Simplify Building Envelope Design

How Canadian architects can simplify building envelope design – in conversation with Brian Lieburn

Building code is complicated but complying doesn’t have to be. We’ve made a simple method for architects to evaluate wall system options.

Ensuring that architects meet code requirements for wall assemblies in Canada can be challenging, expensive and confusing. The reality for architects, however, is that these requirements need to be understood early in the design process to pave the way for a well-constructed building that adheres to code.

To support the process for architects designing wall assemblies that follow fire code requirements in particular, Dow released a self-guided Commercial Code Assessment Engine (CAE) in Canada in 2017.

Largely involved in the development of the CAE is Brian Lieburn, residential applications technology leader at Dow. In his role, he works in R&D and listens to builders, architects, code officials, among others regarding any challenges they have in their respective positions so he can derive what new solutions would be most helpful to their businesses. What follows is a conversation about why the CAE was needed for architects in Canada.

Why is the Code Assessment Engine important for architects?

Canada is committed to improving building energy efficiency, and that’s not going to change. Newer energy codes require buildings to be more efficient by using the most effective insulation, air sealing, windows, heating and cooling systems. The CAE helps architects meet these high standards for energy efficiency by showing them different design strategies and broadening the technologies available for achieving higher performing building envelopes.

What does this mean for the enclosure?

For the enclosure this means more insulation and reduced air leakage. Foam plastic insulation allows architects to use continuous insulation using higher R-value per inch materials. However, requirements in the National Building Code Canada (NBCC) for the use of foam plastic insulation can get very complicated. In the past, this meant architects were either confused about the best way to meet those requirements or if they are going to use foam plastic insulation they would have to get a fire consulting engineer involved early on in the process. It was complicated. But now, even if a fire consulting engineer is desired, architects can quickly assess their options based on their project needs.

What does the CAE allow?

The Code Assessment Engine allows the user to enter project characteristics and wall assembly variables that they want to try in their designs. The CAE basically lets them know they can use foam plastics in that application, for example, and proceeds to tell them how to protect the foam plastics on the inside and outside of the building, which allows them more design flexibility overall.

How might the CAE change the way architects and building envelope specialists in Canada design their projects?

Prior to the Code Assessment Engine, architects would often need to consult fire engineering consultants early in the planning stages before determining wall assemblies. The CAE allows architects to experiment with various wall assembly configurations to help determine code compliance. This allows architects more flexibility in design and material choice.

How are codes different in Canada?

The NBCC is very similar to that of the U.S. building code in that the primary purpose is life safety. The main difference in my opinion is that the NBCC is structured in a very logical manner making it easier to develop computer programs such as the Code Assessment Engine.

What concerns might this audience have with using systems like the THERMAX™ Wall System? Are the concerns valid or should they reconsider?

Architects and designers want to use the THERMAX™ Wall System because of the energy performance it can deliver. However, the THERMAX Wall System is foam plastic and combustible. They want to know if the THERMAX Wall System meets the fire provisions in the NBCC. This is a valid concern. The CAE delivers a level of confidence.

What steps does using the Code Assessment Engine help architects remove from the design process?

Architects get a chance to decide upon energy efficient wall assemblies that meet the code requirements before engaging a fire consultant. This expedites the initial design stage and potentially provides a broader choice of materials and wall assemblies to meet increasing requirements for energy codes.

Are there any unintended issues that the Code Assessment Engine solves for architects?

Given the Code Assessment Engine has relatively few inputs, it allows architects to experiment with different wall assemblies quickly. This adds clarity and flexibility on the front end of the design process. It also provides an opportunity for those involved in the project, which can include designers, consultants, general contractors, sub-contractors, building officials, competitors, among others, to align on the interpretation or wording of the NBCC. Certainty with code language helps to resolve misunderstanding and doubt, and provides freedom to choose insulation with confidence.