sometimes used to describe the Work Order (documentation) associated with a routine maintenance task. This term has different meanings depending upon its context.

Potential Failure
A term used in Reliability-centered Maintenance. An identifiable condition that indicates a functional failure is about to occur, or in the process of occurring.

PRA
See Probability Risk Assessment.

Predictive Maintenance (PdM)
A maintenance process based on machinery inspection, monitoring, and prediction. Machine stops for maintenance are planned depending on the predictions (condition-based). The terms Condition Based Maintenance, On-Condition Maintenance and Predictive Maintenance are often used interchangeably.
See Condition-Based Maintenance.

Preventive Maintenance
A maintenance process based on preventing unexpected events from occurring by employing proper maintenance procedures, clean environment, etc. Maintenance is mostly done during planned machine stops (fixed intervals). Emphasis is placed on replacing, overhauling, or remanufacturing an item at a fixed interval, regardless of its condition at the time. Scheduled restoration tasks and scheduled discard tasks are both examples of Preventive Maintenance tasks.

Preventive Maintenance Schedule Compliance
The number of preventive maintenance work orders completed from the daily/weekly schedule divided by the total number of preventive maintenance work orders on the schedule.

Preventive/Predictive Work
Scheduled, preplanned preventive and predictive (condition-based) inspections and work orders.

Primary Failure
A failure not caused either directly or indirectly by another failure or fault.

Priority
The relative importance of a job. A safety problem has a higher priority than an energy improvement job.

Proactive
Action before a stimulus (opposite of reactive). A proactive maintenance department acts before a breakdown.

Proactive Maintenance
The combination of operator-performed maintenance, preventive maintenance, and predictive maintenance activities whereby maintenance is conducted to prevent, eliminate, delay or reduce maintenance before failure [McKenna, T. and Oliverson, R., "Glossary Of Maintenance And Reliability Terms", Gulf Publishing Company, ISBN 0-88415-360-6 (1997)].
The application of analytical methods, tools, and techniques to eliminate failures, extend component life, mitigate consequences, minimize downtimes, and optimize all resources. It consists of systematic identification and elimination of potential problems in all aspects of reliability, availability and maintainability [Hansen, R.C., "Overall Equipment Effectiveness - A Powerful Production / Maintenance Tool For Increased Profits", Industrial Press, ISBN 0-8311-3138-1 (2001)].

Proactive Reliability Maintenance ^TM (PRM)
SKF defines PRM as a strategy that addresses failures and implements the processes necessary to prevent recurrence. At the process foundation is a systematic method to benchmark asset productivity and implement corrective actions that reduce total life cycle costs. In short, PRM enables an organization to take complete control over what is happening on the plant floor. The SKF Proactive Reliability process is based on four key steps: (1) Predictive Maintenance, (2) Diagnostics and Root Cause Analysis, (3) Key Performance Indicators, and (4) Operational Review.
In industry, PRM is partly compared to design-out maintenance. For example, reactive maintenance only takes action when a pump breaks down, and in a preventive maintenance setting, the pump is cleaned, re-lubricated, etc., at regular intervals (x operating hours). In a predictive maintenance setting, the pump may be monitored on-line. When vibration levels increase, maintenance actions are initiated. Applying design-out maintenance means the pump is "redesigned" with a different type of lubricant or bearing.

Probabilistic Risk Assessment (PRA)
A "top-down" approach used to apportion risk to individual areas of plant and equipment, and possibly to individual assets to achieve an overall target level of risk for a plant, site, or organization. These levels of risk are then used in risk-based techniques, such as reliability-centered maintenance, risk-based maintenance, and Hazop, to assist the development of appropriate equipment maintenance strategies, and to identify required equipment modifications.

Process Control
A General term that refers to the control of any process (i.e. a chemical process).

Process Manufacturing
The manufacturer of products such as chemicals, gasoline, beverages and food products that typically are produced in "batch" quantities rather than discrete units. Many process operations require inputs such as heat, pressure, and time (for thermal or chemical conversion).

