Age Exploration The process of determining the most effective intervals for maintenance tasks. Its called age exploration because it is often associated with identifying age related maintenance actions such as overhaul and discard tasks and then extending the interval between tasks.
Availability (1) Informally, the time a machine or system is available for use. (2) From the Overall Equipment Effectiveness calculation, the actual run time of a machine or system divided by the scheduled run time. Note that Availability differs slightly from Asset Utilization
(Uptime) in that scheduled run time varies between facilities and is changed by factors such as scheduled maintenance actions, logistics, or administrative delays.
Benchmarking To seek out the best examples of methods, processes, procedures, and products in order to establish a standard and assess ones own performance in terms of quality, productivity, or cost.
B-Life The time at which a set percentage of failures are expected. For example, the B1 life is when 1% of the units being examined will have failed; B10 is when 10% of the units will have failed.
Building Commissioning The systematic process for achieving, verifying, and documenting that the performance of NASA Faculties and Collateral Equipment meets the design intent. The process extends through all phases of a project and culminates with occupancy and operation.
The process includes the testing and accepting of new or repaired building, system or component parts to verify proper installation.
Calibration A scheduled maintenance task characterized as an Inspection. See Inspection.
Collateral Equipment Encompasses building-type equipment, built-in equipment, and large, substantially affixed equipment/property and is normally acquired and installed as part of a facility project as described below (also see Non-collateral Equipment):
Building-Type Equipment. A term used in connection with facility projects to connote that equipment normally required to make a facility useful and operable. It is built in or affixed to the facility in such a manner that removal would impair the usefulness, safety, or environment of the facility. Such equipment includes elevators; heating, ventilating and air conditioning systems; transformers; compressors; and other like items generally accepted as being an inherent part of a building or structure and essential to its utility. It also includes general building systems and subsystems such as electrical, plumbing, pneumatic, fire protection, and control and monitoring systems.
Built-In or Large, Substantial Affixed Equipment. A term used in connection with
affixed to, or installed in real property in such a manner that the installation cost, including special foundations or unique utilities service, or the facility restoration work required after its removal is substantial.
Commissioning The process of testing and accepting a system, line, building and other plant component. It is often the first (and sometimes last) opportunity for the "maintenance
department" to identify a design or build defect. Also see Building Commissioning.
Computerized Maintenance Management System (CMMS) A set of computer software modules and equipment databases containing facility data with the capability to process the data for facilities maintenance management functions. They provide historical data, report writing capabilities, job analysis, and more. The data describe equipment, parts, jobs, crafts, costs, step-by-step instructions, and other information involved in the maintenance effort. This information may be stored, viewed, analyzed, reproduced and updated with just a few keystrokes. The maintenance-related functions typically include –
a. Facility/Equipment Inventory b. Facility/Equipment History c. Work Input Control
d. Job Estimating
e. Work Scheduling and Tracking
f. Preventive and Predictive Maintenance g. Facility Inspection and Assessment h. Material Management
i. Utilities Management
Condition Assessment Condition assessment is the inspection and documentation of the material condition of facilities and equipment, as measured against the applicable maintenance standard. It provides the basis for long-range maintenance planning as well as annual work plans and budgets.
Condition Monitoring (also know as Predictive Maintenance) The continuous or periodic monitoring and diagnosis of systems and equipment in order to forecast failure. OR
Condition Monitoring: The continuous or periodic monitoring and diagnosis of systems and equipment in order to forecast failure. Condition Monitoring is a Time- or Cycle-Based Maintenance Action. Condition Monitoring is also known as Predictive Maintenance.
Condition-Based Maintenance Facility and equipment maintenance scheduled only when the condition of the facility or equipment requires it. CBM replaces maintenance scheduled at arbitrary time or usage intervals. It usually involves the application of advanced technology to detect and assess the actual condition
Corrective Maintenance See Repair.
Cost Effective An economic determination of the Maintenance Approach and entails
evaluation of maintenance costs, support costs, and consequences of failure. Also see Effective Maintenance Task.
Current Replacement Value (CRV) Approximate cost to replace an existing facility in its present form. NASA calculates CRV by escalating facility and collateral equipment acquisition cost, and any incremental book value changes of $1,000 or more to present-year dollars using the Engineering News Record (ENR) Building Cost Index (BCI). The NASA Real Property Data System program or NASA Headquarters-approved equivalent is used in performing the required calculations.
Critical Failure A failure involving a loss of function or secondary damage that could have a direct adverse effect on operating safety, on mission, or have significant economic impact.
Critical Failure Mode A failure mode that has significant mission, safety or maintenance effects that warrant the selection of maintenance tasks to prevent the critical failure mode from occurring.
Dominant Failure Mode A single failure mode that accounts for a significant portion of the failures of a complex item.
