Wrench Time
Wrench time is the percentage of observed or paid maintenance time spent directly performing hands-on maintenance work.
What this term means in maintenance
Wrench time is the percentage of observed or paid maintenance time spent directly performing hands-on maintenance work.
Wrench-time formula
Wrench time = Direct hands-on maintenance time ÷ Total observed maintenance time × 100
What counts as direct work
Direct work may include:
- Inspecting equipment
- Diagnosing faults
- Removing and installing components
- Adjusting, lubricating, or cleaning
- Testing and commissioning
- Performing checklist tasks
What may count as non-wrench time
Non-wrench time may include:
- Waiting for parts
- Travelling to the asset
- Obtaining permits or approvals
- Searching for tools
- Waiting for isolation
- Receiving instructions
- Administrative work
- Coordination with operations
Not every non-wrench activity is waste. Many activities are necessary for safe and controlled maintenance.
Practical example
A technician is observed for eight hours and spends four hours performing direct maintenance work.
Wrench time = 4 ÷ 8 × 100 = 50%
How the metric should be used
The purpose is to identify system obstacles such as poor planning, unavailable parts, excessive travel, or delayed access. It should not be used to pressure technicians into skipping safety, diagnosis, documentation, or coordination.
Common mistake
Short observation periods or unusual shutdown days can produce misleading results. Use a representative sample and explain the observation method.
Related concepts
Related maintenance terms
Keep exploring connected CMMS, reliability, and maintenance planning terms.
Maintenance Backlog
Maintenance backlog is approved maintenance work that has not yet been completed, commonly measured by job count, estimated labor hours, age, risk, or weeks of available labor capacity.
Work Order
A work order is an authorized record that defines maintenance work to be performed, including the asset, priority, scope, assignee, instructions, labor, parts, status, and completion evidence.
Maintenance Schedule Compliance
Maintenance schedule compliance is the percentage of maintenance tasks scheduled for a defined period that were completed within the agreed schedule window.
Glossary FAQs
- What is included in wrench time?
It normally includes direct inspection, diagnosis, repair, adjustment, servicing, testing, and other hands-on maintenance activities.
- Is all non-wrench time waste?
No. Safety permits, isolation, diagnosis, coordination, travel, and documentation may be necessary activities.
- How should wrench time be used?
Use it to identify system delays and planning obstacles, not to pressure technicians into skipping safe and necessary work.