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CaGBC GTA Chapter Presentation: The New Ontario Building Code - Where Are We Headed

Caneta Energy: Code Compliance

Complying with the New Energy Efficiency Requirements of the Ontario Building Code (SB-10)

As of January 1st, 2012 the energy efficiency requirements of the Ontario Building Code have increased significantly.  The Energy Efficiency Supplement, or SB-10, was updated back in June, 2011.  Although sometimes referred to as OBC 2012, this in fact an update to the 2006 code.

Prior to 2012, the energy efficiency requirements of SB-10 were essentially ASHRAE 90.1 2004 with modifications to the envelope insulation requirements.  This could be achieved by either meeting all the individual prescriptive requirements, or by using energy modelling to illustrate that building design achieved the same energy performance as a design meeting all the prescriptive requirements.  In both cases, all mandatory design requirements (minimum pipe insulation, etc.) still need to be met.

In the latest  version of SB-10, the design team now has a choice of 3 paths to show compliance.  These are:

  1. Exceed energy efficiency levels of MNECB by 25% and meet all mandatory MNECB requirements.
  2. Exceed energy efficiency levels of ASHRAE 90.1 - 2010 by 5% and meet all 90.1 mandatory requirements.
  3. Exceed energy efficiency levels of ASHRAE 90.1 - 2010 modified by chapter 2 of SB-10 and meet all 90.1 mandatory requirements.

The first 2 options require a building energy simulation to illustrate that the energy efficiency requirements have been met.  Compliance with the 3rd option can be met by either energy modelling or meeting all the individual prescriptive and mandatory requirements.  However, many of the envelope modifications specified in Chapter 2 of SB-10 are extremely stringent and could be prohibitively expensive in many designs (see Table 1 below).  And, unlike previous versions of the OBC, there are currently no trade-off tools that would allow the design team to trade-off performance between components (for example increase wall insulation to allow a decrease in window performance).  Therefore, pursuing option 1 or option 2 using a building energy model will be the most expedient and cost effective option.

Table 1 is a sample comparison of glazing requirements between the previous version of SB-10 (OBC 2006) and the current version of SB-10 (as of January 1st,2012).  This comparison is for a building using window wall construction (would also apply to curtain wall) for a building located in the Toronto climate zone.  Note that the prescriptive path cannot be used when the percent fenestration exceeds 40%, in which case an energy model is required to pursue either option 1 or 2.

Comparison of Window Wall Prescriptive Requirements for Previous and Current versions of SB-10

Comparison of Window Wall Prescriptive Requirements for Previous and Current versions of SB-10

As seen in the above table, the cost of complying with the prescriptive requirements of option 3 may become prohibitively expensive - far more than the cost of a building energy simulation. 

Energy modelling for code compliance can also be combined with the requirements of a LEED application (EAc1 and EAc2 reference requirements will be different than a code energy model) or the pursuit of incentives from programs such as Ontario Power Authority’s High Performance New Construction Program (HPNC).  As always, the energy model can be used optimize the building’s energy performance and cost during the design stage or after occupancy to ensure the building systems are operating as intended.

Caneta Energy has been performing building energy simulations for incentive programs, LEED applications and code compliance since 1998 and has a compliment of staff intimately familiar with energy modelling.  Please contact us for assistance in complying with the energy efficiency requirements of the Ontario Building Code on you next project.

Schulich School of Business with executive learning centre tower in background
Schulich School of Business – Photo courtesy of Robbie/Young + Wright Architects

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