Effective Maintenance The application of the maintenance approach that will produce the required availability, at the lowest cost, without compromising human safety or health, the environment, or any other conditions the organization specifies.
Effective Maintenance Task A task that is characterized as performing its defined function with a high degree of success for a specified cost. A maintenance task must be both applicable and effective. The benefit of performing the task must be evaluated against the cost. Cost includes many elements; the cost of the task, repair costs when failure occurs, collateral damage caused by failure, and the cost of lost mission (such as production, space and flight operations, research, and administrative support) due to the loss of the facilities and collateral equipment function.
Facilities Maintenance The recurring day-to-day work required to preserve facilities
(buildings, structures, grounds, utility systems, and collateral equipment) in such a condition that they may be used for their designated purpose over an intended service life. It includes the cost of labor, materials, and parts. Maintenance minimizes or corrects wear and tear and thereby forestalls major repairs. Facilities maintenance includes Preventative Maintenance, Predicative Testing & Inspection, Grounds Care, Programmed Maintenance, Repair, Trouble Calls,
Replacement of Obsolete Items, and Service Request (Not a maintenance item but work
performed by maintenance organizations). Facilities Maintenance does not include new work or work on non-collateral equipment.
Failure A cessation of proper function or performance; inability to meet a standard;
nonperformance of what is requested or expected.
Failure Effect The consequences of failure.
Failure Mode: The manner of failure. For example, the motor stops is the failure, the reason the motor failed was the motor bearing seized which, is the failure mode.
Failure Modes and Effects Analysis (FMEA) Analysis used to determine what parts fail, why they usually fail, and what effect their failure has on the systems in total. An element of Reliability Centered Maintenance (RCM).
Failure Rate The number of failures divided by an interval such as time or cycles. The failure rate will change over time and can be greater than one (but will never be less than zero).
Fiscal Year In the Federal Government, it is the 12-month period from Oct. 1 of one calendar year through Sept. 30 of the following year.
Function Defined performance standard. Usually quantitative in nature (flow rate, cooling capacity, etc.).
Inspection A time- or cycle-based action performed to identify hidden failure or potential failure.
Infrared Thermography A predictive technique that uses infrared imaging to identify defects in electrical and electro-mechanical devices such as fuse boxes, circuit breakers, and switchgear.
It also can be used effectively in a non-predictive manner to detect thermal cavities and leaks in walls, ceilings, and rooftops, the correction of which can result in sizeable reductions in heating and air conditioning expenses. Thermal imaging is extremely sensitive, and since it evaluates the heat an object emits, emittance and reflective factors of the object and environment must be considered.
Key Performance Indicator (KPI) Critical few (key) indicators aligned throughout the organization that measure controllable performance and contribute towards achieving the organization objectives.
Life Cycle See System Life Cycle.
Maintainability The ability to retain or restore function within a specified period of time, when provided with an identified level of tools, training, and procedures. Maintainability factors include machine and systems access, visibility, simplicity, ease of monitoring or testing, special training requirements, special tools, and capability of local work force
Maintenance Action taken to retain function (i.e., prevent failure). Actions include Preventive Maintenance, Predictive Testing & Inspection, lubrication and minor repair (such as replacing belts and filters), and inspection for failure. Also see Preventive Maintenance and Predictive Testing & Inspection.
Maintenance Approach The plan to prevent failure and, when failure occurs, perform repair.
Mean Time Between Failure (MTBF) The reciprocal of the failure rate; the average time to fail. The MTBF is sometimes called the Mean Time To Fail (MTTF).
Mean Time To Fail (MTTF) See Mean Time Between Failure.
Mission Critical A building, area, or system that is critical to the Center/Facility mission or essential for Center of Excellence performance. Also see Mission Support and Center/Facility Support.
Mission Support A building, area, or system that provides support to the Center/Facility primary mission or Center of Excellence assignment. Also see Mission Critical and
Center/Facility Support.
Motor Circuit Analysis (MCA)— A predictive technique whereby the static characteristics (i.e.; impedance, capacitance to ground, inductance) of a motor or generator are measured as indicators of equipment condition.
Motor Current Spectrum Analysis (MCSA)— A predictive technique whereby motor current signatures provide information on the electro-mechanical condition of AC induction motors. It detects faults such as broken rotor bars, high resistance joints, and cracked rotor end rings by collecting motor current spectrums with clamp-on sensors and analyzing the data.
Non-collateral Equipment— All equipment other than collateral equipment. Such equipment, when acquired and used in a facility or a test apparatus, can be severed and removed after erection or installation without substantial loss of value or damage thereto or to the premises where installed. Noncollateral equipment imparts to the facility or test apparatus its particular character at the time, e.g., furniture in an office building, laboratory equipment in a laboratory, test equipment in a test stand, machine tools in a shop facility, computer in a computer facility, and it is not required to make the facility useful or operable as a structure or building. (See also Collateral Equipment.)
