Review of Non-Destructive Techniques (NDTs) for Building Diagnostic Inspections

Understanding building envelope thermodynamics is an essential foundation of building sciences, mainly due to the envelope's role as a boundary layer for exterior environments, as well as container and regulator of internal microclimates. This paper presents a systematic literature review of the various Non-destructive Testing (NDT) for building envelope scanning and surveying for thermodynamic diagnostics. The aim is to identify knowledge gaps in terms of their use in accurately characterizing envelope compositions for further integration in Building Energy Modeling (BEM). Each NDT was evaluated according to set categories imbibed from ASHRAE Standard 211 that showcase the NDTs ability to extract various relevant information. A framework is then developed to inform users on how to use hybrid NDT-based workflows applied in building envelope energy audits. The paper concludes by discussing possibilities of utilizing NDTs in large-scale audit automation, BEM integration, and developing built environment policies focusing on increasing existing building performance through retrofitting design.