## 2 Background, Methodology, and Materials  
### Scope and Fundamental Definitions  
To define what a building for public use consists of, one can go to the current applicable regulations. Among the current legal texts in Spain, the Technical Building Code (CTE) [16] distinguishes different uses for a building, such as administrative, parking, commercial, educational, hospital, public attendance, public residential and residential housing or private. As can be seen within these uses, there is great versatility among those that could be defined as public or open to the public, especially considering that there are other types of buildings that could be added to this classification, such as religious, transport infrastructures or sports facilities.  
Another legal text that defines what a building for public use is Decree 158/1997, of the Accessibility Code in Castilla-La Mancha [17], where buildings for public use are considered as independent architectural units, whose exterior and interior spaces and dependencies are entirely for collective use or public attendance or constitute a work center. It is also considered a building for public use even if it has dependencies for private use or housing for functions such as surveillance or maintenance of the building. Establishments for public use are located inside buildings or facilities, whether public or private, for commercial, administrative, cultural, sports, work centers, entertainment, or meeting venues, etc. Law 8/1997, of June 18, on the Promotion of Accessibility in Extremadura [18]. The law includes an extensive list with the types of public utility buildings such as: public and services of the Public Administrations; health and care centers; rail and bus service stations; airports and helicports; educational centers, garages and collective parking lots; libraries, museums and exhibition halls; theaters, movie theaters and shows; recreational sports facilities and campsites; large commercial surfaces; religious centers, hotel facilities; bars and restaurants; banking establishments; work centers; union centers; business centers. Within these uses, buildings for public use must comply with the functions that are established for service to citizens, without forgetting that the adjoining border areas that are established to give them access or auxiliary services are also part of them. Within the cluster of public buildings, elderly residences are included. In this context, according to a report by the Institute for the Elderly and Social Services (IMSERSO), residential accommodation for people in situations of dependency can be classified according to the following criteria [19]:  
* Ownership: centers can be publicly or privately owned.
* Type of center: aimed at people who require assistance for their daily life (assisted) or not (valid), or both types of users (mixed centers).
* Type of accommodation: supervised housing, apartment blocks, residential complexes, residences, socio-sanitary and psychogeriatric.
* Number of places: classified into 3 categories: less than 50 places, between 50 and 100 places and those that have more than 100 places.
* Minimum price per place: 5 categories depending on the price charged by the institution (price per month): less than 400 euros, between 400 and 800 euros, from 800 to 1200 euros, from 1200 to 1600 euros and more than 1600 euros.