BETB Guide Backstory and Innovation.
The Building Envelope Thermal Bridging (BETB) Guide has defined my career to a large extent for the past decade. How the BETB Guide supported the adoption of requirements for comprehensive thermal bridging calculations in energy codes and standards is rewarding. However, celebrating this success is not what I wish to highlight. I wish to highlight the inception story behind the BETB Guide, why and how this happened, and how I see Evoke responding to the evolving expectations in the next decade for the built environment.
The BETB Guide’s inception can be traced back to circa 2008-2009 and the lead up to the Olympics in Vancouver. The challenge of the day was LEED Platinum and how to meet the effective R-values using wall assemblies that were not common at the time. Energy modelling and exterior insulated walls for Part 3 buildings were not as prevalent as they are today with the BC Energy Step Code and we did not have proprietary cladding attachment systems with performance backed up with data.
During this era, I was the guy doing the 2D (THERM) thermal analysis to determine how to meet the specified effective R-values. We did not have tables to look up solutions. Every change to the energy model and round of value engineering resulted in many new models, a lot of effort, clients waiting for answers, and more meetings. There needed to be a better way.
In response, I asked myself the question “how can I provide information to the design team, so the team is empowered to make decisions without a fragmented design approach?”. This led to us developing generic solutions, in advance of meetings, for various cladding attachments and insulation levels. We presented the results in a way that aided decision making and reduced the need for project specific analysis. The team at Morrison Hershfield wrote a paper about it. This work helped us secure a research project ASHRAE 1365-RP that explored the impact of thermal bridging using 3D Thermal modeling.
ASHRAE 1365-RP provided the bedrock for the methodology presented in the BETB Guide by validating the modelling procedures and clearly explaining why North America needed to adopt the concept of linear transmittance. The work done for ASHRAE 1365-RP and subsequent efforts to increase awareness led to the first BETB Guide, which had a BC focus.
The first version of the BETB Guide addressed questions that were raised after ASHRAE 1365-RP, such as the impact of thermal bridging on building energy use and construction costs. The Low TEDI Guide was first initiated to address questions about how other thermal bridging methodologies compared to the BETB methodology. However, the Low TEDI Guide went beyond thermal bridging to also address questions about HRVs, the BC Energy Step Code, and design guidance for Part 3 net-zero buildings.
The BETB Guide continues to evolve to address feedback and become an essential Canadian resource for years to come by expanding the database to apply to all types of construction, climate zones 4 to 8, and current practice to what is needed for Net Zero buildings.
I am comforted by all our collective past success as I look forward at the start of our new adventure. I am truly excited for the challenges ahead and cannot wait until we are able to look back at the next decade of collaborations and accomplishments.
-Patrick Roppel
