Experience the Comfort of a BamCore structure
BamCore recently completed a battery of thermal performance tests on two Prime Wall Assemblies (varying only by embodied framing factor with a framing factor of 3.91% and 6.65%) and for comparison a matching 5.5” cavity 2×6 conventional stud wall that would be typically found in California construction (with a framing factor of 28.72%). The tests were conducted at a leading national ISO accredited independent lab using a specially calibrated high-performance hotbox. We tested across both a warm range (50 – 100 degs F) of temperatures and a cold range (0 – 70 degs F) of temperatures. In the warm range, the Prime Wall outperformed in thermal resistance by 80%, while in the cold range the Prime Wall outperformed by 96%. Notably, we use more energy to heat during cold periods than we do to cool during warm periods.
Eliminating the Thermal Bridge. BamCore’s innovative use of super-strong timber bamboo allowed us to design the patented load-bearing Prime Wall system, which can eliminate over 90% of cross-cavity framing members like studs, headers, and posts that are typically present in low-rise construction. These wood, steel or concrete framing elements interrupt the insulation barrier and conduct thermal energy at far higher rates than the insulation, thus becoming thermal bridges. The total amount of framing material in a wall is called the framing factor, and in California ranges from a low of around 25% on a simple single-story building, and up to around 40% in multistory buildings, or in areas with strong wind or seismic activity.
Measuring Thermal Performance. Building scientists measure thermal performance in several ways. Thermal resistance or R is familiar to many people and can measure the performance of a single material (e.g. insulation) or an assembly (e.g. a complete wall). Thermal transmissivity or U most frequently measures the performance of a whole assembly or a whole space. Generally speaking, R and U are reciprocally related.
Energy Efficiency and the California Building Code. The built environment through both construction and operations is the largest single generator of greenhouse gases. To help fight climate change, California and other jurisdictions, are now mandating the minimum energy efficiency of new buildings as part of their building codes. In California, all new buildings require an energy assessment (often called Title 24 analysis) as part of the permitting process. Two alternative approaches can be used for Title 24 compliance. One approach is called the prescriptive approach where each component of the building has a specified minimum performance. The minimum performance of these components is specified separately for each of California’s 16 climate zones. The other approach is called the performance approach, and it uses software analytics to model the combined performance of all the buildings sources and uses of energy. The advantage of the prescriptive approach is that it is simple to understand and apply. The advantage of the performance approach is that it allows the design to trade off certain high and low energy efficiency elements if the overall number doesn’t exceed the specified maximum.
Zero Net Energy (ZNE) Buildings. Since 1978, when California adopted the Energy Efficiency Standards for Residential and Nonresidential Buildings in response to a legislative mandate to reduce California’s energy consumption, the state has been on a progressive path to tighten building energy efficiency with each three-year cycle of the state’s building code. The 2019 building code, which becomes effective for each new building in 2020, completes the progression with the objective of requiring all new residential low rise building to perform at ZNE levels. The CA building code then takes this to completion in 2030 when all commercial buildings (low-rise and high-rise) must also reach ZNE energy performance levels. Zero Net Energy is reached when, over the course of a year, a building generates at least as much energy as it consumes. Practically speaking this means that all new residences will pursue a mix of three tactics to reach ZNE: (1) install ample solar power systems, (2) upgrade the structural building envelope to achieve high performance and (3) upgrade the fenestration (doors and windows) to high-performance levels. Improving fenestration performance is usually the most expensive, so the primary focus is on installing the solar and improving the envelope. BamCore’s super-efficient Prime Wall envelope makes a significant contribution to improving the overall building envelope performance.