Ask most maintenance managers how productive their technicians are, and they will say 70% or 80%. Then you do a wrench time study and find out the real number is 28%. That gap between perception and reality is why wrench time matters. It shows you where your maintenance hours are actually going, and the answer is rarely what people expect.
Wrench time (also called tool time or direct work time) measures the percentage of a maintenance technician's shift spent physically working on equipment with tools in hand. It does not include travel time, waiting for parts, reading work orders, attending meetings, taking breaks, looking for tools, getting permits, or any other activity that is not hands-on repair, inspection, or installation work.
The concept is simple: if a technician works an 8-hour shift, how many of those 480 minutes are spent actually turning wrenches, connecting wires, replacing bearings, aligning shafts, or calibrating instruments?
The industry average across manufacturing plants worldwide is 25-35%. That means a typical maintenance technician spends only 2 to 2.8 hours of an 8-hour shift doing actual maintenance work. The rest, 5 to 6 hours, goes to everything else.
This is not because technicians are lazy. It is because the systems around them are inefficient. They walk to a job, find the work order is missing information, walk to the storeroom, wait in line for parts, discover the parts are not in stock, go find a supervisor, get reassigned to a different job, walk to the new location, realize they need a different tool, walk back to the shop. The problem is organizational, not individual.
What Wrench Time Actually Measures
Wrench time is a measure of how well your maintenance planning and scheduling system supports your technicians. A high wrench time means your systems are effective: technicians get clear work instructions, the right parts are staged, tools are available, permits are ready, and the equipment is accessible when they arrive. A low wrench time means your systems are failing: technicians spend more time dealing with obstacles than doing work.
Here is how wrench time breaks down in a typical plant with no formal planning and scheduling:
Let us break down each category:
Direct work (wrench time): 25-35%
Hands on the equipment. Replacing a motor. Rebuilding a valve. Aligning a coupling. Calibrating a sensor. If the technician's tools are touching the equipment and they are performing the actual maintenance task, it counts as wrench time.
Travel: 12-18%
Walking or driving between the shop, the storeroom, and the job site. In large plants (refineries, steel mills, paper mills), travel can consume 15-20% of a shift. A technician making 4-5 trips per day between the workshop and different job locations can easily walk 5-8 kilometers in a shift.
Waiting for parts: 10-15%
Standing in line at the storeroom. Waiting for a part that was supposed to be there but is not. Waiting for a part to be delivered from an outside supplier. In plants without kitting (pre-staging parts for planned jobs), this is one of the biggest time wasters.
Getting instructions and information: 8-12%
Reading work orders that lack detail. Finding the right manual or drawing. Calling engineering to clarify specifications. Asking another technician how to do something. Searching for repair history on a machine. This category is directly related to the quality of your work planning and your knowledge management systems.
Permits and safety preparation: 5-10%
Lockout/tagout procedures, confined space permits, hot work permits, waiting for process to shut down and isolate. This time is necessary for safety and cannot be eliminated, but it can be reduced through better pre-job planning. Having permits ready before the technician arrives at the job site saves significant time.
Breaks: 8-12%
Scheduled lunch and rest breaks. These are legitimate and expected. However, some studies show that actual break time exceeds scheduled break time by 15-25 minutes per shift on average, often because technicians are waiting for something anyway and extend their break rather than standing idle.
Admin and paperwork: 5-8%
Filling out work order completions, updating the CMMS, writing shift reports, attending start-of-shift meetings. This is necessary work, but overly complicated CMMS interfaces and excessive documentation requirements inflate it.
Other delays: 5-8%
Waiting for the equipment to be released by production. Waiting for a crane or forklift. Waiting for another trade (electrician waiting for the pipe fitter to finish). Idle time between jobs. Personal time beyond scheduled breaks.
How to Conduct a Wrench Time Study
A wrench time study uses a technique called work sampling (sometimes called a delay survey). An observer records what technicians are doing at random intervals throughout the day. You do not follow one technician continuously. Instead, you observe many technicians at random moments and categorize each observation.
Step 1: Define the categories
Before you start, define 6-10 activity categories. Keep it simple. The categories listed above (direct work, travel, waiting for parts, getting instructions, permits, breaks, admin, other delays) are a good starting point. Every observation must fit into one category.
Step 2: Set up the observation schedule
You need at least 300-400 observations for statistically reliable results. If you have 15 maintenance technicians and observe each one at random 3-4 times per day over 5 days, you will get approximately 300 observations. Use a random time generator to set observation times. Do not observe at the same time every day, or you will bias the results toward whatever happens at those times.
