23 212546 ALT

Project Description

The present proposal relates to a multi-use building, primarily made up of residential units. The two (2) proposed sanitary service connections for the project are 150mm connections from the property line to the existing 600mm combined sewer on Soudan Avenue. Upstream of the property line, the 150mm sanitary services connect to separate sanitary manholes. The 150mm sanitary services are smaller than the 300mm sanitary building drains entering the sanitary control manhole from the building. A notice provided by Toronto Building on July 31, 2023 stated that this contradicts OBC 7.4.9.1 (1) "Except as permitted in Sentence (3), no drainage pipe that is of minimum size required by this Part for the purpose for which it is installed shall be so connected as to drain to other drainage pipe of lesser size."The site generates a proposed demand of 14.05 L/s based on the population densities and demands noted in the City's Design Criteria for Sewers and Watermains. Using Manning's formula, a proposed 150mm sanitary building sewer @ 2.0% will have a capacity of 21.65 L/s (see supporting calculations). This calculation demonstrates that the propose 150mm service connection @ 2.0% has capacity to convey the flow from the building drainage systems to the site services. It should also be noted that the 300mm pipe inside the building does not connect directly to the 150mm pipe but connects to a control sanitary control manhole, which will be benched with a channel to transition the larger pipe diameters to the 150mm pipe diameter. In this configuration, the control maintenance hole represent a demarcation point between a building drain drained design under OBC and a service connection design per the MECP guidelines required by Toronto ECS. This presented Alternative Solution is a clarification of these two governing guidelines accompanied by the associated calculations which demonstrate that the proposed design will function properly

Permit Details