Canada will not become a leader in mandating whole building airtightness testing, or at least not in the near-term future. A proposed change to the National Energy Code that could have made the practice compulsory for construction of large commercial, institutional and multi-residential buildings designed to comply with the code’s prescriptive path has now been withdrawn upon instructions from the executive committee of the Canadian Commission on Building and Fire Codes (CCBFC).
The standing committee on energy efficiency (SC-EE) received the decree during a May teleconference as it works on finalizing proposed code changes, which were released for public review and comment earlier this year. “The EC directs SC-EE to revise the proposed changes such that airtightness testing is not mandatory in any compliance path for buildings and houses (NECB and Section 9.36.) at this time,” it states.
The timing might have been opportune for uptake of the measure — provided it was adopted into provincial and territorial building codes — because it would have applied broadly in what is currently Canada’s most buoyant commercial real estate sector. Most newly built light industrial warehouse/distribution facilities adhere to the code’s prescriptive path since there’s rarely a need for developers to take the more complicated performance path involving design and building system trade-offs.
As outlined in last winter’s code change rationale, the CCBFC also calculates warehouses would gain the greatest energy saving benefit from a testing regime to ensure an air leakage rate of no greater than 1.5 litres per second per metre (L/(s.m2)) of 16 modelled commercial, institutional and multi-residential building archetypes — equating to a 31.4 per cent annual average saving across six Canadian climate zones when compared to a baseline of 4.2 L/(s.m2). However, the CCBFC foresees potential energy savings and associated emissions reductions for all building types, which must be found in order to hit Canada’s target to cut greenhouse gas emissions by 30 per cent below 2005 levels by 2030 and to achieve the associated goal for all new buildings to be net-zero-energy-ready (NZER) by the same year. It’s anticipated the pending 2020 version of the code will still highlight airtightness testing as an encouraged optional measure.
“In regard to how the requirement could affect and improve building performance moving forward, I think it’s a step in the right direction,” says Mike Rekker, a project manager with Tacoma Engineers Inc. and chair of the Ontario Building Envelope Council’s (OBEC) codes and standards committee. “Looking at some of the goals that were put in place 10 or 15 years ago for where we wanted to be energy-efficiency wise, I wonder if it has taken a little too long to get to this point.”
“We see that airtightness testing has an added value for the public for the comfort of space and its reduced energy consumption, not only to improve on the impact of climate change,” concurs OBEC president Ehab Naim Ibrahim, research and development manager with Gamma North America. “If I receive a new-built building that suffers from drafts, I will be suffering as an investor, as an owner, as a business occupying that building.”
Sealing leaks saves energy and heating/cooling costs
The proposed change would have been a step up from the existing code provision that requires various building assemblies and components to meet minimum airtightness standards. The CCBFC’s code change rationale notes that air seldom leaks problematically from within those individual elements, but rather at the junctures where those elements adjoin with others. When warmer or cooler air, depending on the season, vacates a heated or cooled space, HVAC systems must then respond.
“Various studies have indicated that air leakage could account for up to 30 to 40 per cent of the total energy used to condition the infiltrated air for the building,” the rationale states. “The key to reducing the air leakage of the building envelope is for the worker to properly seal the connections between materials, between assemblies and between the planes of airtightness and penetrations and terminations. A visual inspection does not provide information as to whether these connections are properly sealed or leak air.”
To carry out whole building airtightness testing, trained technicians literally blow air through to measure where and to what degree it escapes. The proposed code change also references the standard, ASTM E-3158, for how that should be done.
Naim Ibrahim recommends three separate airtightness tests during construction: when the building envelope is first enclosed, or typically at about 40 per cent completion; at 80 per cent completion; and at substantial performance. In particular, he sees the first test as key to identifying issues when it is still relatively easy to correct them.
“If you have a minimum threshold that you are going for, if you don’t meet that, you go back and reseal your building,” he advises.
Rekker hypothesizes that a mandated threshold of 1.5 L/(s.m2) tied to airtightness testing would inspire greater focus on workmanship at this stage. “It could be easier, and in your best interest, to pay attention the first time and do things right,” he says.
For low-rise commercial buildings up to three storeys, the CCBFC’s code change rationale pegs the cost of testing in the range of $500 to $5,000, while it could be up to $50,000 for very large complicated buildings. In both scenarios, energy savings are expected to provide a quick payback.
That would be realized through reduction of winter heating and summer cooling costs, albeit with a slight countervailing diminution of the cooling effect of summer’s nighttime and early morning air. Modelling of the 1.5 L/(s.m2) air leakage threshold against a baseline of 4.2 L/(s.m2) revealed a 9 per cent average annual energy saving for the large office building archetype across six Canadian climate zones, a 5.1 per cent average annual saving for the high-rise apartment building and a 10.1 per cent average annual saving for the primary school.
Challenges for implementation and code adoption
Over the course of conducting airtightness tests in 26 commercial buildings on behalf of Manitoba Hydro, the Sustainable Infrastructure Research Group, based at Winnipeg’s Red River College, offered some observations on the “nuts and bolts” of the exercise in its final report from June 2015. Among the logistical challenges, it cites environmental conditions, such as wind intensity or outdoor temperatures, which can constrain when testing can occur. From the vantage point of Manitoba in 2012-2014, it also suggests there might not be a lot of competition in the marketplace for buildings owners seeking service providers.
“Based on our experiences, the testing of large, commercial buildings as a sole source of revenue is not, at present, a viable business opportunity in Manitoba. The capital outlay is high, staffing requirements dictate a diverse set of skills and the market for such services is fairly limited at present,” the report concludes.
Looking to Ontario in 2020, Naim Ibrahim paints a different picture. “Consultants and labs compete in a low range of fees to do these tests. It’s readily available,” he submits.
Much of Canada embarked on COVID-19’s work-from-home regime around the time the public comment period for proposed energy code changes ended on March 13. Since then, CCBFC’s code committees have presumably been in their own homes working through the required steps of the code development process. Once the 2020 version is published, the provinces and territories will still have to adopt new measures into their own codes before they can go into force.
This might have been an obstacle to the rollout of whole building airtightness testing in any case. The CCBFC’s recent directions to its standing committee on energy efficiency state: “The EC has confirmed that the Provincial/Territorial Policy Advisory Committee on Codes (PTPACC) does not support mandatory airtightness (blower door) testing at this time.”
Barbara Carss is editor-in-chief of Canadian Property Management.