11.5 Commissioning: Pre-Start Checks, Run-In & Documentation
Key Takeaways
- Commissioning verifies mechanical completion, then proves the equipment performs to specification under progressively increasing load before it is handed to operations.
- Motor rotation must be confirmed uncoupled before a pump, fan or compressor is coupled, because reverse rotation can destroy an impeller, a seal or a screw element in seconds.
- Baseline readings — vibration, bearing temperature, current draw, alignment values and flow or pressure — are recorded at commissioning and become the reference for all future condition monitoring.
- Hot alignment checks after the machine reaches operating temperature confirm that the cold offsets compensated thermal growth correctly.
- A commissioning package is not complete until as-built drawings, test records, baseline data, lubrication charge details and operator training are all documented and handed over.
Task F-24 (Commissions and decommissions equipment) carries 5 exam questions. Section 11.2 covers decommissioning; this section covers F-24.01 (Commissions systems and components) — the disciplined sequence that turns an installed machine into a machine that will run reliably for twenty years.
The Commissioning Sequence
MECHANICAL -> PRE-START -> UNCOUPLED -> COUPLED -> LOADED -> HANDOVER
COMPLETION CHECKS SOLO RUN NO-LOAD RUN RUN-IN PACKAGE
installed, static motor rotate the progressive as-builts,
aligned, verification rotation, train, check load steps, baselines,
torqued, of every current, vibration full duty, training,
lubricated system vibration and temps performance sign-off
Each gate must pass before the next begins. Skipping a gate is how new equipment fails in its first week.
Stage 1 — Mechanical Completion Verification
| Check | What to confirm |
|---|---|
| Foundation and grout | Grout cured and sound, anchor bolts torqued to specification, no voids under the baseplate (hammer test) |
| Soft foot | Corrected and documented, within about 0.05 mm (0.002 in) at every foot |
| Alignment | Final cold alignment recorded, including the thermal-growth offsets used (section 10.2) |
| Piping | Pipe strain checked with a dial indicator at the flanges; supports and hangers set (section 14.1) |
| Fasteners | All bolts torqued to specification and marked; couplings, guards and access covers secure |
| Guards | Every rotating component guarded, guards secure and correctly fitted |
| Lubrication | Correct lubricant grade and quantity in every sump, bearing and gearbox; sight glasses at the correct level; grease points charged; auto-lubricators set and dated |
| Cleanliness | Systems flushed; hydraulic and lube circuits flushed to the target ISO cleanliness code before the machine runs on them |
| Instrumentation | Gauges, thermowells, vibration sensors and switches installed, calibrated and readable |
| Rotation by hand | Turn the train by hand to confirm it is free, with no rubbing or binding |
Stage 2 — Pre-Start Checks and Permits
- Confirm all construction lock-outs are removed and the correct operational isolation state exists.
- Verify electrical checks are complete — megger and continuity tests, overload settings matched to nameplate FLA and service factor (section 4.2), and control wiring proven.
- Confirm safety devices are functional and not bypassed: vibration switches, temperature switches, low-flow and low-level trips, belt-slip and misalignment switches, emergency stops, and interlocks. Never commission with a protective device jumpered out.
- Confirm cooling water, seal flush, purge gas and instrument air are lined up.
- Clear and barricade the area, brief everyone involved, and assign roles including who has authority to stop.
Stage 3 — Uncoupled Solo Run of the Driver
Always confirm motor rotation with the coupling disconnected. Reverse rotation will:
- Unscrew a threaded pump impeller and wreck the pump in seconds.
- Run a rotary screw compressor backward and destroy the element.
- Reverse a fan's flow at drastically reduced volume, hiding the fault until the process fails.
- Drive a positive-displacement pump against a closed suction and burst a line.
With the coupling out:
- Bump the motor and confirm rotation against the arrow on the casing.
- Run the motor solo, and record no-load current, vibration and bearing temperatures.
- Confirm the direction again if the electrical connection is changed at any point afterwards.
Stage 4 — Coupled No-Load Run
Reconnect the coupling to the recorded alignment, fit the guard, and run the train unloaded (recirculation valve open, damper closed, or clutch disengaged as applicable):
- Watch for the first minutes continuously, listening for rubs, and be ready to stop.
- Record vibration at every bearing in three directions, bearing temperatures, and current.
- Check for leaks at every joint, seal and fitting under real running pressure.
- Confirm oil flow at every sight glass and return line, and that the seal flush is proven.
- Let the machine reach thermal equilibrium — usually one to four hours — while monitoring temperature trends toward a stable plateau.
Stage 5 — Progressive Load Run-In
Load the machine in steps, commonly 25%, 50%, 75% and 100%, holding at each step long enough for temperatures to stabilize. At each step record:
- Vibration (overall level and spectrum), bearing and winding temperature, current and power.
- Process values — flow, suction and discharge pressure, differential pressure, speed.
- Any noise or behaviour change.
Compare against the manufacturer's acceptance criteria and the design duty point. A pump that will not make its head at rated flow, or a fan drawing more power than the curve predicts, has an installation or a system problem that must be resolved before handover, not after.
Break-in requirements matter on specific equipment: new gearboxes often require a break-in oil change after a short initial run (commonly 100–500 hours) to remove the metal debris generated as gear teeth bed in, and new V-belt drives need re-tensioning after the initial run-in period because they seat and lose tension quickly.
Stage 6 — Hot Alignment Verification
Once the machine has reached stable operating temperature, shut it down, lock out, and re-check the alignment immediately while hot. This confirms that the thermal-growth offsets applied cold actually brought the machine into alignment at temperature. A machine that was aligned within tolerance cold and is now out of tolerance hot needs its offsets corrected — the calculation was wrong, or the growth is not what the manufacturer predicted.
Stage 7 — Baseline Data and Handover
Baseline data captured at commissioning is the single most valuable maintenance asset a machine will ever have, because all future condition monitoring is a comparison against it.
| Baseline record | Why it matters |
|---|---|
| Vibration spectra at every bearing | The signature of a healthy machine; future spectra are compared to it |
| Bearing and winding temperatures at each load step | Establishes the normal thermal profile |
| Motor current and power at each load step | Detects future increases in mechanical drag |
| Final alignment values, cold and hot | Reference for future alignment checks |
| Process performance data | Proves the duty point and provides a degradation reference |
| Thermographic images | Baseline heat pattern of couplings, bearings, and electrical connections |
| Lubricant type, quantity and a new-oil sample | Reference for all future oil analysis |
The handover package must include:
- As-built drawings and P&IDs with all field changes redlined and incorporated.
- Completed inspection and test records with sign-offs.
- Manufacturer manuals, spare parts lists and recommended spares holding.
- Lubrication schedule and chart entered into the CMMS.
- Preventive-maintenance job plans and intervals loaded into the CMMS.
- Warranty terms and start date.
- Operator and maintainer training, delivered and documented.
- A formal sign-off transferring custody from the project or maintenance group to operations.
A machine is not commissioned when it runs. It is commissioned when it has been proven to specification and the documentation, baselines and training exist to keep it that way.
A new end-suction centrifugal pump has been installed, aligned and lubricated. What must be verified before the coupling is connected?
A new motor-and-gearbox train is aligned within tolerance cold, runs well through its load steps, and is handed over. Two months later it shows high 2x running-speed vibration typical of misalignment. What commissioning step was most likely omitted?
During commissioning of a new fan, a low-flow trip repeatedly stops the machine during the 25% load step. The project is behind schedule and a supervisor asks that the trip be jumpered out so the run-in can be completed. How should the millwright respond?