Pareto Analysis A problem solving tool that breaks data down into manageable groups and identifies the greatest opportunity for return on investment. The analysis is based on the Pareto Principle, also known as the 80:20 Rule. Simply stated, the principle says that 20% of a
population will cause 80% of the problems associated with the population.
Performance Standards— Those standards which an item is required to meet in order to maintain its required function. The performance standard defines functional failure for the item.
Potential Failure An identifiable condition that indicates a failure is imminent.
Predictive Testing & Inspection (PT&I) The use of advanced technology to assess machinery condition. The PT&I data obtained allows for planning and scheduling preventive maintenance or repairs in advance of failure. Also see Condition Monitoring and Condition-Based
Preventive Maintenance (1) Also called time-based maintenance or interval-based maintenance. PM is the planned, scheduled periodic inspection, adjustment, cleaning,
lubrication, parts replacement, and minor (no larger than Trouble Call scope) repair of equipment and systems for which a specific operator is not assigned. PM consists of many checkpoint activities on items that, if disabled, would interfere with an essential Center operation, endanger life or property, or involve high cost or long lead time for replacement. In a shift away from reactive maintenance, PM schedules periodic inspection and maintenance at predefined time or usage intervals in an attempt to reduce equipment failures. Depending on the intervals set, PM can result in a significant increase in inspection and routine maintenance; however, a weak or nonexistent PM program can result in safety and/or health risks to employees, much more emergency work, and costly repairs.
(2) Time- or cycle-based actions performed to prevent failure, monitor condition, or inspect for failure.
Predictive Maintenance See condition monitoring.
Proactive Maintenance The collection of efforts to identify, monitor and control future failure with an emphasis on the understanding and elimination of the cause of failure. Proactive maintenance activities include the development of design specifications to incorporated
maintenance lessons learned and to ensure future maintainability and supportability, the development of repair specifications to eliminate underlining causes of failure, and performing root cause failure analysis to understand why in-service systems failed.
Programmed Maintenance (PGM) Those maintenance tasks whose cycle exceeds one year, such as painting a building every fifth year. (This category is different from PM in that if a planned cycle is missed the original planned work still remains to be accomplished, whereas in PM only the next planned cycle is accomplished instead of doing the work twice, such as two lubrications, two adjustments, or two inspections.)
Reactive Maintenance See Repair.
Reliability The dependability constituent or dependability characteristic of design. From MIL-STC-721C: Reliability - (1) The duration or probability of failure-free performance under stated conditions. (2) The probability that an item can perform its intended function for a specified interval under stated conditions.
Reliability-Centered Maintenance (RCM) The process that is used to determine the most effective approach to maintenance. It involves identifying actions that, when taken, will reduce the probability of failure and which are the most cost effective. It seeks the optimal mix of Condition-Based Actions, other Time- or Cycle-Based actions, or Run-to-Failure approach.
Repair That facility work required to restore a facility or component thereof, including collateral equipment, to a condition substantially equivalent to its originally intended and
designed capacity, efficiency, or capability. It includes the substantially equivalent replacements
of utility systems and collateral equipment necessitated by incipient or actual breakdown. Also, restoration of function, usually after failure. Also see Planned Repair.
Root Cause Failure Analysis (RCFA) The process of exploring, in increasing detail, all possible causes related to a machine failure. Failure causes are grouped into general categories for further analysis. For example, causes can be related to machinery, people, methods,
materials, policies, environment, and measurement error.
Run-to-Failure A Maintenance Approach where no action is taken (Time- or Cycle-Based actions), following installation, to prevent failure. Candidate systems or machines for Run-to-Failure are usually low-cost, easily-repaired, and non-critical.
Time- or Cycle-Based Actions Maintenance activities performed from time-to-time that have proven to be effective in preventing failure. Items such as lubrication and restoration of wear fit this description. Other items that are Time- or Cycle-Based are inspection and condition
monitoring. Also see Predictive Testing and Inspection.
Vibration Analysis— The dominant technique used in predictive maintenance. Uses noise or vibration created by mechanical equipment to determine the equipment’s actual condition. Uses transducers to translate a vibration amplitude and frequency into electronic signals. When measurements of both amplitude and frequency are available, diagnostic methods can be used to determine both the magnitude of a problem and its probable cause. Vibration techniques most often used include broadband trending (looks at the overall machine condition), narrowband trending (looks at the condition of a specific component), and signature analysis (visual
comparison of current versus normal condition). Vibration analysis most often reveals problems in machines involving mechanical imbalance, electrical imbalance, misalignment, looseness, and degenerative problems.
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