When I first set out to write this article it seemed a fairly straightforward topic. After all, ASHRAE and various other sources have researched and published equipment lifespan tables that give good advice on expected lifespans for typical equipment used in facilities. And if you want to base five- and 10-year capital plans on a generic table, then I guess it really is a simple process. But alas, the more you think about it, the more complicated and difficult it gets.
What I quickly realized is that there are multitudes of competing, conflicting, and, in many cases, ambiguous parameters that influence decisions regarding when the best time is to replace equipment. Add to this equation the idiosyncrasies of mission critical operations and the decision process can get even more (or sometimes less) difficult. Ultimately, the exercise is a financial analysis based on predictions, estimates, and best guesses. And when you consider that in many if not most cases the responsibility for performing these analyses fall upon a facilities manager instead of a finance wizard, the challenge gets even more daunting.