**3. The characterization of systems for the building design: the geographical and matter context**

Considering the breadth of material possibilities and technical solutions offered by the market for the design and construction of the building, it is a difficult task to identify choices with characteristics suitable for the reference context, from a functional, economic, and above all environmental point of view. It is necessary for designers to have a conscious and coherent knowledge of the characteristics of building components, their expected performance and their environmental impact, and a critical observation of their real validity, for the purpose of making informed technological choices. The market seems to reward products that do not address the complexity of the problem, but only buffer it apparently, often responding to trends or "symptoms of the moment." This attitude only creates further confusion superficiality and lack of clarity. The choice of a component must not only be determined by its compliance with a function, but in the broader perspective of the use that will be made of it, a specific use linked to the environmental, temporal, and social context. In addition to the question "which form for which function," "which technology for which building," and "which material for which context" must immediately be correlated. The context, as well as in a static sense (the physical place), is linked to the use and users in a dynamic sense, with modifications and different approaches over time. A building arises from a specific, localized project pertinent to a technical and material culture, which is, even if not deriving from the whole, at least in part related to the society that produces it.

It is not enough to characterize the choice of materials and components for the building on the basis of product certifications, the CE quality marking of the manufacturing company or on technical sheets validated by scores on the level of eco-compatibility of the product. Extreme awareness of the environmental profile of the component contextualized with respect to the building in which it will be located is required; a choice of a component must be verified every time it is decided to insert it in a building in relation to the specific geographical, urban/suburban context. Each project, therefore each building, has its own story with respect to others or with respect to the context.
