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Steps to Estimate Activity Resource Unit (Budgeted Labor Unit) for P6

The sequence of steps producing budgeted labor unit of each activity as follows;

Study design and construction methodology
It is assumed that you are a mechanical construction contractor. You got a project requires installing a pipe rack for a chemical plant. Construction drawings are provided by engineering contractor. According to layout drawings and isometric drawings, a layer of pipe rack is to be erected on an elevated new steel structure. Pre-fabricated steel structure is to be erected on the foundations done by other. The new pipe rack header is to be connected with existing facility. Field welding, flanges and threads fitting, bolting, field pipe supports, NDT (X-Ray etc.) test and hydrostatic test are to be performed. Pre-fabricated piping and structure members are already on site delivered by engineering contractor. Scaffolds and crane are required to erect piping and steel work.

Prepare material take-off onthe layout drawings, detailed drawings and specifications

Tabulate the following construction quantities in the estimate spreadsheet.

(1)    Tons of steel per member

(2)    Numbers of field welds joints to be welded for each pipe size and drawing

(3)    Numbers of NDT joints for each pipe size and drawing

(4)    Numbers of pipe meter run to be erected for each size and drawing

(5)    Numbers of pipe meter run to be hydro tested for each size and drawing

(6)    Numbers of flange joints to be bolted for each size and drawing

(7)    Numbers of threaded fitting to be fitted for each size and drawing

(8)    Tons of field pipe supports to be erected for each drawing
Define Activities to be performed

It is assumed that the following activities are defined based on the above scope and construction methodology.

(1)    Erect steel members

(2)    Erect supports for big bore piping

(3)    Erect big bore piping (6” and above)

(4)    Field welds and NDT – big bore

(5)    Field welds and NDT– small bore

(6)    Erect small bore piping (less than 6”)

(7)    Erect field supports for small bore piping

(8)    Hydro static testing
Calculate erection man hours, estimate man hours

The man hour calculation is made by multiplying construction quantity by the man-hours schedule used in, for instance “Estimator’s Piping Man Hour Manual”, “Estimator’s equipment installation Man Hour Manual”, and OCPCA data bank of estimating norms.
Man hour rate of erection could be different depending on geographical, environmental, market and political condition of the location.
Populate the construction quantities for each drawing on an estimate spreadsheet and multiply with man hour schedule to derive man hour per each type of work.

Sum up the total man hours of each drawing into summary activity level (level 3) so that it's budgeted labour unit can be entered into P6.  For instance, budgeted labor unit of (1) Erect steel members = 800 hours. Then, earned value report can also be produced based on these budgeted labor units and actual spent.

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