Step 3: Train the observers
The observer walks through the maintenance area at the scheduled times and records what each visible technician is doing at the moment of observation. They do not ask the technician what they are doing. They observe and categorize. This takes practice. Is the technician reading a drawing (getting instructions) or checking a specification while actively working on equipment (direct work)? You need clear rules.
Step 4: Collect the data
Record every observation on a simple data sheet or tablet app. Note the time, the technician (optional, for deeper analysis), and the activity category. Do not tell technicians exactly when observations will happen. If they know they are being watched at 10:15 AM, they will be at the machine at 10:15 AM. General awareness is fine ("we are doing a maintenance productivity study this week"), but specific timing should not be disclosed.
Step 5: Analyze and present results
Calculate the percentage for each category. Present the results as a pie chart or bar chart. The total should add to 100%. Compare against industry benchmarks:
| Wrench Time Level | Percentage | What It Means |
|---|---|---|
| Poor | Below 25% | No planning and scheduling, mostly reactive |
| Typical | 25-35% | Some planning, inconsistent execution |
| Good | 35-45% | Formal planning and scheduling in place, parts kitting used |
| Excellent | 45-55% | Mature planning, excellent storeroom, strong scheduling |
| World-class | 55-65% | Best practices in all areas, minimal delays |
Nobody reaches 100% wrench time. There will always be some travel, breaks, and coordination. The realistic target for a well-run industrial plant is 50-55%. Getting from 28% to 50% effectively doubles your maintenance capacity without hiring a single additional technician.
The Math That Gets Management's Attention
Here is why wrench time matters financially. Suppose you have 20 maintenance technicians, each earning an average fully loaded cost of $85,000 per year (salary, benefits, overhead). Your total maintenance labor budget is $1.7 million per year.
At 28% wrench time, you are getting 28% of $1.7 million = $476,000 worth of actual maintenance work. The remaining $1.224 million is paying for travel, waiting, searching, and delays.
If you improve wrench time from 28% to 45%, you get 45% of $1.7 million = $765,000 worth of actual maintenance work. That is a 61% increase in effective maintenance output for zero additional labor cost.
Put another way: improving wrench time from 28% to 45% gives you the equivalent output of 7 additional technicians without hiring anyone. At $85,000 per person, that is $595,000 per year in equivalent capacity.
8 Ways to Improve Wrench Time
Each of these addresses a specific source of wasted time identified in wrench time studies.
1. Implement formal job planning
A dedicated maintenance planner reviews each work order before it is scheduled. They identify the required parts, tools, skills, permits, and procedures. They write a job plan that tells the technician exactly what to do, what they need, and how long it should take. Studies by Doc Palmer (author of Maintenance Planning and Scheduling Handbook) show that one planner supporting 20-30 technicians increases wrench time by 10-15 percentage points.
Good job planning means the technician arrives at the job with everything they need. No hunting for parts. No searching for drawings. No guessing at torque specs.
2. Kit parts before the job starts
For every planned job, stage all required parts in a kit with the work order number on it. When the technician picks up the work order, they pick up the parts kit at the same time. This eliminates storeroom trips and waiting in line. Plants that implement kitting typically see a 5-8% improvement in wrench time.
3. Reduce travel distance
Locate satellite tool cribs and parts staging areas near the major maintenance work areas instead of requiring all technicians to walk to one central storeroom. In large facilities, consider mobile tool carts positioned at common work zones. If your plant covers 50 acres and all spare parts are in one building at the north end, technicians working at the south end lose 30-45 minutes per round trip just walking.
4. Pre-stage permits and safety prep
Have operations prepare lockout/tagout permits and equipment isolation before the scheduled maintenance window. When the technician arrives, the equipment is already locked out and ready to work on. Do not make the technician wait for operations to finish their part of the preparation.
5. Improve work order quality
A work order that says "pump is leaking, please fix" forces the technician to investigate, diagnose, find parts, and plan the job on the fly. A work order that says "replace mechanical seal on pump P-2104, kit #4521 staged in area B storeroom, estimated 2.5 hours, see job plan JP-2104-003 for procedure" lets the technician go straight to productive work. The quality of work orders directly correlates with wrench time. Structured breakdown response processes help improve initial work order quality.
6. Build and maintain a repair knowledge base
When a technician has to figure out how to repair a machine from scratch, it takes much longer than when they can reference a documented procedure from the last time the same repair was done. A searchable knowledge base of repair procedures, troubleshooting guides, and video SOPs reduces the time spent getting instructions. Dovient's platform is designed specifically for this: capturing repair knowledge and making it accessible at the point of work.
