ABSTRACT
Abstract The Meaning of "Life" reports on the development of a knowledge-based expert
system, which uses degradation curves and actuarial tables to manage and sustain facilities in the United States. This report details the results of a 20-year research and development effort that
produced this expert system. The system is designed to manage existing facilities and provide renewal strategies for the systems and components that make up a facility. This system is currently being used in the United States to manage components of a 50 billiondollar inventory of building assets. The care of the built environment has historically been under-funded, in a large part
due to the vagueness of the term "life." How long will my roof last? What is its life expectancy? How long will a boiler last? What is its life expectancy? The answers to these questions have previously been subjective. That subjectivity has
added to the innate tendency of owners to fail to plan for the renewal of the building systems and components. The actuarial tables and the degradation curves contained in this expert system allow for the redefining of the term service life to an objective, measurable and an auditable statement. ''That period of time, during which, it is more cost effective to maintain an asset than it is to fund the annualized replacement cost is called service Iife--or period of serviceability." Owners, architects, engineers, and builders need to be aware of the various depletion
rates produced because of system and component selection. They must manage these depletion rates if unnecessary costs in facility operations and maintenance and untimely capital expenditures are to be avoided. Key Words: Serviceability, Actuarial, Objective, Subjective, Depletion, Depreciation, Deduct, Deteriorate, Actuarial Projection of Service Life (APSL)
1 Introduction
Those responsible for managing the built environment are responsible for an asset (facilities) that typically represents 25 to 40 percent of their organizational net worth. Yet they are not organized, charted, or funded to manage this huge portfolio as an asset.
