Building envelope: assessment and certification of its performance. The rating

The envelope rating system’s aim is to spot elements that can objectively identify the level of "quality" of a building envelope. The purpose of this system is to support the design of building envelopes and it wants to clarify if indeed a redevelopment may or may not be functional in terms of technology in order to reduce energy consumption of buildings. The system can be applied to: - existing buildings to assess the performance characteristics of the building envelope; - buildings not yet constrict in order to simulate various scenarios and realize the most suitable type of building envelope. Starting from the study of the national and international rating systems existing, five areas of analysis have been identified in the envelope rating system and each of them has been divided into groups and subgroups. These are: 1. building envelope (frames, systems for enhanced daylight control, etc.); 2. technological performance (energy class, transmittance, etc.); 3. intelligence systems (solar technologies, etc.); 4. security systems; 5. maintenance. Each area of analysis has received a weighted score according to its level of importance. The representation of the rating system’s results occurs through the use of certain histogram charts in which the maximum achievable scores and those actually achieved for each group and subgroup analyzed before and after redevelopment, are highlighted in absolute value. In conclusion the rating system enables to obtain a total score, expressed in hundredths, that classifies the level of “quality” of the building envelope. Depending on the score obtained, it is possible to associate the building under analysis to a specific code that will define the value of rating. This score is described by a radar chart that represents the marks obtained for each area of analysis given in percentages, made 100 the highest score achievable for each area of assessment.