Do We Know What We’re Talking About?

EP Editorial Staff | June 17, 2013


Is there a need to define and compile common maintenance terminology into an easy-to-use reference? This author says yes. MT provides the vehicle to deliver it.

 Did you know that even some veterans of the maintenance wars have trouble distinguishing a “rebuild” from an “overhaul”? Many struggle with the question of whether or not “overhaul” falls into the category of preventive maintenance. Still others wonder if “PM” means planned maintenance, predictive maintenance, preventive maintenance or periodic maintenance—and may be confused further with the acronym “PdM.” And how many in our field think that “CMMS” means a magical solution that’s somehow exclusive to managing maintenance? 

If we in maintenance are this confused, what must our customers in operations think? Consider, too, the managers of some plants who, according to word on the street, might still be characterizing our activities as “seat of the pants.” Moreover, how about those folks in the warehouse and purchasing whose services we count on: What must they be thinking? (One warehouse manager accurately observed that while inventory control universally defines a “reorder point,” maintenance “speaks with several tongues.”)

Do we need to sort out our terminology and advise all parties with whom we deal? I vote “yes.” While it’s been a desired goal for some time (one that many of us have discussed off and on for years), with so many new, inexperienced workers entering our field, the need to formally define terms used in our  vernacular is becoming ever more critical. How, though, do we begin? 

A good starting point is what you see here: a list of some of “our” terminology definitions—a glossary of sorts—that allows for review, revision, addition to and combination into other lists. The end result can be a truly “evergreen” document, something that Maintenance Technology has agreed to host here.

To contribute to the glossary, simply click here or scroll down to the bottom of this article. 


adjustments — Minor tune-up actions requiring hand tools, no parts and less than a half hour of time.

administrative information – Information used to communicate within maintenance and operate the maintenance information system.

area organization – A type of maintenance organization in which one supervisor is responsible for all maintenance within a reasonably sized geographical plant area.

autonomous maintenance — Performance of maintenance-related activities such as cleaning, adjustment, lubrication, minor repairs or simple machine calibration by equipment operators. (a cornerstone of total productive maintenance [TPM]). 


backlog — The total number of estimated man-hours, by craft, required to perform all identified, but incomplete, planned and scheduled work.

benchmarking — The systematic process of searching for best practices, innova-tive ideas and highly effective procedures that lead to superior performance.


capital-funded – The funding authorization for nonmaintenance project work such as construction or new equipment installation.

capitalized — Funding for work that expands the plant operating capacity; gains economic advantage; replaces worn, damaged or obsolete equipment; satisfies a safety requirement; or meets a basic need.

category of work – The types of work that make up the work load performed by maintenance: preventive maintenance, emergency repairs, and so forth.

component – A subelement of a unit of equipment such as the belt of a conveyor, the motor of a crusher, or the engine of a truck.

concept – The means by which a major program, such as maintenance, is carried out in relationship to its objective and the other programs that it supports (operations) or on which it depends (purchasing).

condition-based – Actions taken based on the condition of the equipment.

condition monitoring – The application of predictive maintenance techniques on a continuous, periodic, or on-demand basis to determine current equip­ment condition.

coordination – Daily adjustment of maintenance actions to achieve the best short-term use of resources or to accommodate changes in operation needs.

cost center — A department or area in which equipment operates or in which functions are carried out.

culture (of maintenance) – The prevailing knowledge, beliefs, and behavior of a specific group of people (e.g., maintenance). The view of others outside the group that describes their understanding of the others’ knowledge, beliefs, and behavior. A stereotyping of a group.


decision-making information Details necessary to control day-to-day maintenance and determine current and long-term cost and performance trends for management decisions.

deferred maintenance Maintenance that can be postponed to some future date without further deterioration of equipment.

downsizing – The conversion of a larger organization into a smaller one while taking necessary actions to preserve the efficiency and effectiveness of the organization.

downtime — Period during which equipment cannot be operated to perform its intended function.


empowerment – To allow employees a definitive role in the control of their activities.

