A tender that says “peak manpower 1,200” tells you very little. How many of those are pipe welders? When do the electricians peak? How many instrument technicians are needed for loop checks in the last three months? Forecasting skilled labor requirements by project phase answers those questions by building demand from the work itself. The method below is used by planners, construction managers and manpower providers on industrial projects.
What is a skilled labor forecast?
A skilled labor forecast is a time-phased estimate of the number of workers needed in each trade, derived from the quantities of work, the productivity expected for that work and the schedule in which it must be completed.
The forecasting method
Step 1: Break the scope into work types
Group the work by trade-relevant units: cubic meters of concrete, tonnes of steel, inch-diameters of welding, meters of cable, numbers of instruments. Each unit links to a trade.
Step 2: Apply productivity norms
Multiply quantities by a man-hours-per-unit norm for each work type. Norms come from company history, estimating databases or comparable projects. They should reflect the actual conditions: material, height, congestion, climate and whether the work is shop or field.
Step 3: Distribute man-hours across the schedule
Spread each work type’s man-hours across the activity durations in the schedule. A resource-loaded schedule does this automatically. Without one, use the activity start and finish dates and a sensible distribution curve.
Step 4: Convert man-hours to headcount
Divide monthly man-hours by the productive hours one worker provides per month, after allowing for breaks, travel to the workface, weather and permit waiting time.
Step 5: Add allowances
Add absenteeism, leave, rotation relief and replacements in transit. A crew that needs ten welders on the tools every day needs more than ten on the roster.
A worked example
The figures below are illustrative, not benchmarks.
A piping package carries an estimate of 48,000 welder man-hours, to be completed over eight months. If the work were spread evenly, that is 6,000 man-hours a month. Assuming each welder provides about 230 productive hours per month, the average requirement is around 26 welders.
Work is never spread evenly. If the schedule loads the middle months more heavily, the peak may be well above the average, perhaps 35 to 40 welders, with fewer at the start and end. Adding allowances for leave and absence raises the roster figure further. That peak number, not the average, is what recruitment must deliver.
Typical demand by project phase
| Phase | Trades in highest demand | Planning note |
|---|---|---|
| Civil and foundations | Carpenters, steel fixers, operators | Front-loaded, tapers as steel starts |
| Structural steel | Erectors, structural welders, riggers | Depends on fabrication deliveries |
| Mechanical and piping | Pipe fitters, pipe welders, mechanical fitters | Usually the overall peak |
| Electrical and instrumentation | Electricians, cable crews, instrument fitters | Peaks late, often compressed |
| Pre-commissioning | Instrument technicians, electricians, mechanical technicians | Smaller crews, higher skill |
The trades themselves are described in skilled trades required for industrial construction projects.
Adjustments that change the numbers
- Climate: summer heat and midday working restrictions in the Gulf reduce productive hours.
- Congestion: many trades in one area slows everyone down.
- Shift patterns: night shifts usually carry lower productivity.
- Overtime: extended hours raise output at first, then productivity per hour falls if they continue for weeks.
- Learning curve: new crews take time to reach steady productivity on an unfamiliar site.
From forecast to action
The forecast becomes useful when it drives two things: the multi-discipline manpower histogram that shows total demand, and the requisitions that start recruitment early enough, as described in how to define a technical manpower requisition. Forecasts should be refreshed monthly against actual progress, because a slip in one discipline shifts demand for the next.
Apex Core Engineering builds labor forecasts as part of its workforce planning service, linking demand by trade and month to recruitment and mobilization timelines.
Frequently asked questions
Where do productivity norms come from?
From company historical data, estimating references and comparable projects, adjusted for the specific conditions of the site and the work.
Why does peak demand matter more than average demand?
Because the project must recruit, accommodate and supervise the peak number. Planning for the average leaves the project short exactly when the most work is available.
How often should a labor forecast be updated?
Monthly is common, and more often during ramp-up and peak, when changes in progress have the largest effect on demand.
Get a labor forecast for your project from Apex Core Engineering.