Complete maintenance management glossary.

                                                                                    By Joel Levitt

Autonomous Maintenance: Routine maintenance and PM's are carried out by operators in independent groups. These groups solve problems without management intervention. The maintenance department is called for bigger problems that require more resources, technology or downtime.


Asset: Either a machine, building or a system. . It could be a machine, piece of equipment, area (floor in a building), product production line, or even a major component. It is the basic unit of maintenance and the driver of the PM and computerized maintenance systems.


Backlog: All work for the maintenance department that has been formally identified with a work order. While in Backlog identified work is approved, parts are either stocked or bought, and (in ready backlog) everything is ready to go.


BNF equipment: Equipment left off of the PM system, left in the Bust 'N Fix mode (it busts and you fix- no PM at all). BNF is a choice used when PM is not advantageous.


Capital spares: Usually large, expense, long lead-time parts that are capitalized (not expensed) on the books and depreciated. They are kept for protection from excessive downtime.


Call back: Job where maintenance person is called back because the asset broke again or the job wasn't finished the first time. See rework.

Cause: (Special to FMECA) A Cause is the means by which a particular element of the design or process results in a Failure Mode.

Charge-back: Maintenance work that is charged to the user. All work orders should be costed and billed back to the user's department.  The maintenance budget is then included with the user budgets. Also calling rebilling.


Charge rate:  This is the rate that you charge for a mechanic's time. In addition to the direct wages you add benefits and overhead (such as supervision, clerical support, shop tools, truck expenses, and supplies). You might pay a tradesperson $25.00/hr and use a $65/hr or greater, charge rate. Important to compare your cost of doing a large maintenance job or using a contractor.



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


Core damage: When a normally rebuildable component is damaged so badly that it cannot be repaired.


Corrective maintenance (CM): Maintenance activity that restores an asset to a preserved condition. CM is normally initiated as a result of a scheduled PM or PdM inspection.  See planned work also.


Criticality (Special to FMECA): The Criticality rating is the mathematical product of the Severity and Occurrence ratings. Criticality = (S) × (O). This number is used to place priority on items that require additional quality planning.

Customer: Customers are internal and external departments, people, and processes that will be adversely affected by product failure.

Deferred maintenance: This is all of the work you know needs to be done that you choose not to do. You put it off, usually in hope of retiring the asset or getting authorization to do a major job that will include the deferred items. You worry the asset will fail before you get to it.


Detection (Special to FMECA):  Detection is an assessment of the likelihood that the Current Controls (design and process) will detect the Cause of the Failure Mode or the Failure Mode itself, thus preventing it from reaching the Customer.

DIN work: ‘Do It Now’ is non-emergency work that you have to do now. An example would be moving furniture in the executive wing.

Effect Cause: (Special to FMECA) A Cause is the means by which a particular element of the design or process results in a Failure Mode. An Effect is an adverse consequence that the Customer might experience. The Customer could be the next operation, subsequent operations, or the end user.

Emergency work or emergent work: Maintenance work requiring immediate response from the maintenance staff. Emergent work also refers to work that emerges after you open up an asset (pump, vessel, etc). Emergency work is usually associated with some kind of danger, safety, damage, downtime or major production problems.


FMEA Element: FMEA elements are identified or analyzed in the FMEA process. Common examples are Functions, Failure Modes, Causes, Effects, Controls, and Actions. FMEA elements appear as column headings in the output form.

Failure Mode: Failure Modes are sometimes described as categories of failure. A potential Failure Mode describes the way in which a product or process could fail to perform its desired function (design intent or performance requirements) as described by the needs, wants, and expectations of the internal and external Customers.

Feedback: (When used in the maintenance PM sense) Information from your individual failure history is accounted for in the task list. The list is increased in depth or frequency when failure history is high and decreased when it is low.


Frequency of Inspection: How often do you do the inspections? What criteria do you use to initiate the inspection?  See PM clock.


Function: A Function could be any intended purpose of a product or process. FMEA or RCM functions are best described in verb-noun format with engineering specifications.

Future Benefit PM: PM task lists that are initiated by a breakdown rather then a usual schedule. The PM is done on a whole machine, assembly line, or process after a section or sub-section breaks down. This is a popular method with manufacturing cells where the individual machines are closely coupled. When one machine breaks then the whole cell is PM'ed.


GLO (Generalized Learning Objective): Are the general items necessary to know to be successful in a job.  Each job description would be made up of a series of GLO's.


Iatragentic: This describes failures that are caused by your service person.


