The equipment maintenance log: what an entry should hold, codes that can be counted, what the history is used for, and a free template
What an equipment maintenance log should record, why the condition as found matters more than the work done, failure mechanism, cause and action codes simplified from ISO 14224, what the history is used for, and keeping it in a CMMS or a spreadsheet. With a drawing of one asset's history and a free Excel maintenance log template.
Key takeaways
- An equipment maintenance log is the history of every piece of work done on each asset: what was found, what was done, the parts, the hours and the downtime. It is the record every reliability decision is made from.
- The most valuable sentence in an entry is what was found. What was done is in the work order. The condition as found is what tells the next person, and the analyst, how the asset is failing.
- Every entry belongs to an equipment tag, the same tag as the CMMS and the drawings, so the history follows the position in the plant.
- Short code lists for the failure mechanism, cause and action, simplified from ISO 14224, turn free text into something that can be counted across assets.
- On most sites the log is the CMMS work order history. A spreadsheet log is a sound start for a small operation or a single critical asset, and the free template here follows the same structure.
A conveyor drive fails on a Sunday afternoon and the reliability engineer is asked on Monday whether it was bad luck. The work order history has eleven entries for the drive over two years. Nine say "serviced" or "repaired". None says what was found. The engineer can count the jobs but cannot say whether the drive has been failing the same way for two years or whether this was new.
This guide covers the equipment maintenance log: what an entry should hold, the code lists that make entries countable, how the history is used, and how to keep it useful whether it lives in a CMMS or a spreadsheet. A free Excel template follows the same structure. It sits beside the guides to work order management and the ISO 14224 asset hierarchy, which sets the structure the history hangs on.
Free download
Equipment maintenance log template
A maintenance log with one row per piece of work, drop-down codes for the work type, failure mechanism, cause and action, downtime worked out from start and end, and a summary of breakdowns, downtime and labour for any equipment tag.
One asset's history
Read together, the entries on one asset tell a story that no single work order does. On the drive in the drawing, an oil sample showed wear metals and water rising, a seal leak followed, the seal and sleeve were replaced, and six weeks later the coupling failed with the alignment found out. Each entry is ordinary. The pattern, from contamination to wear to an installation fault after a repair, is what the reliability engineer needs, and it is only visible because each entry says what was found and carries its codes.
What was done is in the work order. What was found is the history.
What a useful entry holds
A useful entry answers the questions the next person and the analyst will ask, without anyone having to remember the job. The tag ties it to the position in the plant. The work type separates planned from unplanned. What was found, the codes and the readings make it analysable.
| Part | Why it matters | Example |
|---|---|---|
| The equipment, by tag | So the history attaches to the position in the plant, not a description that varies | CV-201-DR, not "conveyor 201 gearbox" |
| The work type | So preventive, corrective and breakdown work can be counted apart | Breakdown |
| What was found | The condition as found, the most valuable sentence in the record | Coupling insert failed, drive tripped on overload |
| What was done | The action, the parts and the hours | Insert replaced, alignment corrected, 6 hours |
| Mechanism, cause and action codes | So failures can be grouped and counted across assets | Misalignment, installation, replaced |
| Downtime | When the equipment stopped and restarted, if it did | 14:10 to 17:40 |
| Readings | Any measurement taken, with its unit, so it can be trended | Offset 0.4 mm before, 0.05 mm after |
Codes that can be counted
Free text is readable but cannot be counted. Short code lists for the failure mechanism, the cause and the action turn a year of entries into a table of how equipment fails and why. ISO 14224 gives standard lists for each, and a simplified version, a dozen or so mechanisms and causes, is enough for most sites. Unknown is an acceptable cause. A guessed one is worse than none, because it sends the analysis the wrong way.
The lists have to stay stable once data is recorded against them, or the history splits into before and after. They are best set up with the CMMS master data and changed through the same control as any other master data.
What the history is used for
A maintenance history is collected once and used for many decisions. Each use depends on a part of the entry being filled in properly, which is the argument to make to the crews who fill it in: the record they write is what decides which jobs get engineering attention and which parts are kept on the shelf.
| Use | What it answers | What it needs from the log |
|---|---|---|
| Bad actor lists | Which assets fail most often and cost the most downtime | Counts of breakdowns and hours by equipment |
| MTBF and MTTR | How often an asset fails and how long it takes to restore | Breakdown dates and downtime per asset |
| Strategy review | Whether each maintenance task is preventing the failures it was meant to | Mechanism and cause on corrective work, against the tasks in the plan |
| Root cause analysis | The history before a significant failure | What was found and done on the asset over the previous months |
| Spares setting | How often parts are used | Parts used per asset and per period |
| Condition trends | How a measured condition is changing | Readings recorded as values with units |
CMMS or spreadsheet
On a site with a CMMS, the maintenance log is the work order history, and the job is making the close out fields good rather than keeping a second log. That means completion comments that say what was found, failure codes required on corrective and breakdown work, and supervisors who check them before the work order closes, which the work order management guide covers.
Without a CMMS, or for a single critical asset, a spreadsheet log is a sound start, provided it uses the same tags, the same structure and the same codes a CMMS would, so it can be loaded into one later. The template offered here is built that way, with a summary that counts breakdowns, downtime and labour per asset, the inputs to the MTBF and MTTR calculator.
Where maintenance logs go wrong
- Entries that say "serviced" or "repaired" and nothing about the condition found.
- Equipment described in words instead of by tag, so one asset's history is spread across several names.
- Failure codes left blank, or set to Other, so nothing can be counted.
- Causes guessed rather than recorded as unknown.
- Readings written in comments rather than as values with units, so they cannot be trended.
- A second log kept in a spreadsheet alongside the CMMS, so neither is complete.
- History lost when equipment is swapped, because the work was recorded against the machine rather than the position.
Common questions
What is an equipment maintenance log?
An equipment maintenance log is the record of all maintenance done on a piece of equipment over its life: the date, the work type, the work order, what was found, what was done, the parts used, the labour, any downtime and any readings taken. On most industrial sites it is the work order history in the CMMS. Smaller operations keep it in a spreadsheet or a logbook kept with the equipment.
What should be recorded in a maintenance log?
The equipment by its tag, the date, the work type, the work order number, the condition as found, the work done, the failure mechanism, cause and action as codes, the parts used, the labour hours, the downtime start and end if the equipment stopped, any measurements with their units, and who did the work. The condition as found is the part most often left out and the most useful later.
Is there a maintenance log template?
The free template with this guide is an Excel workbook with one row per piece of work, drop-down lists for the work type, failure mechanism, cause and action, downtime worked out from its start and end, and a summary sheet that counts breakdowns, corrective jobs, downtime and labour for any equipment tag you type. It follows the same structure a CMMS work order history uses, so it can be loaded into one later.
What is the difference between a maintenance log and a shift log?
A shift log records what happened on the plant during a shift, across all equipment, so the next shift and the office know. A maintenance log records the work done on each piece of equipment over its life, so its history can be read and analysed. Defects found in a shift log become work requests, and the work done on them becomes entries in the maintenance log.
How long should maintenance records be kept?
For the life of the equipment at least, because the value of the history grows with its length. Some records also have legal retention periods, such as those for pressure equipment, lifting equipment and statutory inspections, which the relevant regulations set. A CMMS keeps the history automatically. A paper logbook should go with the equipment if it moves.
Key terms
Plain-language definitions from our glossary for the concepts this article leans on.
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