Based on submitted comments and discussion in ISO/TC59/Sc17/W4, the paper discusses the requirements to the methods of environmental performance assessment to ensure comparability of results of assessment by different methods. It shows five categories of environmental issues of concern by stakeholders of building that could be involved as a basis of criteria of assessment methods. The paper identifies there exist significant differences in the scope of involves issues, because of regional based biases as well as technical feasibility. Respecting on interdependencies of those categories of environmental issues, the paper indicates structural analysis method using the idea of concept network diagram. The agreed and standardized diagram could be the first step to realize compatibilities. The paper emphasizes that the clear statement of system boundaries, setting assumptions and information source is also significant requirements to assure comparability of the different methods.