In-box:  Maintenance jobs not ready to release to the mechanic. You haven't approved, gotten money, parts are on order and not in or other problem. In-box jobs are the first step of the maintenance work order process before the job is reviewed and entered into backlog.


Inspectors: The special crew or special role that has primary responsibility for PMs and PdMs. Inspectors can be members of the maintenance department or can be members of any related department (machine operators, calibration, drivers, security officers, custodians, etc.) 


Interruptive (task): Any PM task, which interrupts the normal operation of a machine, system or asset and required maintenance to take custody of the asset.


Labor: Physical effort a person has to expend to repair, inspect, or deal with a problem. Expressed in hours and can be divided by crafts or skills.


Life Cycle: This denotes the stage in life of the asset. Three life cycles or stages are recognized by the author: start-up, wealth, and breakdown.


Life cycle cost (LCC): A total of all costs through all of the life cycles. Costs should include PM, repair (labor & parts & supplies), downtime, energy, ownership, overhead. An adjustment can be made for the time value of money.


MTBF (Mean Time Between Failures): Important calculation to help set-up PCR schedules and to determine reliability of a system.


MTTR (Mean Time to Repair): This calculation helps determine the cost of a typical failure. It also can be used to track skill level, training effectiveness and effectiveness of maintenance improvements.


Maintenance: The dictionary definition is  "the act of holding or keeping in a preserved state."  The dictionary doesn't say anything about repairs. It presumes that we are acting in such a way to avoid the failure by preserving the asset.


Maintenance Prevention:  Maintenance free designs resulting from increased effectiveness in the initial design of the equipment.


Maintainability Improvement:  Also Maintenance Improvement. This is an activity that looks at the root cause of breakdowns and maintenance problems and designs a repair that prevents breakdowns in the future.  Also includes improvements to make the equipment more easily maintained.


Maintenance: The dictionary definition is "the act of holding or keeping in a preserved state."  The dictionary doesn't say anything about repairs. It presumes that we are acting in such a way to avoid the failure by preserving the asset.


Non-interruptive task: PM task that can safely be done without interrupting production of the machine.


Non-Scheduled work: Work that you didn't know about and plan for at least the day before. Falls into three categories: 1. Emergency   2. DIN   3. Routine   Also work that you knew about but didn’t think about in a systematic way and didn’t add to a schedule.


Occurrence:  Occurrence is an assessment of the likelihood that a particular Cause will happen and result in the Failure Mode during the intended life and use of the product.

OEM- Original Equipment Manufacturer


PCR: Planned Component Replacement. Maintenance schedules component replacement to a schedule based on MTBF, downtime costs and other factors. Technique for ultra-high reliability favored by the aircraft industry.


Parts: All of the supplies, machine parts and materials to repair an asset, or a system in or around an asset.


Planned maintenance: Maintenance jobs for which all resources have been identified. Once the resources are written into the planned job package and backlog relief hours are available the job can be scheduled for execution. Also see scheduled work


PM: Preventive Maintenance is a series of tasks that either, 1. Extend the life of an asset.  2. Detect that an asset has had critical wear and is going to fail or break down. 


PM Clock: The parameter that initiates the PM task list for scheduling. Usually buildings and assets in regular use days (For example, PM every 90 days) as the clock.   Assets used irregularly may use other production measures such as pieces, machine hours or cycles.


PM  frequency: How often the PM task list will be done. The frequency is driven by the PM clock. See frequency of inspection.


Predictive Maintenance: Maintenance techniques that inspect an asset to predict if a failure will occur. For example, an infrared survey might be done of an electrical distribution system looking for hot spots (which would be likely to fail). In industry predictive maintenance is usually associated with advanced technology such as infrared or vibration analysis.


Priority: The relative importance of the job. A safety problem would come before an energy improvement job.


Proactive: Action before a stimulus (Antonym: reactive). A proactive maintenance department takes actions before a breakdown.


RCM: Reliability-centered Maintenance. A maintenance strategy designed to uncover the causes and consequences of breakdown. RCM sets up the priority by the severity of the consequences. PM tasks and redesign are directed specifically at those hi consequence failure modes.  RCM is a procedure for uncovering and overcoming important failures.


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 efficient/productive.


Reason for write-up (also called reason for repair): Why the work order was initiated. Reasons could include PM activity, capital improvements, breakdown, vandalism, and any others needed in that industry.


Rework: All work that has to be done over. Rework is bad and indicates a problem in materials, skills, or scope of the original job. See call back.