Procurement Cycle Time
Total elapsed time from the initiation of a parts requisition until receipt of the part on-site.

Product Data Management (PDM)
Software-based systems that link, manage, and organize product-related data from various sources-both internally and externally (from suppliers)-across various computer platforms, divisions, departments, and geographic locations. PDM incorporates CAD files, manufacturing data, and documents to reduce engineering design times; ensures timely access to consistent up-to-date product information; and improves information flow, cross-functional communications, and support services.

Productivity
The primary definition here is annual dollar value of shipments per employee.

Production Shutdown Mode
A term that describes the mode in which a production process shuts down after a malfunction.
Delayed shutdown: the production shuts down or produces off specification, completely or partially, after a specific time (Production Shutdown Delayed Time, PSDT).
Immediate shutdown: the production shuts down or produces off specification, completely or partially, immediately after the failure occurs.

Productive Time
A period of time when the equipment is performing its intended function. This includes regular production (including loading and unloading of product), rework, work for third parties, and engineering runs done in conjunction with production.

Prognostics Preventive Maintenance Clock
The parameter that initiates the Preventive Maintenance (PM) task list for scheduling (usually buildings and assets in regular use). Assets that are used irregularly may use other production measures such as pieces, machine hours, or cycles. The ability to predict or forecast the future condition of a component, or system of components in terms of failures or degraded condition to satisfactorily conform to operational requirements.

Programmable Logic Controller (PLC)
A Programmable Logic Controller (PLC) is a piece of hardware and embedded software used to control any process machinery. The software needs to be adjusted by a control engineer after applying any control method (e.g., PID control).

Proportional Integrative Differential (PID) Control
Proportional Integrative Differential (PID) control is a straightforward, common automatic control method. The name refers to the manipulation of the signal used for feedback. For example, a temperature measurement signal is fed back to a heater. Simpler alternatives are P, PI or PD control.

QS 9000
A common quality certification program for auto industry suppliers. Developed by the Big Three automakers, it includes ISO 9000 as a baseline.

Quality
Degree to which product characteristics conform to the requirements placed upon that product. This includes reliability, maintainability, and safety. The totality of features and characteristics of a product or service that bear on its ability to satisfy given needs; fitness for use; degree of variation from the target (nominal) value; and conformance to requirements.

Quality Function Deployment (QFD)
A systematic methodology that focuses on exactly translating customer wishes to product changes to process changes. Changes or activities that do not contribute to customer goals are considered wasteful and are eliminated.

Quality Rate
A term used in Total Productive Maintenance (TPM) to indicate the rate of approved product(s) with respect to products that do not comply with the relevant quality standards. Quality rate is expressed as a percentage.

Quick Start Reliability (QSR)
For facilities organized in a classically reactive structure or hierarchy, often with absent or sub-optimized
maintenance/reliability engineering capabilities, SKF offers the Quick Start Reliability program. A basic first step in the evolution of maturity of an operation to the more advanced maturity phases of the complete AEO process, Quick Start Reliability is:

Targeted to those clients that are in the lower maturity phase (firefighting) in the maturity pyramid.
Designed to establish a maintenance process where none exists or is sub-standard.
Focused on the first 90 days of the overall change management plan for maintenance.
Geared to quickly put a performance management culture or process in place.
An 8-step process that identifies a plant’s best “early wins” and implements a program to achieve them.
Built around performing the right work at the right time in the right way—on equipment that is business critical.
The best course of action when a plant has neither the time nor the funding to conduct a comprehensive maintenance strategy review.

RAV
Replacement Asset Value.
See Estimated Replacement Value (ERV).

Raw-Materials Turn Rate
A measure of asset management that typically is calculated by dividing the value of total annual shipments at plant cost (for the most recent full year) by the average raw-material value at plant cost. Plant cost includes material, labor, and plant overhead.

RBM
See Risk-based Maintenance.

RCM
See Reliability-Centered Maintenance.

Reactive Maintenance
Maintenance Strategy to equipment malfunctions or break downs after they occur. Maintenance is mainly performed during irregular non-planned stops. It may be undertaken where equipment is knowingly assigned a Run-To-Failure (RTF) strategy, or No Scheduled Maintenance strategy.
See Run To Failure, Breakdown Maintenance, and No Scheduled Maintenance.

Ready Line
See Go Line.

Redundancy
The existence of one or more means (though not necessarily identical) for accomplishing a given function. Active redundancy has all items operating simultaneously, while standby redundancy has alternate means activated upon failure.

Reengineering
A one time fundamental rethinking and business process redesign to achieve dramatic improvements in performance and/or maintainability.

Relative Losses
The production deferred or lost due to the specified element or system, as a percentage of the total deferment or losses.

Reliability
The probability that equipment, machinery or systems will perform their required functions satisfactorily under specific conditions within a certain time period. This can be measured by mean time between failure (MTBF) - the duration or probability of failure-free performance under stated conditions. The term reliability may also be used to denote the probability of success or success ratio.

Reliability Block Diagram
A pictorial representation of the logical interdependencies (parallel or series paths) required for the system under analysis to function correctly.

Reliability-Centered Maintenance (RCM)
A structured process, originally developed in the airline industry, to determine the equipment maintenance strategies required for any physical asset to ensure that it continues to fulfill its intended functions in its present operating context. The assets are decomposed, extensively analyzed and described, FMEA are made for the most critical components, and the maintenance organization and processes are carefully (re)defined. RCM is particularly useful and feasible for maintenance of identical installations (like aircraft). A certain level of maintenance maturity is required to ensure accurate and complete asset data. A number of books were written on the subject, but none better than Moubray: RCM II, Industrial Press (1997).

Remote Maintenance
Maintenance carried out without physical access of the personnel to the asset.

Reliability Engineering
See Maintenance Engineering.

Replacement Asset Value (RAV)
Replacement asset value is the market cost for asset replacement.
See Current Asset Value(CAV).

Replacement Maintenance (RM)
Replacement / Rehabilitation / Remodel Maintenance. All activity designed to bring an asset back into good shape, upgrade an asset to current technology, or make an asset more productive.

Return On Assets (ROA)
See Return On Net Assets (RONA).

Return On Equity (ROE)
Profit divided by corporate equity.

Return On Investment (ROI)
The profit gained from an investment divided by the monetary value of the investment.

Return On Capital Employed (ROCE)
The capital employed in the business is the sum of the business assets and the operating capital required to support the enterprise. Return on Capital Employed (ROCE) is the ratio between after tax operating profit (Business Operating Income, BOI) and capital employed.

Return On Net Asset (RONA)
The ratio between after tax operating profit, and the net assets value of the enterprise. Net assets comprise the land, building, and equipment owned by the company.

Revealed (Overt) Failure
A component or system failure that is automatically brought to light on occurrence.

Rework
All work that has to be redone. Rework indicates a problem in materials, skills, or scope of the original job.

Risk
Risk is defined as (1) Possibility of loss or injury; (2) Someone or something that creates or suggests a hazard; (3) The chance of loss to the subject matter of an insurance contract; (4) The degree of probability of such loss. Risk is being associated with a possibility of a loss due to a hazard exposure. A hazard is defined as the source of the loss. There is a general baseline that risk includes the two characteristics uncertainty and loss (or gain).

Risk Analysis
The analysis of risk includes two phases, risk assessment and risk management. The risk assessment phase deals with the identification of initiating events towards the construction of the risk curves. The so-called quantitative Probability Risk Assessment (PRA) methodology is often used. PRA can include well-known techniques like preliminary risk analysis, failure modes and effects analysis, criticality analysis, hazards and operability study, event tree analysis, and fault tree analysis. The risk management phase deals with making trade-offs between alternatives influencing the risk scenarios and curves. Each alternative for actively or passively controlling the risk creates a specific risk curve. The curves are evaluated and decisions are made accordingly taking the cost of alternatives as trade-off. A risk-free alternative is often used as a reference point in evaluating alternatives.

Risk-Based Maintenance (RBM)
A maintenance improvement program whereby the maintenance processes and procedures are planned based on (failure) risks, effects, and calculated cost. This is a financially based analysis technique which focuses on establishing the relative worth of maintenance. It was originally developed as a means of reviewing existing maintenance programs, and in this mode it works well as a continuous improvement tool. RBM defines opportunities for incremental improvement through the elimination of tasks of low value and the introduction of tasks which address high commercial risk areas. As such, RBM is also valuable in transferring knowledge from existing installations to provide a baseline for new builds.

Risk-Based Inspection (RBI)
Risk Based Inspection (RBI), as the name suggests, employs similar RBM risk assessment techniques, but differs significantly from RBM in terms of its basis and scope. Risk Based Inspection is concerned primarily with pressure and containment systems including (but not restricted to):

Vessels and boilers
Pressurized and refrigerated storage tanks
Compressors and pumps
Associated pipe work and valves.

Protective devices associated with such systems are also usually included. Risk Based Inspection has an integrity focus. It therefore concerns itself primarily with mitigation of safety and environmental risks.

Root Cause Failure Analysis (RCFA)
Generally stands for a systematic procedure to investigate the root causes of asset failures (failure diagnosis). The diagnosis results are used in maintenance tasks as a proactive way to prevent repetitive failures.

Route Maintenance
A mechanic’s established route through a facility to fix the small problems. The route mechanic is usually very well equipped so he/she can deal with most small problems. Route maintenance and preventive maintenance activity are sometimes combined.

Routine Work
Work done on a routine basis where the work and material content is well known and understood (for example, daily or weekly line start-ups).

Routine Maintenance Task
Any maintenance task performed at a regular, predefined interval.

Run-To-Failure (RTF)
An equipment maintenance strategy, where no routine maintenance tasks are performed on the equipment. The only "planned" maintenance performed on the equipment is corrective maintenance after the equipment has suffered a failure. Run-To-Failure is a conscious decision as opposed to break down maintenance. Also related to "throwaway maintenance" (Run to failure followed by replacement), and "no scheduled maintenance".
See also No Scheduled Maintenance and Break Down Maintenance

Safety-Improvement Programs
Practices intended to constantly improve safety within a plant or across a company, including, but not limited to, safety teams, safety awareness programs and communications, safety "days," safety training, and setting of continuous-improvement goals targeting safety metrics, such as OSHA reportable or lost-workday rates.

Safety Instrumented Function (SIF)
Safety Instrumented Function (SIF) is a safety function with a specified safety integrity level which is necessary to achieve functional safety. A Safety Instrumented Function can be either a safety instrumented protection function, or a safety instrumented control function.

Safety Instrumented System (SIS)
Safety Instrumented System (SIS) is a function to be implemented by a SIF, or other technology safety related system, or external risk reduction facilities, which is intended to achieve or maintain a safe state for the process, with respect to a specific hazardous event. The terms SIS and SIF are often used almost interchangeably. It should be noted, though, that a Safety Instrumented System is a combination of one or more Safety Instrumented Functions.

Safety Integrity Level (SIL)
The Safety Integrity Level (SIL) of a process is a measure of its safety, in terms of the extent to which a user may expect that process to perform safely, and in the case of failure to fail in a safe manner.

SCADA
Supervisory Control And Data Acquisition - SCADA system refers to the combination of telemetry and data acquisition. It consists of collecting information, transferring it back to a central site, carrying out necessary analysis and control, and then displaying this data on a number of operator screens. The SCADA system is used to monitor and control a plant or equipment. Control may be automatic or can be initiated by operator commands. SCADA system incorporates both hardware and software and provides central monitoring and control of plant and facilities. SCADA typically consist of a “master” terminal unit (MTU) and one or more “remote” terminal units (RTU).

Scheduled Downtime
A period of time when the equipment is not available to perform its intended function due to planned downtime events. These include maintenance delay (delay after an interrupt is reported, but before anyone arrives to repair it); production test; preventive maintenance; change of consumables; setup; and facilities-related downtime.

Scheduled Maintenance
Any maintenance work that is planned and included on an approved maintenance schedule.

Scheduled Work
Work written up after an inspection and known about for a fixed period of time (e.g. 1 day) in advance. A maintenance scheduler or planner inputs the work into the schedule. Sometimes the inspection yields work that must be done immediately which becomes emergency or DIN. Scheduled work is part of a planned maintenance or corrective maintenance program.

Scheduling
The process of determining what maintenance jobs gets worked on, when, and by whom based on the priority and resource/equipment availability. This process should take place before the job is executed.

Secondary Failure
A failure caused either directly or indirectly by another failure or fault.

Setup Time
Term used within SKF defining the time that is needed for resetting the channel (production line) from one product type to another. It is measured as the lost production between the start of the reset and running normal production rate for the new type. It is expressed in % of manned hours.

Short Repairs
Repairs that a preventive maintenance or route person can complete in less than 30 minutes with the tools and materials that he/she carries.

Shutdown
Outage scheduled in advance for maintenance or other services. Sometimes called planned outage.

Shutdown Maintenance
Maintenance that is only performed while equipment is shutdown.

Six Sigma Quality Program
Introduced by Motorola in 1988, six sigma stands for an extensive quality improvement program, with the goal to improve customer satisfaction through reducing and eliminating defects. The six sigma target is a 3.4 part per million defect rate, which is perceived as world class performance. As comparison, three sigma stand for 66.8 defects per million.

Soft Foot
Soft foot is a condition in which one of the machine feet does not sit flat on the base. The foot or the base may have been damaged, worn or warped. When you tighten the bolt on the foot, the machinery will distort.

Spare Part
Any component or equipment intended to restore a corresponding one in order to restore the original required function of the component or equipment.

Spare Part Management
See Inventory Management.

SRCM^®
SRCM® - Streamlined Reliability-Centered Maintenance. This enhanced version of RCM focuses on the dominant failure modes of equipment and the significant effects of those failures such as production losses, personnel safety, environmental releases, etc. A key benefit of an SRCM program is developing the understanding of plant personnel on the value of a modern-based maintenance strategy. As such, SRCM is particularly appropriate where a major change in the maintenance culture within the enterprise needs to be made, which also makes it a good option for new builds.

Standard Job Plan
A standard job plan is a generic template for a job that will be done repetitively. Their purpose is to facilitate speedy production of job plans for specific maintenance jobs. The Standard Job Plans approach is in particular applied in the maintenance environment.

Standard Operating Procedure (SOP)
Established or prescribed methods to be followed routinely for the performance of designated operations or in designated situations. Standard Operating Procedures widely used in the production / operations environment.

Standard Industrial Classification (SIC) code
A coding system of the U.S. government used to identify specific economic sectors. Coding for manufacturers encompasses the two-digit numbers of 20 through 39.

Standby Time
A period of time, other than non-scheduled time, when the equipment is in a condition to perform its intended function, facilities are available, but it is not operated. This includes time when no operator is available, time when no product is available (no boards or components), and waiting on upstream or downstream equipment.

Standing/Blanket Work
Small and/or routine and repetitive tasks covered on standing or blanket work orders. Work orders used to cover routine tasks that typically require less than 60 minutes to complete.

Statistical Process Control (SPC)
Use of variation analysis, with manual or computerized control charts, to detect irregular variations in a process as quickly as possible. Often, SPC charts display upper and lower limits for part characteristics or process parameters and show trends over time, indicating when the limits are exceeded (or are about to be exceeded) and corrective actions are needed. In some closed-loop systems, adjustments are made automatically when readings indicate that a control limit is being approached.

Stock Keeping Units
Number of storeroom line items with a planned stock level or one of more units.

Storeroom Inventory
Average value of stores stock carried on plant's book to support maintenance operations (includes capital spares maintained as safety stock). Also referred to as Stores Investment.

Storeroom Inventory Fill Rate
The total number of storeroom issue requests filled 100% divided by the total number of storeroom issue requests.

Storeroom Inventory Turnover
Annual value of storeroom materials used divided by the average storeroom inventory.

Stores Investment
This term stands for the amount of capital invested in spares, strategic parts, and consumables used for maintenance.

String-Based Preventive Maintenance
Usually, this refers to simple preventive maintenance tasks that are strung together on several machines. Examples of string PM’s include lubrication, filter change, or vibration routes.

Subsystem Criticality
A list of all the subsystems within a model, ranked according to the severity of their individual effect on the performance of the system. Each subsystem contains several events, grouped into a common system.

Sudden Failure
A failure that could not be anticipated by previous examination or monitoring.

Supply Chain Management
Supply chain management deals with the management of materials, information, and financial flows in a network consisting of suppliers, manufacturers, distributors, and customers. The coordination and integration of these flows within and across companies are critical in effective supply chain management. The ultimate goal is to manage effectively and efficiently the activities of design, manufacturing, distribution, service, and recycling of their products and services to their customers. (From Stanford University)

Survey
A formal look around. All of the aspects of the facility are recorded and defined. The survey looks at every machine, room, and throughout the grounds. The surveyor notes anything that looks like it needs work.

Symptom
A qualitative or quantitative measure that shows a particular equipment anomaly, directly or indirectly.

Systematic Preventive Maintenance
Maintenance that is planned and programmed in a fixed period of time independent of equipment condition.

Task
One line on a task list that gives the inspector specific instruction to do one thing.

Task List
In a maintenance inspection context, a task list provides directions about what to look for during an inspection. Tasks include inspecting, cleaning, tightening, adjusting, lubricating, replacing, etc. Tasks are specific, complete, and have a performance standard. Avoid ‘ticks’ as the only feedback that a task is completed.

Total Effective Equipment Productivity (TEEP)
The ratio between the actual amount of "in-specification product" produced in a given total time period and the output theoretically available in the same period if the machine operates at its designed operating rate.
The percentage of total (calendar) time the equipment runs at ideal speed making good product.
The product of Asset Utilization, quality rate, and operating speed rate.
Irrespective of the definition used, TEEP measurement takes account of machine availability (with respect to total rather than loading time), quality rate, and performance rate. Therefore, it represents a modified view of OEE based on total time rather than loading time, and arguably provides a more holistic measure of overall effective asset utilization. Inversely, it may be considered as a modified view of asset utilization rate, factored to take account of actual machine performance.

Terotechnology
The application of managerial, financial, engineering, and other skills to extend the operational life of, and increase the efficiency of, equipment and machinery.
"A combination of management, financial, engineering, and other practices applied to physical assets in pursuit of economic life-cycle costs (LCC). Its practice is concerned with specification and design for reliability and maintainability of plant machinery, equipment, buildings, and structures with their installation, commissioning, maintenance, modification, and replacement, and with feedback of information on design, performance, and costs" (from the definition endorsed by the British Standards Institute).

Thermography
The process of monitoring the condition of equipment through the measurement and analysis of heat. Thermography is typically conducted through the use of infrared cameras and associated software. It is commonly used for monitoring the condition of high voltage insulators and electrical connections, which includes refractory in furnaces and boilers, and other applications.

Throwaway Maintenance
This represents a variation on the Run-to-Failure approach. It differs in that the decision is made in advance that the corrective action on failure will always be replacement rather than repair. This is a very common approach to maintenance of electronic components, which often exhibit random failure rates, and for which no repair is feasible.