7. Schedule work properly
Scheduling is different from planning. Planning answers "what does this job need?" Scheduling answers "when should this job happen and who should do it?" Good scheduling fills the available maintenance hours with planned work, assigns jobs to technicians with the right skills, and sequences jobs to minimize travel and waiting. Without scheduling, technicians self-assign work, which leads to inefficient routing and skill mismatches.
8. Use weekly schedule compliance as a feedback loop
Track what percentage of the weekly schedule actually gets completed. If schedule compliance is below 80%, find out why. Common reasons: emergency work displacing planned work, equipment not released by operations, parts not available despite being planned. Address the root causes. High schedule compliance correlates directly with high wrench time because it means the planning and scheduling system is working. This also connects to PM compliance tracking.
Before and After: What Improvement Looks Like
The table below shows the typical improvement from implementing formal planning and scheduling. Notice that breaks stay the same (they should) and permits decrease only slightly (safety time is not the target). The big wins come from parts waiting, travel, and getting instructions.
| Activity Category | Before P&S | After P&S | Change |
|---|---|---|---|
| Direct work (wrench time) | 28% | 48% | +20 pts |
| Travel | 16% | 10% | -6 pts |
| Waiting for parts | 14% | 5% | -9 pts |
| Getting instructions | 12% | 4% | -8 pts |
| Permits and safety | 8% | 6% | -2 pts |
| Breaks | 10% | 10% | No change |
| Admin and paperwork | 7% | 5% | -2 pts |
| Other delays | 5% | 12% | +7 pts* |
*The "other delays" category sometimes increases after planning and scheduling improvements because the big delay categories shrink and uncover smaller, previously hidden inefficiencies. It also includes legitimate idle time when scheduled work is complete and no additional work is available in the area.
Common Objections to Wrench Time Studies
When you propose a wrench time study, expect pushback. Here are the common objections and how to handle them:
"You are spying on us." Be transparent about the purpose. The study measures the system, not the people. Frame it as: "We want to find out what obstacles are making your jobs harder so we can remove them." Most technicians, once they understand the purpose, welcome it because they are frustrated by the same delays the study reveals.
"Our situation is different." Every plant says this. And every plant that does a wrench time study finds results between 25-35%. It does not matter if you are a refinery, a paper mill, or an auto parts plant. The delays are universal because the root causes (poor planning, parts availability, information access) are universal.
"The results will be used against us at budget time." Address this directly with management before the study. Wrench time improvement is about working smarter, not cutting headcount. The goal is to get more maintenance work done with existing staff, which reduces backlog, improves equipment reliability, and reduces overtime.
"We do not have time to do a study." A wrench time study requires one observer for one week. The investment is approximately 40 person-hours. The potential return (equivalent of multiple additional technicians at zero cost) justifies the investment many times over.
Wrench Time and Other Maintenance Metrics
Wrench time connects to several other key maintenance metrics:
- OEE: Higher wrench time means more maintenance gets done, which means fewer breakdowns, which improves Availability. It also means PMs get completed on schedule, which reduces quality-related failures.
- MTTR: When a breakdown occurs, the repair time includes wrench time and non-wrench time. Improving wrench time (by having parts ready, information available, and equipment accessible) directly reduces MTTR.
- PM compliance: If your technicians can only do productive work for 2.5 hours of an 8-hour shift, completing the PM schedule is nearly impossible. Higher wrench time means more capacity to complete planned PMs.
- Maintenance backlog: The primary way to reduce backlog is to increase the amount of work your team completes each week. That means either hiring more people or improving wrench time. Wrench time improvement is usually the better option.
Where Dovient Fits
Two of the biggest drags on wrench time are "getting instructions" and "searching for information." When a technician arrives at a job and does not know the repair history, the correct procedure, or the parts required, they lose time figuring it out.
Dovient directly reduces that lost time by:
- Putting repair knowledge at the point of work. Technicians search for a machine or symptom on a tablet and get the repair history, recommended procedures, and video SOPs immediately. No walking back to the office. No digging through filing cabinets.
- Faster diagnosis with AI-powered diagnostics. When a technician encounters an unfamiliar problem, Dovient's AI matches symptoms against your plant's historical repair data and suggests the most likely cause and fix. This reduces the "getting instructions" time from 12% to well below 5%.
- Preserving tribal knowledge so it does not leave when experienced people retire. The knowledge that speeds up repair work is available to everyone, not locked in one person's memory.
If your wrench time study reveals that technicians are spending significant time searching for information and repair procedures, schedule a conversation with our team to see how Dovient can help.