Glossary of terms
Representative best practice. A typical value reported by outstanding plants. Not necessarily the “best of the best” or an absolute target.
Representative range. Range of values typically reported by plants. Levels outside the range may represent particularly outstanding or weak performance.
ERV. Estimated replacement value. Usually the total value of the plant as used for insurance purposes.
Process industries. Industries that predominantly use batch or continuous processing to produce a bulk product (e.g., foods and chemicals).
Discrete industries. Industries that predominantly manufacture discrete parts, components, or units of equipment.
Total sales. Dollar value of a plant’s annual product output.
Technician. Any maintenance worker performing direct maintenance labor. Includes mechanics, electricians, millwrights, etc. Often called “direct maintenance personnel,” “hourly personnel,” or simply “mechanics.”
Maintenance cost/ERV. Ratio of total annual cost of maintenance to plant’s estimated replacement value. A measure of dollars required to maintain value of the plant. Also a general indicator of maintenance cost effectiveness. A downward trend without real maintenance improvements can indicate milking of assets.
Total maintenance cost/total sales. Ratio of total annual cost of maintenance to plant’s output. Indicates portion of revenues used to maintain assets. May also indicate maintenance cost effectiveness.
Maintenance labor cost/total sales. Ratio of total maintenance labor compensation to plant’s output. Facilitates comparison and trending of the labor component of total maintenance costs.
Maintenance materials cost/total sales. Ratio of total annual cost of maintenance parts, materials, and supplies to plant’s output. Facilitates comparison and trending of the materials component of total maintenance costs.
ERV ($millions)/technician. Ratio of estimated replacement value, expressed in millions of dollars, per maintenance technician. Indicator of direct maintenance worker productivity. An upward trend can indicate either improvements in maintenance practices or a need for more personnel.
ERV ($millions)/maintenance and reliability engineer. Ratio of estimated replacement value, expressed in millions of dollars, per maintenance staff engineer. Indicator of maintenance supervisory and engineering productivity.
Work-order coverage. Percentage of maintenance manhours documented by work orders. A measure of recordkeeping discipline. A high percentage indicates that work-order data can be used to determine service levels and manpower requirements.
Schedule compliance (overall). Percentage of maintenance manhours worked as scheduled. An indicator of overall maintenance management effectiveness, including planning, estimating, scheduling, materials availability and delivery, tools management, etc.
Schedule compliance, preventive maintenance. Percentage of preventive maintenance manhours worked as scheduled. An indicator of preventive maintenance management effectiveness.
Schedule compliance, planned repairs. Percentage of planned repairs manhours worked as scheduled. An indicator of the effectiveness of planned repairs management.
Planned work (overall). Percentage of the maintenance workload that is known and planned in advance, including job planning, materials management, and resource scheduling. An indicator of overall maintenance management effectiveness. A high percentage is desirable.
Overall equipment effectiveness. Percent of actual operations against perfect production rates assuming no scheduled or unscheduled downtime, no defective product, and no reduced production rates.
Uptime. Ratio of actual production hours to scheduled production hours. A measure of unscheduled interruptions to production. Indicator of effectiveness of preventive and predictive maintenance in combination with other factors.
Availability. A ratio of the time equipment is actually available to the total scheduled equipment time. The availability ratio is computed by adding the scheduled running time to the scheduled idle time and subtracting the unscheduled downtime, then dividing that value by the sum of the scheduled running time plus the scheduled downtime plus the scheduled idle time.
Planned and predictive maintenance by operators. Amount of maintenance performed by equipment operators.
Maintenance labor cost/total maintenance cost. Percent of total maintenance cost attributable to direct labor. May be used as an indicator of manpower planning effectiveness.
Contractor cost/total maintenance cost. Percent of total maintenance cost attributable to outside contract work. Heavily dependent on strategy.
OSHA injuries/200,000 manhours. (Sometimes stated as OSHA injuries per 100 employees.) The standard indicator of safety program effectiveness.
Technicians/support person. Ratio of direct workers to support personnel, such as planners, clerks, storekeepers, etc. Indicator of manpower planning effectiveness.
Technicians/planner. Ratio of direct maintenance workers to personnel involved in maintenance planning (including partial headcounts for people who plan part time). An indicator of planning effectiveness.
Technicians/total workforce. Ratio of direct maintenance workers to total plant employment. Useful in specific comparisons between similar plants and as a trend indicator over time.
Maintenance craft classifications. Number of formally classified maintenance crafts represented in the plant. Heavily dependent on labor practices and plant strategy.
Preventive maintenance and predictive maintenance manhours/total maintenance manhours. An indicator of effectiveness of plant’s proactive maintenance programs to ensure equipment reliability.
Emergency manhours/total maintenance manhours. Ratio of manhours to complete emergency work to the total maintenance manhours. Indicator of maintenance planning, control, and problem prevention.
“Wrench time”/Total maintenance manhours. Percentage of time that direct maintenance workers are advancing completion of a maintenance task. Includes time spent using tools; excludes idle time, planning, traveling, transporting, securing information, etc. Indicator of overall maintenance management effectiveness.
Stores value/ERV. Ratio of the value of parts and materials in maintenance stores to the plant estimated replacement value. A measure of working capital invested in local stores. Strongly dependent on maintenance materials management strategy.
Stores turnover. Ratio of annual stores disbursements to inventory value. Strongly dependent on stocking strategy.
Stores inventory accuracy. Ratio of actual inventory to “paper” inventory. Indicator of stores recordkeeping effectiveness.
Stores disbursements/stores personnel. Ratio of dollar value of disbursements to number of storekeepers. Indicator of “productivity” of stores operations and personnel.