This is the companion reference for our guide to machine downtime. It is a two-level downtime reason-code taxonomy, family → category → code, sized so an operator can pick the right code in under ten seconds. Copy it, rename codes to match your floor's vocabulary, and delete anything that does not apply.
Planned downtime codes
| Code | Name | Use when… |
|---|---|---|
| PL-PM | Preventive maintenance | The stop was scheduled maintenance work, executed in its planned window. |
| PL-CO | Changeover / setup | The line is being converted between products, formats, or tooling. Time the full stop-to-first-good-part interval. |
| PL-CLEAN | Cleaning / sanitation | Scheduled cleaning, washdown, or CIP. |
| PL-NO | No order scheduled | The line is idle because nothing is scheduled to run. Exclude from availability if the time was never planned production time. |
| PL-TRIAL | Trial / engineering | Planned experiments, samples, validation runs. |
| PL-MEET | Meeting / training | The crew is in a scheduled meeting or training and the line is stopped for it. |
Unplanned downtime codes
| Category | Code | Name | Use when… |
|---|---|---|---|
| Equipment | EQ-MECH | Mechanical failure | A mechanical component failed: bearing, belt, chain, gearbox, cylinder. |
| EQ-ELEC | Electrical / controls | Electrical or controls fault: drive, sensor, PLC fault, wiring. | |
| EQ-TOOL | Tooling | Tooling, dies, blades, or change parts worn, broken, or out of adjustment. | |
| Process | PR-JAM | Product jam | Product jammed or misfed and had to be cleared. Log even sub-minute jams if capture allows. |
| PR-ADJ | Minor stop / adjustment | Brief stop to adjust guides, feeds, settings, no failure, no jam. | |
| PR-QUAL | Quality stop | Line stopped because output was out of spec or a quality check failed. | |
| Material | MA-STARVE | No material at station | Line stopped waiting for material that was not delivered to the station. |
| MA-DEF | Defective material | Incoming material would not run: out-of-spec components, bad film, warped stock. | |
| MA-WRONG | Wrong material staged | The material at the line was the wrong item, grade, or revision. | |
| Flow | FL-BLOCK | Blocked downstream | The machine could run but downstream equipment or buffers were full. |
| FL-WAIT | Starved upstream | The machine could run but upstream equipment was not supplying it. | |
| Labor | LA-NOOP | No operator | Line stopped because no qualified operator was available to run it. |
| LA-CHG | Shift-change gap | Stop during shift handoff beyond the planned overlap. | |
| Utilities / external | UT-PWR | Power loss | Electrical supply interruption, brownout, breaker trip at supply level. |
| UT-AIR | Air / steam / water loss | Compressed air, steam, chilled water, or other utility below spec. |
Rules for using the taxonomy
- Two levels, one screen. Category first, then code. If the operator has to scroll, the list is too long. Target 15–25 codes.
- One physical meaning per code. If two people could reasonably file the same stop under different codes, tighten the definitions.
- Code the first cause the operator can see. Root-cause analysis comes later; the floor codes what happened, not why it ultimately happened.
- Cap "Other" at 10%. If an Other/uncoded bucket exceeds roughly 10% of coded minutes, a real cause is hiding in it. Find it and give it a code.
- Review quarterly. Merge codes nobody uses. Split codes that dominate the Pareto but hide multiple distinct causes.
- Never punish the code. The day a reason code is used against an operator or a crew is the day the data goes bad. Codes describe the line, not the people.
To turn coded minutes into dollars, use the downtime cost calculator, and see the full tracking-and-reduction loop in the machine downtime guide.