OAHU2023 – A Tale of Two Cities: Implications of Envelope Backstops in Recent Energy Codes

The Oahu 22nd Annual Hawaii Winter Workshop is designed to improve the skills and knowledge of design, rehabilitation and forensics professionals including consultants, architects and engineers, and developers, contractors and building system manufacturers. Join us on January 26 – 27, 2023.

More information and registration.

Session Overview: A Tale of Two Cities: Implications of Envelope Backstops in Recent Energy Codes

In the drive for increased energy efficiencies, recent energy codes are putting increased focus on the thermal performance of enclosure assemblies. One increasingly popular concept is the introduction of envelope backstops to limit the traditional energy codes approach of accommodating a shortfall in the thermal performance of the enclosure using efficiencies from other building systems. We will contrast the UA restriction approach to envelope backstops adopted in the latest City of Seattle Energy Codes and other US jurisdiction with the TEDI (Thermal Energy Design Intensity) approach adopted by the British Columbia Step Code and other Canadian jurisdictions.

We outline the particular challenge this presents for enclosure design of high-rise building using the case study from Artscape project in Vancouver, one of Canada’s tallest Passive House buildings. Examples from the Building Envelope Thermal Bridging Guide will be used to illustrate the current limitations of traditional unitized glazing systems when it comes to accounting for the impact of thermal bridging on enclosure thermal performance. We will conclude with a couple of examples of how manufacturers are adapting the design of unitized glazing system to meet this new challenge.

Learning Objectives

• Review the different ways recent energy codes are putting increased focus on the thermal performance of enclosure assemblies with a focus on the concept of envelope backstops.
• Contrast the UA restriction approach to envelope backstops adopted in the latest City of Seattle Energy Codes and other US jurisdiction with the TEDI (Thermal Energy Design Intensity) approach adopted by the British Columbia Step Code.
• Study the particular challenge this presents for enclosure design of high-rise building using examples from the Building Envelope Thermal Bridging Guide and the case study from Artscape project in Vancouver.
• Explore examples of how manufacturers are adapting the design of unitized glazing system to meet this new challenge

This session will be presented by Stéphane P. Hoffman, M. Arch., M. Eng., PE.