As some types of industrial buildings get bigger, there are economies of scale that make them more efficient to measure.
- A certain portion of the building will consist of corridors, doors, windows, stairs, washrooms, offices and other elements that are always of the same ‘scale’. The work to measure these areas will have a linear relationship to their area.
- Other areas such as warehouses and the factory floor will be very efficient to measure. The marginal cost of measuring bigger open spaces will decline as the areas increase.
Project Cost
Based on a statistical analysis of past projects, we found that the cost of measuring industrial buildings was approximately related to:
Cost = X * (Area ^ 0.7)
Where:
- Cost is in dollars
- Area is in square feet
- X is an adjustment factor for complexity. The value of X is affected by the building type, the amount of existing information, and the required degree of detail in the final drawings.
Intuitively this makes sense because the effort required to measure the office and support areas will increase in direct proportion to the area. The effort required to measure elements of the perimeter walls, in the large open areas, will increase only with about the increase in linear length of these walls. So the power should be between 0.5 and 1.
As a graph, this relationship is an upward sloping curve with decreasing slope. The curve shown is only an example. The position of the curve would depend on the components of X – the complexity factors.
Square Foot Rates
To get the square foot rate, we divide both sides by the area. The cost per square foot is therefore:
(Cost)/(Area) = X*(Area ^ 0.7)/(Area) = X*(Area ^ -0.3)
The rate to measure small buildings is high. Rates drop quickly at first and then more slowly – of course, the rate never reaches zero! Again, this particular curve is only an example to illustrate the effects of scale. The actual curve and the actual costs would depend on many other factors.
Application
In reality, all buildings are unique and there will never be a single rate or formula that can replace sound judgment and experience in terms of estimating project costs. But this model at least provides a framework for understanding how these economies of scale behave.
