1.1 This guide presents a common framework and set of principles for potential users, such as product manufacturers, environmental analysts, consultants, architects, and the building industry in general. It describes a framework for life cycle inventory analysis, and describes various options and aspects of Impact Assessment and Interpretation.

1.2 The complexity and level of detail of an LCA will vary greatly depending on the material/product or system studied, the purpose and use of the study, the intended users of the study, and the resources committed to complete the study. The level of detail can range from generic to material/product specific.

1.3 This guide does not describe in detail the actual techniques for performing a Life Cycle Assessment.

1.4 Life Cycle Assessment is an emerging methodology, which is still evolving. This guide will present its concepts and major features. It should enable the user to better understand Life Cycle Assessment and its application to building materials/products, and help to identify sources of additional information and guidances. LCA is only one of many tools designed to aid in environmental evaluation and decision making.

1.5 The component phases of Life Cycle Assessment, including goal definition and scoping, inventory, impact assessment, interpretation, and the various methodologies used in these phases are in various stages of development. Consequently, the results of an LCA must be understood in the context of their completeness and accuracy and must be applied appropriately. LCA does not necessarily proceed as a linear process through these phases but is conducted in a iterative fashion.