Risk Priority Number:  The Risk Priority Number is a mathematical product of the numerical Severity, Occurrence, and Detection ratings. RPN = (S) *  (O) *  (D). This number is used to place priority on items than require additional quality planning.

Root cause (and root cause analysis): The root cause is the underlying cause of a problem. For example you can snake out an old cast or galvanized sewer line every month and never be confident that it will stay open. The root cause is the hardened buildup inside the pipes. Analysis would study the slow drainage problem and figure out what was wrong and also estimate the cost of leaving it in place. Some problems (not usually this type of example) should not be fixed. Root cause analysis will show this.


Route maintenance: Mechanic has an established route through your facility to fix all the little problems reported to them. The route mechanic is usually very well equipped so they can deal with most small problems. Route maintenance and  PM activity are sometimes combined.


Routine work: Work that is done on a routine basis where the work and material content is well known and understood. Example is daily line start-ups.


SLO: Specific Learning Objective is the detailed knowledge, skill or attitude necessary to know to be able to do a job.


SM: Seasonal Maintenance. All maintenance activities that are related to time of year or time in business cycle. Cleaning roof drains of leaves after the autumn would be a seasonal demand.  A swimming pool chemical company might have some November activities to prepare for the next season.


SWO: Standing Work Order, Work order for routine work. A standing work order will stay open for a week, month or more. The SWO for daily furnace inspection might stay open for a whole month.


Scheduled work: Work that has been planned and is written on a schedule at least a few days in advance. Many writers use the phrase, planned maintenance to refer to maintenance work that is both planned and scheduled.


Severity: Severity is an assessment of how serious the Effect of the potential Failure Mode is on the Customer.

Short Repairs: Repairs that a PM or route person can do in less than 30 minutes with the tools and materials that they carry. These are complete repairs and are distinct from temporary repairs.


String based PM: Usually simple PM tasks that are strung together on several machines. Examples of string PM's would include lubrication, filter change, or vibration routes.


Survey: A formal look around at the overall condition of all assets. All of the aspects of the facility are recorded and defined. The survey will look at every machine, room and through-out the grounds. The surveyor will note any thing that looks like it needs work.


TPM: Total Productive Maintenance. TPM is a maintenance system set-up to eliminate all of the barriers to and losses to production. TPM identifies production losses and using teams solves the problems causing the waste. It uses autonomous maintenance teams (focusing on operators) to carry out most basic maintenance activity.


Technical Library (Maintenance Technical Library): The repository of all maintenance information including (but only limited by your creativity and space) maintenance manuals, drawings, old notes on the asset, repair history, vendor catalogs, MSDS, PM information, engineering books, shop manuals, etc. The maintenance technical library could be virtual (entirely on computer).


Task:  One line on a task list (see below) that gives the inspector specific instruction to do one thing.


Task List: It contains directions to the inspector about what to look for during that inspection. Tasks could be inspect, clean, tighten, adjust, lubricate, replace, etc.


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


Unit: Also see asset. The unit can be a machine, a system, or even a component of a large machine. See asset.


Work Order: Written authorization to proceed with a repair or other activity to preserve an asset.


Work request:  Formal request to have work done. Work requests are generally filled out by a maintenance user. Work requests are usually time/date stamped and are the basis of the work orders. 



Executive Summary


This is the complete glossary of common terms used in Maintenance. Terms included in this glossary are:
Autonomous Maintenance, Asset, Backlog, BNF equipment, Capital spares, Call back, Cause, Charge – back, Charge rate, Continuous Improvement (in maintenance), Core damage, Corrective maintenance (CM), Criticality (Special to FMECA), Customer, Deferred maintenance, Detection (Special to FMECA), DIN work, Effect Cause, Emergency work, FMEA Element, Failure Mode, Feedback, Frequency of Inspection, Function, Future Benefit PM, GLO (Generalized Learning Objective),…..

This is the complete glossary of common terms used in Maintenance. Terms included in this glossary are:Autonomous Maintenance, Asset, Backlog, BNF equipment, Capital spares, Call back, Cause, Charge – back, Charge rate, Continuous Improvement (in maintenance), Core damage, Corrective maintenance (CM), Criticality (Special to FMECA), Customer, Deferred maintenance, Detection (Special to FMECA), DIN work, Effect Cause, Emergency work, FMEA Element, Failure Mode, Feedback, Frequency of Inspection, Function, Future Benefit PM, GLO (Generalized Learning Objective),…..

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