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?
That the motor rotation matches the direction arrow on the pump casing, verified by bumping the motor with the coupling disconnected
That the suction strainer differential pressure is within limits
That the seal flush flow rate has stabilized
That the discharge valve is fully open so the pump does not deadhead
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?
The coupling should have been replaced with a rigid type
A hot alignment check after the machine reached stable operating temperature, to confirm that the cold thermal-growth offsets actually brought it into alignment at temperature
The gearbox should have received a synthetic lubricant
The baseline vibration data should have been taken at a higher resolution
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?
Raise the trip setpoint above the operating value permanently
Jumper the trip and remove the jumper after the run-in is finished
Refuse: protective devices must be functional throughout commissioning, and a repeated trip is evidence of a real installation or process problem that must be resolved before load is increased
Jumper the trip but stand by the emergency stop for the duration
Sections you finish are checked off in the contents.