Chemical plant cost indexes

Chemical plant cost indexes are dimensionless numbers employed to updating capital cost required to erect a chemical plant from a past date to a later time, following changes in the value of money due to inflation and deflation. Since, at any given time, the number of chemical plants is insufficient to use in a preliminary or predesign estimate, cost indexes are handy for a series of management purposes, like long-range planning, budgeting and escalating or de-escalating contract costs.

Source: Wikipedia — Chemical plant cost indexes (CC BY-SA 4.0)