The Energy Efficiency section of the BC Building Code got a makeover back in May 2023. One of the big announcements was the introduction of the “Zero Carbon Step Code”. This piece will hopefully clarify a few things that are not particularly obvious, such as “zero” not meaning zero and the fact that there are no “steps”.
The Zero Carbon Step Code is a new tool to align with the CleanBC Roadmap to 2030 goal that:
“By 2030, all new buildings will be zero carbon, and all new space and water heating equipment will meet the highest standards for efficiency.”
Note, this piece is about Part 3 buildings (larger, complex buildings), not Part 9 buildings (single family homes).
Intent
The Zero Carbon Step Code is a tool for local governments to encourage or require lower emissions in new buildings. Each individual authority having jurisdiction (AHJ) can reference the Zero Carbon Step Code in bylaws and programs to require or encourage lower carbon new construction in their communities. It is currently voluntary. That means each AHJ has the option to adopt the Zero Carbon Step Code or not.
Background
The Zero Carbon Step Code is essentially an addition to the existing Energy Step Code, which many people are likely familiar with (if not, click on the links on each metric to learn more). The BC Energy Step Code uses two energy efficiency metrics: TEDI and TEUI. It sets limits, which vary by building type, using these two metrics. There are four levels. Each level is called a “step” which gives the name to the Step Code. The limits get more stringent as the levels increase, with Step 4 having the most difficult limits to achieve.
The Energy Step Code was established to enhance energy efficiency in new construction while the focus of the Zero Carbon Step Code is emissions reductions. The two are intended to be used in combination to enhance energy efficiency and reduce emission reductions for new buildings. The voluntary nature of the Zero Carbon Step Code is similar to how the Energy Step Code was first introduced in 2017 on an opt-in basis. The Energy Step Code has since gone on to become a mandatory requirement within the BC Building Code for all applicable new buildings.
The Zero Carbon Step Code is similar in format to the Energy Step Code. This is demonstrated by the similarity of the tables below which are populated with information from the relevant BC Building Code tables.
Energy Step Code limits for Climate Zone 4. BCBC – Division B – Tables 10.2.3.3 G-J. Units: kWh/(m2.year)
Zero Carbon Step Code limits. BCBC – Division B – Tables 10.3.1.3. Units: kgCO2/(m2.year).
Definition
The BC Building Code defines many terms. Zero Carbon Step Code is not one of them. In fact, the term never actually appears in the BC Building Code. It is understood to refer to Division B – Acceptable Solutions > Part 10 – Energy Efficiency > Section 10.3 – Greenhouse Gas Emissions.
Step Code sections of BC Building Code – Division B – Part 10 – Energy Efficiency
Section 10.3 was introduced as an entirely new section of the BC Building Code in May 2023. The metric GHGI was introduced. It is a metric already in use by the City of Vancouver and will be familiar to many people in the industry. In practice, Section 10.3 is primarily a table that sets limits using the GHGI metric.
Like the Energy Step Code that came before, there are four levels which get more stringent as they increase. These again vary by building type and, instead of using TEDI and TEUI, use the GHGI metric. The limits do not vary based on climate zone as is the case for the Energy Step Code, where colder locations have higher limits.
Steps (or Levels?)
Confusingly, despite what the name might suggest, the Zero Carbon Step Code does not actually use “steps”. It instead uses GHG Emission Levels, which are abbreviated as EL-1 through EL-4. Despite the confusing naming, it effectively has “steps” and functions in the same manner as the Energy Step Code, it just uses the word level instead of step.
There have been terms associated with each of the four emission levels which are used in communication material but not defined within the BC Building Code. Only the lowest level, “Measure Only”, is defined. The other terms of “Moderate”, “Strong”, and “Zero”, which are all followed by the term “Carbon Performance” are not. The following graphic shows the emission level (EL) from the BC Building Code being referred to along side the terms used in communication material surrounding the Zero Carbon Step Code.