Time to Re-instate (TTR)
Time required to re-instate equipment back into production at full speed.

Timed Availability
Available for unrestricted operation during a period of time in which operation is required. Sometimes referred to as Total Available Time (be careful total available time is also sometimes referred to as the total number of installed hours, basically being the number of hours in a year).

Total Asset Management
An integrated approach to Asset Management that incorporates elements such as reliability-centered maintenance, total productive maintenance, design of maintainability, design for reliability, value engineering, life cycle costing, probabilistic risk assessment, etc., to arrive at the optimum cost-benefit-risk asset solution to meet any given production requirements.

Total-Productive Maintenance (TPM)
This is a Japanese maintenance improvement program used to change the maintenance processes and culture to increase productivity. It particularly focuses on aspects such as attitude, motivation, responsibilities, and performance of the workforce. Thus, everyone in the company must understand that their job performance impacts the performance of the asset. It empowers operators to take over maintenance tasks. The results are measured by the OEE rate.
TPM is a company wide management program that emphasizes production operator involvement in equipment maintenance, and continuous improvement approaches. Numerous books were written on the subject, including Nakajima’s authoritative introduction, and a more recent update by Peter Willmott.

Total Quality Management (TQM)
A multifaceted, company-wide approach to improving all aspects of quality and customer satisfaction-including fast response and service, as well as product quality. TQM begins with top management and diffuses responsibility to all employees and managers who can have an impact on quality and customer satisfaction. It uses a variety of quality tools such as QFD, Taguchi methods, SPC, corrective-action response teams, cause-and-effect analysis, problem-solving methodologies, and fail-safe-ing (or "poka-yoke" methods).

Total Time
All time during the period being measured (at the rate of 24 hours per day, seven days per week.) Also equal to the sum of time spent in all six equipment time categories.

Tribology
The science and technology of interacting surfaces in relative motion and related practices. Friction, lubrication, and wear sciences and technology (American Society of Engineers).

True Downtime Cost (TDC)
A method of recording and analyzing all significant cost metrics associated with equipment downtime in a building or manufacturing facility. TDC provides a way to assign time and/or monetary value to previously considered “non-tangible” cost of downtime. Also TDC includes downtime factors commonly overlook to arrive at a more true value for the cost of downtime.

Turnaround
A stop, or full or substantial interruption of plant production. Generally turnaround is considered to be a period longer than 24 hours.

Ultrasonic Inspection
A high frequency signal is sent and reflected by the component to be analyzed. Ultrasonic inspection is especially meant to detect early, small fatigue cracks or material structure defects / changes. Also generally applied for leak detection.
See Fatigue.

Unbalance
According to the International Organization for Standardization (ISO) unbalance or imbalance is defined by “that condition which exists in a rotor when a vibratory force or motion is imparted to its bearings as a result of centrifugal force". The effect occurs when a rotor’s mass is unevenly distributed about the axis of rotation. This may be envisaged as a “heavy spot” on the rotor.

Unit
The asset the task list is written for in a preventive maintenance system. The unit is a machine, system, or component of a large machine.

Unplanned Maintenance
Any maintenance activity for which a pre-determined job procedure is not documented, or for which all labor, materials, tools, and equipment required to carry out the task are not estimated, and their availability assured before commencement of the task.

Unscheduled Downtime
A period of time when the equipment is not available to perform its intended function due to unplanned downtime events. These include maintenance delay, repair, change of consumables, out-of-spec input, and facilities-related downtime.

Unscheduled Maintenance
Any maintenance work not included on an approved maintenance schedule prior to its commencement. Note: this is not necessarily a breakdown, rather a break in the schedule of maintenance.

Unrevealed (Covert) Failure
A failure of a component or system that remains undetected until revealed by either proof testing or, more critically, once a demand is placed on the item to function as intended.

Uptime
The time that an item of equipment is in service and can perform its intended function, assuming that the external resources, if required, are provided. Notice that uptime may not be the same as operating time, which is the time that the equipment is performing its intended function.

