# Adaptation of the SBTool for Sustainability Assessment of High School Buildings in Portugal--SAHSBT
## 3 Materials and Methods
#### Categories and Indicators  
The main objective of these indicators is to quantify, simplify, and communicate some characteristics of the buildings. The combination of several indicators forms a category. There are large differences between the indicators used in different methodologies for evaluating the sustainability of school buildings due to the economic, environmental, and socio-cultural differences and the technologies in each country [3]. The LEED (US), BREEAM (UK), and SBTool (Canada) methodologies were initially developed according to the realities of their original countries, and later, they were adapted to the circumstances of each country in which they were applied. In this section, all the indicators and categories of the SAHSBT are presented together with an explanation of why they were chosen and a comparison with similar indicators belonging to other methodologies applicable to schools, such as LEED BD + C Schools, SBTool International for School, and BREEAM Education. **C1. CLIMATE CHANGE AND OUTDOOR AIR QUALITY**  
Over the years, excessive CO2 emissions have given rise to climate change. It is necessary to seek new proposals to reduce CO2 emissions, in order to avoid or reduce the consequences of this phenomenon. This category includes two indicators: \"life cycle environmental impacts\" (I1) and \"heat island effect\" (I2). **Indicator 1--Life cycle environmental impacts**  
The objective of this indicator is to encourage and promote the use of materials and construction solutions that have low environmental impact. It was not possible to investigate the constructive solutions used in school buildings in Portugal, because it was not viable to carry out such an exhaustive study. The calculation method used for this indicator is the same as that used in the SBToolPT-STP for Office Buildings and SBToolPT-H [3]; therefore, this indicator is similar to those used in these previous methodologies. The same database, reference practice, and method of calculation were used in this research in order to maintain the standard of SBTool methodologies adapted to Portugal. According to these methodologies, first, the environmental impacts of the life cycle of the building are quantified, and then, these impacts are quantified with respect to the reference building. **Indicator 2--Heat island effect**  
The objective of this indicator is to promote the use of green areas located in the outer area of the building and materials with high reflectance to reduce the heat island effect in urban areas. Portugal maintains schools built in different historical periods; nevertheless, using a significant variety of materials and constructive processes, their facades are usually made to be white or other light tones, and their roofs are usually made with ceramic or metallic tiles. These materials support the reduction of heat island effect [21]. Currently, the construction industry favors the use of some parameters to predict the thermal behavior of materials used in facades when subjected to solar radiation, considering the interaction between different properties of the materials without using complex calculations, such as the Solar Reflectance Index (SRI) [21]. The SRI is used in the SAHSBT methodology, for its effective representation of the thermal behavior of a constructed surface subjected to solar radiation and for its ease of calculation. This indicator is similar to those used in the SBToolPT-STP for Office Buildings and SBToolPT-H.  
**C2. BIODIVERSITY AND LAND USE**  
The growth of areas used for agriculture, the destruction of forests, and the increase of urban areas are exacerbating negative environmental impacts. To minimize them, buildings must be constructed in areas that have already been occupied by other buildings. This category includes two indicators: \"land use efficiency\" (I3) and \"certificated materials\" (I4).