Treatment Units Without BNQ Approvals?

On January 1st, 2017, the Ontario Building Code replaced reference to supplementary standard 5, which listed approved treatment units for sewage systems. It was replaced with the new standard CAN/BNQ3680-600, "On-site Residential Wastewater Treatment Technologies." At first it appeared that the only compliance option in the OBC was to ensure all treatment units meet this new standard, however, when reviewing the solution in more detail, there was more than one compliance option available.

When one is seeking compliance for sewage treatment units, one refers to division B, 8.6.2.2.(1). This sentence requires that the unit ensures the effluent does not exceed the maximum concentrations listed in table 8.6.2.2. The BNQ standard is referred to in note (2) of the table but only to clarify that the levels referred to in the table correspond to the standard.

Upon further investigation, sentence (5) of the article indicates that residential treatment units that meet the BNQ standard are deemed to comply with the table. Based on this rationale, the BNQ standard theoretically is another way to comply with the provision, although the table itself is the primary way to meet the OBC. Alternatively, non-residential properties do not have BNQ as a compliance option, so table 8.6.2.2. remains their only option.

As a chief building official, it will require more effort to ensure compliance is met by using only the table. The manufacturer would need to provide sufficient credible data to convince the building official that the levels of treatment have been adequately met. There are manufacturers in Ontario with a vast amount of local data to show that they meet the levels listed in the table. Building officials will likely have different Comfort levels to accept this compliance path based on their experience with the unit manufacturer.

Perhaps future code changes will only refer to the BNQ standard for all residential occupancies. Until then building officials will also have the option of determining compliance based on the table.

Gerald Moore is the president of RSM building Consultants, which provides individualized support services to Municipal Building departments. His background includes over 25 years of experience working with building departments throughout Ontario. RSM provides plans examination Services, alternative solution review, inspection and CBO transition support.