Zero Carbon Step Code terms and the associated emission levels per the BC Building Code
While “Moderate” and “Strong” are unquantifiable words, “Zero” is quantified by definition. However, the term “Zero” in the Zero Carbon Step Code case does not actually mean zero. EL-4, which the term “Zero Carbon Performance” is associated with, has a value greater than zero (1.5-2.0 kgCO2/(m2.year) depending on building type). This has been explained in communication materials as being because, although the BC electricity grid is very low emissions, it is not yet zero, but the province has proposed a 100% Clean Electricity Delivery Standard for the BC Hydro grid, and once that is in place, zero will really mean zero.
EL-1 or “measure only” does not have a GHGI limit as is the case for the higher levels. Nor does anything have to be measured, even though the term may suggest that emissions would actually be measured in some way during operation. It simply means the GHGI needs to be calculated and reported based on the design of the building. This again is similar to how the Energy Step Code is a performance limit based on design and is not followed through to a measuring of performance during operation.
In Practice
As previously mentioned, Section 10.3 is primarily a table that sets limits using the GHGI metric. Depending on the emission level adopted by an AHJ and the building type, the relevant GHGI limit can be established. Below is a direct copy from the BC Building Code of the table that is effectively the Zero Carbon Step Code.
GHG Emission Levels by building type / occupancy classification per the BC Building Code
The most common use for the GHGI limits is to demonstrate a new building is designed in compliance with requirements under the building code at building permit stage. However, this is likely to be reference by other standards and incentive programs as is the case with the Energy Step Code under Clean BC funding, Fortis BC incentives, CMHC financing. Whenever compliance with a GHGI limit needs to be demonstrated, an energy modelling / building performance simulation is used. How to calculate the GHGI of a building is explained in this dedicated article.
Early Adopters
As mentioned above, the Zero Carbon Step Code is optional. There are AHJs who have already adopted it, including some who have jumped straight to the upper levels with the most stringent GHGI limits. Early adopters include the City of Nanaimo, the City of North Vancouver, and the City of Victoria.
Adoption timeline for EL-4 by the District of Saanich and the City if Victoria of the Zero Carbon Step Code as an example of early adopters
Requirements by Location
Unfortunately, there is no centralized place to track which AHJs have adopted the Zero Carbon Step Code, or the level required in different locations. This is an issue in terms of clarity on the different requirements in different locations. Determining requirements requires checking the requirements of individual AHJs. This is often available on dedicated web pages or through documents such as council meeting minutes but may require directly contacting AHJs when information is unavailable or unclear.
The issue of clarity around requirements for individual AHJs is not helped by the lack of a clear formalized process for AHJs to adopt the Zero Carbon Step Code, how this is to be communicated, or an established notice period. The result is that AHJs can seemingly adopt it as they see fit which may result in project teams needing to react to targets changing midstream.
Scope
The Zero Carbon Step Code only deals with the carbon associated with the energy used to operate a building once it is occupied. The embodied carbon associated with the construction of the building is not covered.
It regulates only primary space-heating equipment. Secondary heating systems are exempted. Wood-burning stoves and decorative fireplaces that are not the primary space-heating equipment are exempted.
It only regulates indoor equipment. It does not restrict outdoor grills, heated driveways, nor pools.
Summary
The Zero Carbon Step Code introduces a GHGI limit for new buildings to the BC Building Code. This metric will be an effective tool in reducing the operational emissions of new buildings moving forward. The communication and language around the metric will likely cause confusion, such as the communication that “Zero” does not mean zero, but it will mean zero in the future. It will take some time for industry to get familiar with the changes and how to design new buildings to meet required limits. Until then, there will be some surprises for developers to navigate, including cost increases, particularly in locations where AHJs are early adopters of high levels of the Zero Carbon Step Code.
Sources
Much of the information within this article has been taken from the Government of British Columbia’s main website and the dedicated website for the Step Code. The most relevant sources referenced are the news article Building code changes support B.C.’s zero-carbon targets and Step Code Implementation Tools, more specifically the Zero Carbon Step Code presentation.
For anyone unfamiliar with the Step Code entirely, these three articles, recommended to read in this order, can get you up to speed: