How do you estimate field commissioning hours?

Divide the workload by the completion rate for a base time, then multiply by the allowance factor. With 120 units at 12 units per minute and a 10% allowance, base time is 10 hours and required time is 11 hours.

Why add a setup and delay allowance?

The raw rate assumes uninterrupted work. In reality crews spend time on lockout-tagout, moving between the shield and gantries, waiting on a client witness, and re-testing. The allowance — 10% here — folds that unavoidable overhead back into the estimate.

What's the difference between base time and required time?

Base time (10 hours here) is the pure task time at the completion rate. Required time (11 hours) adds the allowance for setup and delays. Always schedule to required time, not base.

What is a good completion rate for commissioning?

There's no universal figure — it depends how you define a task or test point. The value matters most for consistency: measure your rate against your own historical commissioning campaigns and hold the definition of a 'unit' constant so estimates stay comparable.

Does this cover fault-finding and rework?

Only to the extent your allowance percentage captures it. A steady completion rate can't model a failed main-drive megger test that stops everything for half a shift. For fault-prone machines, raise the allowance or add a separate contingency.

How do I reduce field commissioning time?

The biggest wins come from pre-commissioning as much as possible during factory acceptance testing, so fewer test points remain in the field, and from sequencing tasks to eliminate setup and access delays that inflate the allowance.

Tunnel Boring & Heavy Civil Equipment calculator

Field Commissioning Hours Calculator

Field commissioning hours estimates the labor time to bring a tunnel-boring machine from a fully assembled but cold state to a proven, ready-to-mine condition at the launch shaft — powering up drives, testing hydraulics, calibrating the guidance system, and clearing each function through its test points. Commissioning engineers and launch-schedule planners use it to size the on-site crew and to protect the launch date, because commissioning is the last activity standing between the client and first advance. The model takes the number of commissioning tasks or test points, the rate at which the crew clears them, and an allowance for setup, handling, and delays, then returns both the base and the buffered time. Underestimating it is a classic cause of a slipped tunnel start.

What this calculator does

Estimate field commissioning hours for tunnel boring and heavy civil equipment using production-ready inputs so teams can plan labor hours, schedule the work, or check whether the job fits the available shift time.
Use it when field commissioning hours in tunnel boring and heavy civil equipment is changing rate or allowance and you want to see the impact.
It divides the commissioning workload by the completion rate to get a base time, then inflates it by the setup and delay allowance to get the required time.

Formula used

Base field commissioning hours time = field commissioning hours workload ÷ field commissioning hours completion rate
Required field commissioning hours time = base field commissioning hours time × allowance factor

Inputs explained

Field commissioning tasks or test points:
Commissioning completion rate:
Setup, handling, and delay allowance:

How to use the result

Use it when building the launch-window schedule or sizing the commissioning crew before the machine is energized at the shaft.
It assumes a steady completion rate, but commissioning is punctuated by fault-finding — a single failed pressure test or guidance fault can consume hours the average rate never sees.

Current U.S. benchmarks

Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% year over year (Census).

Common questions

How do you estimate field commissioning hours? Divide the workload by the completion rate for a base time, then multiply by the allowance factor. With 120 units at 12 units per minute and a 10% allowance, base time is 10 hours and required time is 11 hours.
Why add a setup and delay allowance? The raw rate assumes uninterrupted work. In reality crews spend time on lockout-tagout, moving between the shield and gantries, waiting on a client witness, and re-testing. The allowance — 10% here — folds that unavoidable overhead back into the estimate.
What's the difference between base time and required time? Base time (10 hours here) is the pure task time at the completion rate. Required time (11 hours) adds the allowance for setup and delays. Always schedule to required time, not base.
What is a good completion rate for commissioning? There's no universal figure — it depends how you define a task or test point. The value matters most for consistency: measure your rate against your own historical commissioning campaigns and hold the definition of a 'unit' constant so estimates stay comparable.
Does this cover fault-finding and rework? Only to the extent your allowance percentage captures it. A steady completion rate can't model a failed main-drive megger test that stops everything for half a shift. For fault-prone machines, raise the allowance or add a separate contingency.

Last reviewed 2026-05-12.