As we know, the Ontario Building Code (OBC) implemented changes to the requirements for Treatment Units as outlined in Article 220.127.116.11. which took effect January 1, 2017. These changes included the removal of Supplementary Standard SB-5 for Approved Treatment Units, and a new reference to the CAN/BNQ 3680-600 standard for certification of treatment units.
In the code change proposals, records of public consultation, and statements previously made by Ministry of Municipal Affairs (MMA) staff and Minister over the last several years, it was very clear that the intent was to make certification to CAN/BNQ 3680-600 mandatory for all treatment units in Ontario, as the new minimum standard. The emphasis was for treatment units that are to be used with smaller final polishing and dispersal options including Shallow Buried Trenches, Type A and Type B Dispersal Beds, or reduced size Filter Beds and Absorption Trenches to be tested rigorously in a cold climate for 12 continuous months with realistic stress conditions.
Recent statements made by staff of the Ministry regarding the language of Article 18.104.22.168. had led to some confusion as to whether certification to the CAN/BNQ 3680-600 standard was mandatory. MMA did state that they believed in the original intent, that certification to CAN/BNQ 3680-600 should be mandatory, however the Code language offered a different interpretation. This interpretation resulted in the need for clarification and guidance from the Ministry to articulate the requirements for treatment units. As a result, the MMA recently issued an Appendix Note (Appendix A-22.214.171.124.), which sets out the testing requirements and documentation that should be provided to the principal authority to demonstrate compliance with Article 126.96.36.199. for any non-certified treatment unit. It is important to understand that a CAN/BNQ certified treatment unit is the clear, straightforward path to compliance with the code. Showing compliance through any other means would be the responsibility of an independent Professional Engineer, providing documentation using the appropriate criteria to be considered by the Principal Authority, similar to the requirements for an Alternative Solution. Ultimately, the Principal Authority carries the full responsibility of verifying compliance criteria, mitigation of risk, and issuance of permits under the Ontario Building Code for their jurisdiction. The Appendix Note provides additional guidance and information to the Principal Authority in this process.