Security, Energy, Embodied Carbon: Balancing Envelope Performance Goals in Glazing Design

The use of glazed facades is a common feature in buildings. With evolving environmental factors caused by climate change, building and energy code requirements, and security priorities from clients and occupants, the expectations for building glass have risen in the global market. However, meeting these expectations can be challenging for designers as designing to security standards requires the use of more, while sustainability targets often benefit from the use of less. As such, special consideration must be given to the design of glazing systems to balance the sustainability and security goals of a project. Glass design affects sustainability outcomes like embodied carbon and energy performance. Industry standard blast-resistant glazing is comprised of laminated, heat tempered layers. The glass panes may be thickened from the baseline design, and even more so if forced entry and ballistic threats are an area of concern. The additional material used in security glazing and the extra energy required to manufacture heat tempered glass all work against reaching sustainability goals. Synergies between security and sustainability goals in glazing design are not immediately apparent. With the seemingly conflicting priorities between sustainable and secure glazing, designing glazing to meet both goals can be challenging. The intent of this paper is to provide guidance and support for designers by identifying possible linkages or contradictions between glazing security and sustainability performance. System comparisons will be drawn using industry standard security and sustainability performance metrics such as fragment flight distance, embodied carbon, and thermal performance to quantify the impact that different glazing layups have towards achieving sustainability and security goals.