Wrench Time

Table of Contents

Wrench time is a key performance metric in maintenance management. Tracking wrench time allows organizations to identify strategies to optimize maintenance processes, reduce downtime, and increase equipment reliability. 

What is Wrench Time?

Wrench time, also called tool time, is defined as the amount of time that maintenance technicians or personnel spend working on a machine or equipment while using tools like wrenches (hence the name). A wrench time in hours corresponds to one maintenance activity or job and can be reported as a weekly, monthly, or quarterly average.

Internal vs. External Wrench Time

Internal wrench time refers to the time spent by in-house technicians on maintenance activities. External wrench time, on the other hand, refers to the amount of time spent on maintenance activities by third-party contractors or outsourced service providers.

Wrench Time Types and Examples

Below are the different maintenance task types and typical examples of wrench time: 

Planned Tasks

Every maintenance program consists of tasks scheduled for a machine or asset. A machine say, a hydraulic press, can have scheduled preventive maintenance (PM) tasks such as lubricating, inspecting for signs of wear and tear, replacing worn-out parts, etc. If the technician performs these PM tasks in 3 hours while actively using tools, then the wrench time for the scheduled PM is 3 hours. These 3 hours must not include the time spent in the preparation of parts, lubricants, and tools.

Unplanned Tasks

When a piece of equipment or machinery breaks down unexpectedly, maintenance may assign an unplanned task to restore the asset experiencing failure. For example, if a mixer stops working, a maintenance technician would be tasked to diagnose the failure. Using tools, the technician can spend an hour inspecting electrical connections, control panels, or faulty parts. Hence, the wrench time for this unplanned task is 1 hour. 

Repair Work

Repair work, which can be planned or unplanned, includes any task that restores normal functions to malfunctioning assets. For example, if the trouble is a faulty motor, the repair wrench time includes dismantling the faulty motor, replacement with a new motor, and lastly, testing whether the new motor is working properly.

Administrative Activities

Administrative activities include completing checklists, creating work schedules, creating reports, etc. After repair work, a technician can spend 30 minutes accomplishing work order forms, updating inventory data, recording repair details and information, and filing all relevant forms and paperwork. In this example, the documentation wrench time is 0.5 hours.

Measuring Wrench Time

There are four general ways to measure wrench time:

Statistical Method

This method might be the most accurate way of measuring wrench time. This method uses large observational data and wide periods, ensuring an equal chance of observation for all data sources.

Day In Life Of (DILO)

This method selects a random technician to be observed on a random day. Although easier to use than the statistical method, the DILO may not be as accurate a representation of the actual wrench times in a facility.

Work Sampling

This method observes random technicians at set intervals within a workday. This method is similar to DILO in that it has a shorter range of observation. 


This method is where technicians report the details of their work schedules including the data for their wrench times. If not done right, this method can result in inaccuracy from intentional or unintentional errors in recording.

Interpreting Wrench Time

Once you’ve collected wrench times for specific tasks and assets, what do you do? The following are the steps to working with wrench time data and using it to achieve your bottom line.

  1. Review all wrench time trends over a specific period, monthly and quarterly are ideal. Compare the wrench time of technicians, individually and collectively, and compare them to identify changes or patterns.
  2. Break down wrench times by different types of maintenance tasks: planned, unplanned, repair, or administrative. Analyze the distribution of wrench times to understand what tasks take up most of your total wrench time.
  3. Compare the planned vs. unplanned wrench times. The higher the unplanned wrench times the lower the reliability of assets.
  4. Evaluate diagnostic and repair wrench times. Identify instances when diagnostic and repair times have long durations and investigate the situations for areas of improvement.
  5. Identify bottlenecks or delays that contribute to prolonged wrench times. The most common reasons for these delays can be long waits for spare parts, inefficient work procedures, and unavailable tools, technicians, and other resources.
  6. Compare wrench times with existing standards. Research industry processes similar to your organization and compare the standard wrench times to your results. From here, you can set your specific standards based on your actual results.
  7. Keep gathering and analyzing wrench time data for continuous improvements. Revise existing standards to fit the changing asset requirements, operation conditions, and company goals.

Wrench Time with Redlist

With a powerful and user-friendly CMMS (Computerized Maintenance Management System) like Redlist, your wrench time data and analysis can experience the following benefits:

  • Paperless forms and digital recording reduce administrative wrench time.
  • Cloud-based data improves information sharing and minimizes delays due to slow or inaccurate decision-making.
  • Improved inventory management system minimizes inventory-related delays.
  • Real-time scheduling and tracking of PM tasks makes it easy to implement PM strategies and minimize unplanned wrench times.
  • Powerful computing functions spot trends and generate insightful reports for identifying areas of improvement.
  • Mobile accessibility lets technicians stay productive and accomplish more tasks from any location.

Experience these benefits and more. Schedule your free Redlist demo today!

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