Transient effects

[rd2]

By adjusting traditional insulation layer thickness (and possibly conductivity if needed), as per ISO 10211 & RP-1365 methodologies, TBD does not significantly alter a construction's transient thermal response, à la RP-1145. This is described in a bit more detail in the last paragraph here. The current approach is deemed suitable/acceptable for well-insulated assemblies in cold climates, but decreasingly so in warmer climates and/or with less insulation.

The "equivalent wall" approach (example here) is a practical solution that - in principle - could be harnessed to solve the issue. However, it requires a priori knowledge - through physical testing or 2D (or 3D) numerical approximations - of a construction's transient response while factoring-in known thermal bridges. This may be feasible for minor thermal bridging (i.e. clear-field R-values), but appears somewhat impractical when considering major thermal bridging (i.e. what TBD tracks), given its surface-specific nature (i.e. unique geometry). In a nutshell, it would be interesting to investigate how to generalize the "equivalent wall" approach without a priori testing or 2D/3D simulations results.