engineering work order (EWO) — A control document authorizing use of the maintenance workforce or a contractor for engineering project work such as construction.

equipment life cycle — Encompasses selection, purchasing, commissioning, testing, operating, maintaining, overhauling, modifying and replacing equipment.

equipment management strategy A fully coordinated, mutually supporting effort of every plant department and individual to achieve maximum reliability and productive capacity of critical equipment throughout its entire life cycle. 

expensed – Maintenance work charged to the operating budget.


failure analysis — The study of equipment failure data and related field experiences to determine the source of chronic, repetitive equipment problems and the determination of actions to reduce or eliminate them.

failure coding – An indexing of the causes of equipment failure on which corrective actions can be based.

failure modes and effects analysis (FMEA) — Procedure that studies failure causes and ranks their risk, then applies the best technology to reduce occurrences while improving detection capabilities.

forecasting – A projection of anticipated major tasks that are predictable based on historical data.

function – An activity carried out on a unit or performed within a cost center, such as “power sweeping in department 06.”


guidelines – General guidance provided by management as maintenance or other departments carry out their day-to-day functions. See also policies.


inspection – The checking of equipment to determine repair needs and their urgency.

ISO 9000 — A set of quality-assurance standards that can be applied to any organization regardless of size or type. Used to develop a common approach to obtaining quality service or product.


level of service — The degree of maintenance performed to meet desired levels of equipment performance. A high level ensures little chance of failure, whereas a low level meets minimum requirements, risking breakdowns on less-critical equipment.

life-cycle costing The cost incurred during the life-span of equipment to keep it in optimum operating condition. 


maintainability – The degree to which equipment is able to be maintained effectively. Factors influencing maintainability might include simplicity, ease of ac­cess to its critical components, minimum degree of difficulty in replacing components or ease of carrying out common activities like lubrication. Other factors include alarms or signals alerting personnel to problems that, when corrected early, simplify repairs by making them less serious.

maintenance engineering – The use of engineering techniques to ensure equipment reliability and maintainability.

maintenance information system – A means by which field data are converted into information so that maintenance can determine work needed, control the work, and measure the effectiveness of the work done.

maintenance work order (MWO) — Formal document for controlling planned and scheduled work.

maintenance work request (MWR) — Informal document for requesting unscheduled or emergency work. Also called a job ticket or job request.

major repairs Extensive, non-routine, scheduled work requiring the deliberate shutdown of equipment, the use of a repair crew (possibly covering several elapsed shifts), significant materials, rigging and, if needed, lifting equipment.

material coordinator – The person assigned to planning staff who is responsible for the procurement of all materials required for planned work.

mean time before failure (MTBF) — Average time between replacements of a specific component on a designated type of equipment. Also referred to as the life span of a component. Extended MTBF indicates successful actions in extending component life span such as more planned work.

minor repairs — Repairs usually performed by one person using hand tools, few parts and usually completed in less than two hours.

multicraft – Requires personnel to possess more than one craft.

multiskilled – Maintenance that blends necessary craft skills allowing personnel to do a job from start to finish. Also refers to flexible trades, cross-trades, and multicraft maintenance.


nondestructive testing (NDT) The use of technologies to detect cracks, flaws or porosity in components, structures, frames or components. Techniques include magnetic-particle, liquid-dye-penetrant, ultrasonic, eddy-current and radiographic testing. See also predictive maintenance (PdM).


objective – The principal purpose for the existence of each line department (e.g., maintenance) or staff department (e.g., purchasing) and the roles they must play to ensure that the plant production strategy is achieved.

oil analysis – Spectrometric analysis to identify wear particles from the equipment and physical tests to provide information about the lubricant being evalu­ated.

on-condition status Following  discovery of a potential failure, equipment is left in operation on condition that it can continue to perform its intended function. Equipment condition is monitored carefully during this period to preclude sudden deterioration to a functional failure.

overhaul Process during which a piece of equipment must be removed from service and subjected to inspection, teardown and repair of the total unit to restore it to effective operating condition in accordance with current design specifications. See also rebuild.


performance indices – Ratios which convey short-term accomplishments and long-term trends against desired standards.

periodic maintenance — Maintenance actions carried out at regular intervals. Intervals may be fixed (e.g., every six months) or variable (e.g., every 4500 operating hours).

