Proposed Change 1527
From: National Research Council Canada
188.8.131.52.Application of Parts 1 to
184.108.40.206.Prescriptive, Trade-off or Performance Compliance
Note A-220.127.116.11. NECB Compliance Options.
In order to prepare industry for increasingly stringent energy efficiency codes in the future, and acclimate industry to the use of performance modeling solutions as a comprehensive compliance methodology, introducing tiered code metrics to the code will offer increased flexibility to authorities having jurisdiction (AHJ).
Any delay in the development of tiered energy efficiency requirements would likely impact industry and jurisdictions who are waiting for the national code process to develop requirements meeting the goals set out in the Pan-Canadian Framework. This may favor jurisdictions developing their own requirements and not adopting the national codes, increasing the likelihood of less harmonization for requirement applications between jurisdictions across the country with potential detrimental impact to the construction market and the industry.
Justification - Explanation
Adopting a tiered energy code will ensure that some national consistency in stretch targets may be instituted, as well as offering a common metric for measuring performance increases within buildings beyond minimal compliance./ Furthermore, it will promote more progressive energy code adoption through the establishment of common thresholds for comparative data analysis
Inclusion of tiered energy codes will reduce the burden on individual Authority Having Jurisdiction (AHJ) in establishing reach targets and provide common metrics for national programs and targets. As Tier 1 requirements are the same as the balance of the NECB there is no cost impact or energy savings attributed to this Tier. Progressive Tiers were selected to improve efficiency levels, leading to a top tier which is equivalent to net zero energy ready performance. While Tier 4 was originally set at 25% of the building energy target (reference building), the modelling rules, non-regulated loads, and fixed loads, made this target near impossible to achieve for several building typologies. As a result, the Tier was increased to 40%, for the 2020 code, to enable progressive designs to achieve Tier 4 irrespective of the noted modelling limitations. It should also be noted that all the tiers are voluntary until they have been adopted into legislation by a province or territory (AHJ). In that sense, the tiers represent voluntary standards that have been codified. It is up to the AHJ to decide whether to adopt a tier or not. The publication of these voluntary tiers in the code should help industry and the public prepare for potential upcoming code changes, essentially ‘priming’ the market for upcoming code cycles.
The NRC report (Simulation Study for WG-Costing – PCF1527 Impact Analysis) details solutions and associated costs with achieving the Tiers energy performance based on a reference of NECB 2017 (as the 2020 code is not available). For this study an energy simulation analysis was undertaken to demonstrate the technical feasibility of the Tiers and estimate the cost increments. The analysis focused on six archetype buildings in six locations (each location is a representative city for each of the climate zones). An engineering approach was taken whereby the models were analyzed and the principle contributors to energy use were addressed (e.g. if heat loss through the envelope was dominating the energy consumption the wall insulation levels, window performance and air-tightness were improved and the efficacy of these changes evaluated).
The simulation results show that Tier 2-4 energy performance levels are achievable using current technology (see Figures 1, 2, and 3). The analysis also shows that the Tier 4 targets generally meet or exceed ASHRAE targets for net zero energy performance. This shows that although the NECB performance path is based on a relative performance criteria for demonstrating compliance (i.e. reference vs proposed) the resulting Tier 4 targets are in-line with industry best practice.
Figure 1. Tier 2 Compliant Archetype Energy Reductions.
Figure 2. Tier 3 Compliant Archetype Energy Reductions.
Figure 3. Tier 4 Compliant Archetype Energy Reductions.
The costing analysis (envelope, lighting and HVAC) for the identified solutions for each Tier was sub-contracted to a cost consultant (Hanscomb Quantity Surveyors). The costing analysis results for Tier 2 and 3 for Edmonton are shown in Table 1 (Tier 4 is only shown for comparative purposes). To calculate the Tier 2 and Tier 3 costs in other locations, the factors presented in Table 2 can be used. For Tier 4, five locations were fully costed and the results presented in Table 3, as the total cost (envelope, lighting, and HVAC) in $/m2 floor area; the incremental cost of Tier 4 relative to NECB 2017 are presented in Table 4.
The results show the medium and large offices and a few other archetypes have a lower cost at higher Tiers compared to NECB 2017 (e.g. for Tier 4, see Table 4’s bolded cost increments). This is attributed to the decrease in window area (reduced window-wall ratios; no skylights) and reduced HVAC capacities (more efficient envelope and HVAC reduces coil capacities/air flows, and results in smaller duct and equipment sizes). This use of more efficient HVAC systems further reduced costs. A more comprehensive and detailed analysis will be required to fully understand these differences.
These results are consistent with other studies, e.g. CaGBC’s report on “Making The Case For Building To Zero Carbon”. In these cases the increased costs for some components are offset with significant reductions elsewhere.
Table 1. Baseline, Tier 2, 3, and 4 Total Cost per Floor Area (envelope, lighting and HVAC cost) ($/m2) – Edmonton.
|Archetype||NECB 2017||Tier 2||Tier 3||Tier 4|
|Retail Strip mall||$1,240||$1,292||$1,256||$1,310|
Table 2. Location Cost Factors (Tier 2 and Tier 3 only).
Table 3. Tier 4 Area Normalized Total Cost ($/m2 floor area) – 5 locations.
|Retail Strip mall||$1,235||$1,177||$1,188||$1,310||$1,462|
Table 4. Total Cost Increments Compared to NECB 2017 ($/m2 floor area) - 5 locations.
|Retail Strip Mall||$78||$4||$60||$70||-$7|
From previous cost analyses for codes adoption (e.g. British Columbia Step Code) it should be noted that multiple solutions exist for each performance solution each with a unique cost. Thus there may be less expensive solutions and more expensive solutions to achieve the Tier 2 and 3 targets.
Additional documentation for this proposed change is available on request at Codes.Publicreview@nrc-cnrc.gc.ca.
Tiered energy codes are voluntary, eliminating any mandated burden beyond the policy objectives of individual AHJ’s which are enabled through current code adoption processes. Additionally, by utilizing existing NECB Part 8 procedures in calculating the reduction percentages (improvements?), there is no additional burden placed on the applicant or AHJ. Therefore, there are no enforcement implications beyond those already found in the NECB.
Who is affected
Designers, engineers, architects, building officials and manufacturers/suppliers.