Editing Economies of scale (section)

===Physical and engineering basis: economies of increased dimension===
Some of the economies of scale recognized in engineering have a physical basis, such as the [[square–cube law]], by which the surface of a vessel increases by the square of the dimensions while the volume increases by the cube. This law has a direct effect on the capital cost of such things as buildings, factories, pipelines, ships and airplanes.{{efn|See various estimating guides, such as Means. Also see various engineering economics texts related to plant design and construction, etc.}}

In structural engineering, the strength of [[Beam (structure)|beams]] increases with the cube of the thickness.

[[Drag (physics)|Drag]] loss of vehicles like aircraft or ships generally increases less than proportional with increasing cargo volume, although the physical details can be quite complicated. Therefore, making them larger usually results in less fuel consumption per ton of cargo at a given speed.

Heat loss from industrial processes vary per unit of volume for pipes, tanks and other vessels in a relationship somewhat similar to the square–cube law.{{efn|The relationship is rather complex. See engineering texts on heat transfer.}}{{sfnmp|Robinson|1958|1pp=22-23|Scherer |1980|2pp=82–83|Pratten|1991|3pp=16-17}} In some productions, an increase in the size of the plant reduces the average variable cost, thanks to the energy savings resulting from the lower dispersion of heat.

Economies of increased dimension are often misinterpreted because of the confusion between indivisibility and three-dimensionality of space. This confusion arises from the fact that three-dimensional production elements, such as pipes and ovens, once installed and operating, are always technically indivisible. However, the economies of scale due to the increase in size do not depend on indivisibility but exclusively on the three-dimensionality of space. Indeed, indivisibility only entails the existence of economies of scale produced by the balancing of productive capacities, considered above; or of increasing returns in the utilisation of a single plant, due to its more efficient use as the quantity produced increases. However, this latter phenomenon has nothing to do with the economies of scale which, by definition, are linked to the use of a larger plant.{{sfnp|Morroni|2006|pp=169-170}}