Wrench time, also called “tool time,” is the amount of time maintenance technicians spend actively working on equipment. This work may include making repairs, carrying out inspections or completing regular maintenance tasks. Wrench time does not include time spent waiting for instructions or parts, preparing paperwork or attending meetings.
As a rule, higher wrench time means greater productivity. Average wrench time sits between 25% and 35% of a worker’s shift. Wrench time may be measured per job, or calculated as a weekly, monthly or quarterly average.
Wrench time plays a vital role in maintenance efficiency. To fully understand its impact, it’s important to know how to calculate it, recognize the common factors that reduce it and identify practical steps to improve your team’s average.
Why is wrench time important?
Wrench time plays a key role in production plant performance. Consider a critical piece of machinery. If it fails, your business loses money until it’s back up and running. Higher wrench time means more time spent directly fixing the problem, in turn reducing your total downtime. Low wrench time not only slows down the process but often means more technicians are working on the problem over multiple days, which can lead to redundant efforts and miscommunications.
Measuring wrench time provides front-line visibility into maintenance planning and repair efforts. The more accurate your reporting, the better equipped you are to identify possible issues and make necessary changes. Key metrics tied to wrench time include:
- Process efficiency — Higher wrench time typically indicates greater process efficiency. This is because more wrench time allows staff to both fix outstanding issues and make improvements that streamline key processes.
- Machine uptime — More wrench time means improved machine uptime. Wrench time uses for proactive or preventive maintenance can reduce the risk of unexpected production line failures leading to costly downtime.
- Labor costs — Low wrench time can lead to higher labor costs. Consider a technician who spends most of the day attending meetings and completing paperwork. The result is minimal wrench time, which leaves maintenance tasks incomplete and requires additional work from other technicians or on subsequent shifts, leading to higher overall labor costs.
- Capacity planning — Accurate reporting of wrench time data helps companies estimate the workforce capacity needed to complete preventive and predictive maintenance tasks. If wrench time is higher than average but machine operations remain inconsistent, more staff may be needed.
Wrench time calculation formula
Wrench time is typically calculated as a percentage. It is measured by dividing the time spent on actual maintenance tasks by the total amount of work time available, then multiplying this number by 100.
Formula
Wrench time = (Time spent on maintenance tasks / Total work time available) x 100.
Definitions
Time spent on maintenance tasks refers to hands-on tools time, which includes physically carrying out repairs, performing inspections or adjusting calibrations.
Total work time available is the length of a technician’s shift minus any breaks, meetings or other scheduled non-maintenance activities.
Example
A technician is scheduled for an 8-hour shift. Breaks and meetings take 1 hour total, leaving 7 hours of total work time available. Of that, 2.5 hours are spent completing hands-on maintenance activities, so:
Wrench time = (2.5 hours / 7 hours) x 100 = 35.7%.
As noted above, the average industrial wrench time is 25% to 35%. Top-performing organizations, meanwhile, often aim for 50% or higher wrench time, as noted in “Rules of Thumb for Maintenance and Reliability Engineers” (R. Keith Mobley and Ricky Smith, 2007). While many companies can’t reach this mark, even small improvements in wrench time can have big benefits. Consider the example above. Even an extra half an hour spent on maintenance raises wrench time to 42.9%.
Measuring wrench time requires consistent and accurate maintenance activity tracking. Common tracking methods include wrench time studies, digital work order reports, and computerized maintenance management systems (CMMS). Techniques like work sampling can provide helpful observational data to support wrench time analysis and improvement.
Common factors that reduce wrench time
While production targets, machine complexity and cycle times vary across industries, several common factors reduce wrench time, such as:
- Operational delays: Waiting on parts, tools or approvals to start work.
- Poor work order management: Unclear or missing instructions or poorly scoped jobs.
- Travel and walk time: Time spent moving between jobs or walking to find needed tools.
- Equipment accessibility: Complex layouts that make machines hard to access and repair.
- Reporting and documentation requirements: Excessive paperwork or poor use of CMMS systems.
- Lack of coordination across teams: Poor communication across maintenance teams, planners and production staff that results in duplicated or missed work.
It’s worth noting that there’s no such thing as “perfect” wrench time. No matter how skilled your staff or how available your parts, there will always be prerequisite tasks and post-maintenance reports reduce overall wrench time.
As a result, your goal isn’t to eliminate all sources of non-wrench time, but instead focus on minimizing unnecessary delays and removing roadblocks that get in the way of hands-on efforts.
How to improve wrench time in industrial maintenance
A combination of technology, training and strategic process changes can improve wrench time. Effective approaches include:
- Better planning and scheduling: Using proactive maintenance scheduling tools can help streamline job scoping, labor assignments and parts staging.
- Parts kitting and pre-staging: Preparing all tools and parts in advance can reduce prep time before work begins.
- Digital work orders: Deploying mobile CMMS platforms lets staff easily enter and record maintenance data.
- Asset accessibility improvements: Optimizing layouts can minimize travel time and make it easier for technicians to work.
- Cross-training staff: Training staff in multiple skill sets can increase overall wrench time.
- Continuous improvement programs: Ongoing efforts such as lean manufacturing implementation, maintenance kaizen events and root cause analysis sessions can help pinpoint systemic barriers to improved wrench time.
How outsourced maintenance supports wrench time improvement
Outsourced maintenance services from ATS can help improve overall wrench time and increase operational efficiency. Our approach to improved maintenance operations is built on four key components:
- Proven maintenance strategies: ATS uses best-in-class maintenance strategies including planning, scheduling and predictive maintenance solutions to help identify and resolve bottlenecks.
- Dedicated on-site teams: Full-time, highly-skilled ATS maintenance technicians use structured processes to maximize active maintenance time. For example, our teams can suggest better ways of managing spare parts inventory to reduce possible delays.
- Data-driven improvements: Leveraging a combination of CMMS, real-time analytics and machine health monitoring tools helps our experts identify and remove inefficiencies.
- Flexible solutions: Whatever your needs, ATS has you covered. Need to supplement your in-house team? No problem. Looking for end-to-end plant maintenance management? Absolutely. When it comes to improved wrench time and workforce optimization, we’re here to help.
Ready to improve wrench time and enhance productivity? Get started with ATS. Let’s talk.
References
Smith, Ricky, and R. Keith Mobley. Rules of Thumb for Maintenance and Reliability Engineers. Butterworth-Heinemann, 2007.