Useful Life
The maximum length of time that a component is left in service before it starts to experience a rapidly increasing probability of failure. The Useful Life determines the frequency with which a Scheduled Restoration or a Scheduled Discard task should be performed. For Useful Life to hold true, components must, at some consistent point in time, experience a rapidly increasing probability of failure. Research in the airline industry shows that this is only true for 11% of the components in modern aircraft.

User Maintenance (UM)
This is any maintenance request primarily driven by a user. It includes breakdown, routine requests, and DIN jobs.

Utilization
The proportion of available time that an item of equipment is operating. Utilization is calculated by dividing equipment operating hours by equipment available hours, and is generally expressed as a percentage.

Variable Frequency Drive (VFD)
A method of controlling the rotating speed of an electric motor.

Vibration Analysis
A detailed study of the individual characteristics of a machine’s vibrations, with the intention of diagnosing specific machinery faults, usually at an early stage of development. This is typically achieved by studying vibration data in the frequency domain (see FFT) and may also include the study of time domain (time waveform) data. Such analysis may be undertaken routinely as an integral part of a vibration based Predictive Maintenance program. It may also be undertaken for ad-hoc analysis of suspect rotating machinery, irrespective of the machine’s inclusion in a formal monitoring program.

Vibration Monitoring
Regular monitoring of machinery vibrations undertaken as part of a Predictive Maintenance Program. Readings are compared with past levels, with significant change as an indicator of developing machinery faults. The objective is to provide valuable lead-time for maintenance planning. A comprehensive monitoring program usually includes vibration analysis.

Visual Inspection
Visual inspection refers to subjective inspection of machinery, and employs only the human senses. Sometimes it is referred to as “look-listen-feel” checks.

Warning Time
Warning time is considered equivalent to the P-F interval.
See P-F interval.

Wear (abrasive)
Abrasive wear (often referred to as wear) is the progressive removal of material, which results from the ingress, and presence of (foreign) particles (three-body wear). The surfaces become dull to varying degrees. In the case of very fine particles (dust), the surface may become shiny (polished).

Wear (adhesive)
Adhesive wear (also referred to as smearing, skidding, galling) is defined as the transfer of component surface material from a location on one contacting surface to a location on the other contacting surface. The process requires surface-parallel motion (sliding) in the contact, and is often accompanied with high friction heat. Little, or bad lubrication, increases the probability of adhesive wear.

WIP Turn Rate
A measure of the speed at which work-in-process moves through a plant. Typically calculated by dividing the value of total annual shipments at plant cost (for the most recent full year) by the average WIP value at plant cost.

Wireless
In maintenance context, wireless units are defined wireless when they require neither power nor other data wiring. For example, wireless condition monitoring is applied where sensor and communication / analysis module can not be located at the same place.

Work Request
A Formal request to have work done. Work requests are usually tie / date stamped.

Work-In-Process inventory (WIP)
The amount or value of all materials, components, and subassemblies representing partially completed production; anything between the raw material/purchased component stage and finished-goods stage.

Work Order (WO)
Written authorization to proceed with a repair or other activity to preserve a building or asset. Sometimes referred to as a Job Card.

World-class manufacturer
A somewhat arbitrary designation that can be supported by performance results related to various manufacturing metrics. (World-class metrics may vary from one industry to another.) Typically, it denotes "best in class" producers on a worldwide basis. In the broadest sense, world-class manufacturers are those perceived to deliver the greatest value at a given price level.

Wrench Time
A primary measure of workforce efficiency (craft utilization), and of the effectiveness of planning and scheduling functions. It represents time spent actually "performing" maintenance. Surveys consistently show that wrench time (craft utilization) within a reactive, fire fighting maintenance environment is within the range of 30 to 40 percent. A proper planning in the maintenance organization can greatly improve the efficiency of the maintenance execution, generally specified as the wrench time.