P–F curve — A down parabolic shaped curve denoting the deterioration of equipment condition from the discovery of a potential failure (P) to a functional failure (F).

P–F interval — The elapsed time between the discovery of a potential failure (P) until a functional failure (F) occurs, if no corrective action is taken.

physical testing – Physical testing as with an oil sample to reveal how the lubricant performs. If lubricant contamination is found, the lubricant is changed be­fore further wear occurs.

planning — Determination of resources needed and the development of anticipated actions necessary to perform a scheduled major job.

policies – Management guidelines for the development of field procedures to ensure achievement of plant profitability. See also guidelines.

predictive maintenance (PdM) Techniques to predict wear rate, determine state of deterioration, monitor condition or predict failure.

preventive maintenance (PM) Performance of services to avoid premature equipment failure and extend equipment life, specifically, equipment inspection testing, and condition monitoring to ensure the early detection of equipment deficiencies and lubrication, cleaning, adjusting, calibration and minor component replacements to extend equipment life.

principles – Logic, common sense, proven procedures, or essential rules on which plant operation must be based.

proactive maintenance — The application of investigative and corrective technologies to reduce failures, improve equipment performance and extend equip-ment life. The following analytical tools are associated with proactive maintenance: root cause failure analysis, failure modes and effects analysis and risk-based inspections. Also, the intensive application of positive, aggressive maintenance steps to actively defeat potential failures. 

procedure – The day-to-day method for carrying out elements of the maintenance program such as job assignment and work control; established steps to carry out a task.

production strategy – The manager’s plan for achieving plant profitability. Also called an operating plan or business plan.

productivity – The percentage of time that maintenance personnel are at the work site, with their tools, performing productive work during a scheduled working period.

program – A plan under which action can be taken toward a goal.

program (maintenance) – The interaction of the total plant population as they request or identify work; classify it to determine the best reaction; then plan (as required), schedule, assign, control, and measure the resulting work; and finally, assess overall accomplishment against goals such as performance standards and budgets.

priority – The relative importance of a single job in relationship to other jobs, operational needs, safety, equipment condition, and so on, and the time within which the job should be completed.

project – A definitive objective to build or construct a new capital entity. The installation or modification of major equipment.

project work – Actions such as construction, equipment modification, installation, or relocation to gain economic advantage; replacement of worn, damaged, or obsolete equipment; satisfaction of a safety requirement; attainment of additional operating capacity or the meeting of a basic need. Work is usually capital-funded.

purchase order (PO) – The authorized document for obtaining direct charge materials or services from vendors or contractors.


quality standard — A standardized procedure for accomplishing a major maintenance task in the best way.

quantity standard — The resources required to meet the prescribed quality standard.


random sampling – A statistical technique of data gathering based on the laws of probability. Observations made at random times yield a picture of what happens most of the time. More observations provide a more reliable picture.

rebuild — The repair of a component to restore it to serviceable condition in accordance with current design specifications. See also overhaul.

relocate – To move fixed equipment to a different location.

reliability – The overall condition of production equipment measured by the extended life-span of internal components.

reliability centered maintenance (RCM) A strategy for achieving max-imum equipment reliability and extended life at the least cost. Implementation identifies specific equipment functions in their exact operating context. Then, equipment performance standards are identified for each function and failures are defined when performance standards are not met. Based on the consequences of failures, a maintenance program featuring condition-monitoring techniques is applied to identify potential failures (equipment is starting to fail) accurately and quickly to preclude its deterioration to functional failure (equipment no longer operates) levels. Thus, equipment life is extended and the consequences of functional failures are reduced or avoided. See also P–F curve, P–F interval, on-condition status.

reliability engineering — Actions taken through use of information, field experience and engineering techniques to design or redesign equipment to reduce or eliminate faults that imperil equipment reliability.

repair history – A chronological record of significant repairs made on key equipment used to spot chronic, repetitive problems, failure patterns, and component life-span, which in turn identifies corrective actions and helps forecast component replacements.

repetitive maintenance — Maintenance jobs with a known labor and material content that occur at a regular interval.

reposition – To move mobile equipment to a new working location.

