Important Changes to the NECB 2020
Zaineb Al-Faesly, Technical Advisor, Codes Canada
Video chapters
Video transcript
Introduction
Hi, my name is Zaineb Al-Faesly and I am a Technical Advisor supporting the Canadian Board for Harmonized Construction Codes – also referred to as the CBHCC.
This committee is the federal-provincial-territorial body responsible for developing and maintaining the National Model Codes in Canada.
I am a member of the Codes Canada team at the National Research Council of Canada.
Codes Canada acts as the secretariat to the CBHCC, providing administrative, technical and policy support, including publishing the National Model Codes.
To learn more about code changes and provisions in the National Model Codes, or about Canada’s national model code development system, please visit CBHCC’s website.
This presentation is part of a video series led by the CBHCC on the key technical changes incorporated in the 2020 editions of the National Model Codes.
This presentation will focus on important changes to the National Energy Code of Canada for Buildings 2020, and address topics such as the application of the NECB, the building envelope, the lighting power, HVAC and service water heating, and performance compliance.
Update to NECB application statement
Currently, the National Energy Code of Canada for Buildings (NECB) applies to new buildings only. There is no provision requiring that subsequent alterations to these buildings comply with the NECB. This could lead to the construction of a “shell” building which complies with the NECB, but subsequent interior improvements, such as installation of lighting systems, that do not comply with the NECB, leading to the excessive use of energy in operation with the completed building.
Even if new buildings are built as a “shell” building without interior finishes at the time of the occupancy permit, subsequent interior improvements should comply with the NECB.
The NECB application statement was updated to cover subsequent alterations to and within buildings.
This will ensure that future alterations, tenant fit-ups and improvements to building assemblies, systems, equipment and components comply with the requirements of the NECB.
Airtightness testing
Air leakage in buildings is responsible for 30% to 40% of energy use, so ensuring that the air barrier performs as expected is important to reduce energy costs. Testing of the air barrier is one way to ensure that it is constructed correctly.
The NECB 2017 requirements were limited to air barrier assemblies and did not include testing procedures and performance level for the air barrier system of the whole building.
Unintended air leakage does not result from improper materials or assemblies, but rather through gaps between the interfaces of different opaque building assemblies and components. Therefore, the NECB 2020 introduces optional whole building testing in accordance with the standard ASTM E3158, “Standard Test Method for Measuring the Air Leakage Rate of a Large or Multizone Building.”
Whole building airtightness testing will ensure that the air barrier is performing as designed, leading to reduced energy costs.
Whole building airtightness testing is an optional compliance measure at this time, to allow time for industry and jurisdictions to develop the capability to provide whole building blower door testing services.
The new provisions provide guidance for those who opt for whole building airtightness testing.
Thermal characteristics of fenestration and doors
The performance of the building envelope is a key contributor to the energy performance of the building, and excessive heat loss through fenestration and doors leads to higher energy costs and wasted energy for heating and cooling.
To improve the overall building energy performance, the minimum thermal transmittance values (or U-values) of fenestration and doors are reduced.
This reduction in U-values reduces the loss of energy through windows and doors leading to lower heating and cooling loads for the building, smaller HVAC equipment required, and reduced HVAC capital costs.
Thermal characteristics of opaque building assemblies
Additionally, the minimum thermal transmittance values of opaque building assemblies are reduced to improve the overall building energy performance.
The reduction in U-values of opaque building assemblies reduces the excessive loss of energy, leading to smaller heating and cooling loads for the building, resulting in smaller HVAC equipment capacities and reduced HVAC capital costs.
These capital cost savings are expected to partially offset the incremental building envelope costs due to additional insulation.
Interior lighting power
The lighting power density (LPD) values listed in the NECB 2017 are based on older lighting technologies and are not representative of the more energy-efficient light-emitting diode (LED) technologies and products that are now available. Recent improvements in the performance of LED lamps and luminaires means products on the market are now capable of producing the same amount and quality of light as older technologies while lasting longer, and offering greater controllability and higher efficacy. The useful life of LED technologies in many cases can exceed that of comparable fluorescent technologies. This will lead to increased energy savings and a reduced frequency of lamp replacement.
The NECB 2020 updates minimum interior lighting power density values to reflect current technology.
This provides better alignment of the LPD values with the North American marketplace and reduces energy costs and initial costs for luminaires.
Exterior lighting power
Exterior lighting allowances to be used for building exterior applications were not covered in the NECB 2017. In the absence of any provisions, exterior lighting designs could exceed acceptable limits of lighting power, leading to the excessive use of energy.
The NECB 2020 provides lighting power allowances for building exterior applications.
This will simplify the development of new building exterior lighting designs within the proposed lighting power allowance values.
This change will also reduce energy costs, reduce lighting system maintenance requirements, and reduce the initial costs of luminaires.
HVAC and service water heating (SWH) equipment performance
Requirements and standards for HVAC and service water heating equipment in the NECB 2017 did not align with the current minimum Canadian standards for manufacture and the equipment performance requirements for some HVAC and service water heating equipment that are now commonly used were missing. The inconsistencies could cause compliance difficulties for Code users.
Therefore, the requirements for the performance of HVAC and service water heating equipment has been updated in the NECB 2020 to align with the federal energy efficiency regulations.
As many of the available products in the Canadian marketplace have already met these higher requirements, this update synchronizes the Code requirements with developments of the industry.
Removal of HVAC and service water heating (SWH) trade-off path
The NECB 2017, Part 5 (HVAC) and Part 6 (Service Water Heating) trade-off paths were found to be complex and not used by the industry. This was confirmed by a pilot survey undertaken with consultants, builders, building officials and energy modelers.
As a result, the 2020 edition of the NECB deleted both Part 5 and 6 trade-off paths. Deleting these paths avoids updating the Tables and associated costs each time the prescriptive requirements are updated.
Tiered energy performance compliance
The 2020 edition of the NECB introduces tiered energy performance compliance. This is a departure from the traditional approach of establishing only the minimum acceptable requirements in the National Model Codes.
Tiered energy performance compliance provides a voluntary pathway for regulators who want to go above and beyond the minimum Code requirements.
This will:
- help to progressively increase overall energy efficiency of buildings,
- proactively guide industry to respond to future market demand for high-efficiency solutions, and
- provide a nationally harmonized metric for measuring energy performance improvement.
Tiers are defined in terms of the percent improvement as well as energy consumption of the building. However, for simplicity, we will refer only to energy consumption of the building in this presentation.
The first tier is the same as the base Code, representing the requirements in the 2020 edition of the NECB.
The energy consumption is then reduced by a percentage in successive tiers as shown on the slide. These percentages were selected to approximate the energy-saving targets of market programs.
Tiered energy performance compliance provides predictable future energy performance requirements which are to remain fixed in time.
Different performance tiers allow builders and regulators to choose the performance level that best suits their needs.
Conclusion
This concludes the presentation about important changes to the National Energy Code of Canada for Buildings 2020.
How to get involved
To participate in the code development process, visit the CBHCC’s website to find information about upcoming events and meetings, to submit a code change request, to comment on proposed changes during an open public review, or to volunteer to participate on a code development committee.
How to access the Codes
The National Model Codes are published by the National Research Council of Canada.
Visit Codes Canada publications web page on the NRC’s website to purchase a paper copy of the Codes or to access them in free electronic format
Thank you.