Risk-based inspection – Guides decisions in selecting equipment that possesses the greatest risk of failure if inspections are not done by ranking the equipment according to its probability and consequences of failure. Then the most essential inspection services are contrasted against the raking of equipment to allow the best allocation of resources to meet the basic inspection needs. Risk-based inspection applies primarily to piping.

risk priority number (RPN) — In a failure modes and effects analysis, an RPN is assigned to the failures related to the equipment being studied to establish the priority of corrective actions. RPN = severity × occurrence × detection capability. See also failure modes and effects analysis.

root cause failure analysis (RCFA) — Actions to discover why a failure happened and determine corrective actions to eliminate the failure or reduce its impact.

routine maintenance – Maintenance or services performed consistently in the same manner.


schedule compliance – The effectiveness with which an approved schedule was carried out. Reported as the percentage of jobs completed versus those scheduled.

scheduling — Determination of the best time to perform a planned maintenance job to appreciate operational needs for equipment or facilities and the best use of maintenance resources.

self-directed team – A team of personnel in which each member shares equally in decision making, control, conduct of work, and the accountability for results.

specifications – Technical definition of equipment configuration or performance requirements to meet intended utilization of equipment or materials.

standard — A goal or ideal target to be met. Quality standards prescribe the end product. Quantity standards prescribe the amount of resources required to carry out specific work under normal conditions.

standard operating procedures – A written procedure used to ensure reasonable uniformity each time a significant task is performed.

standing work order — A reference number used to identify a routine, repetitive action.

stock issue card — The authorized accounting document for making stock material withdrawals or returns.

strategy — A global, corporate or plantwide plan to secure a major objective, such as the successful implementation of total productive maintenance. 

system – Standard procedures to accomplish tasks in an organized way.


team (maintenance) – A group of maintenance personnel with complementary skills who are mutually accountable for a common goal of effective mainte­nance and committed to quality performance.

team coordinator – The focal point of work control within a team. Often rotated to ensure that team orientation is preserved.

time-based – Repetitive actions taken based on the passage of a specific time period or the accumulation of a certain number of operating hours or unit of product (e.g., tons).

time card — Authorized accounting document for reporting the use of labor data.

total productive maintenance (TPM) — Productive maintenance carried out by all employees through small-group activities (e.g., quipment maintenance performed on a plantwide basis).

type – All equipment of the same kind: conveyors, pumps, haulage trucks, loaders, and so forth.


unit – One piece of equipment of a specific type (e.g., conveyor 006).

utilization — Percentage of time that a maintenance crew is available to perform productive work during a scheduled working period or shift.


verbal orders — A means of assigning emergency work when reaction time doesn’t permit preparation of a work-order document. 


work force – The personnel who carry out the maintenance work load.

work load – The essential work to be performed by maintenance and the conversion of this data into a work force of the proper size and craft composition, work­ing at reasonable productivity, to ensure the maintenance program is carried out effectively.

work-order system — A communications system by which maintenance work is requested or identified, classified, planned, scheduled, assigned and controlled.


Help build this base of knowledge
See an expanded version of this beginning maintenance glossary at www.mt-online.com/glossary. There, you’ll also find instructions on how to contribute more definitions and/or add to existing ones. Please do. MT

Paul D. Tomlingson is the Principal of Paul D. Tomlingson Associates, Inc., based in Denver, CO. 82+-years-young, he’s been working as a worldwide maintenance consultant for almost 45 years.  Email: pdtmtc@msn.com.




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