A major portion of the engineering design that is associated with the construction of industrial and commercial type buildings is completed under the well-defined scope of the Ontario Building Code. Typically the building design along with its mechanical and electrical components is reviewed by the local municipal building department to ensure conformity with the OBC.
The engineering external to the building envelope such as site servicing, grading and stormwater management is normally reviewed by multiple approving authorities and can often result in conflicting requirements. Depending on geographical location, a site servicing and stormwater management design could be reviewed by both the building department and planning department of the local municipality, the local conservation authority, the Ministry of the Environment and the Ministry of Transportation, and it is not uncommon to receive conflicting comments from these authorities. As an example, the City of Toronto’s Development and Planning Department requires an orifice tube to control post development flows from a site to be located on the private side of the development, while the Ministry of Transportation requires an orifice tube to be installed within the public right of way. In the same instance, a municipal Building Department may indicate that a small diameter sewer downstream of a larger sewer is contrary to the Building Code.
There are also instances where technical review staff within the same municipality interpret and apply municipal guidelines differently.
Further complications arise when municipal staff applies blanket policies to a unique site specific issue. MGM Consulting recently provided a site servicing design and proposed to re-use the existing services within the boulevard. A video of the existing services indicated that the sewers were clean and structurally sound and were at an adequate depth to service the development. The policy within that particular municipality requires the owner to replace the existing service connections within the municipal right of way independent of their condition or value. The policy imposed was not based on engineering principles but rather political principles.
Addressing contradicting comments and the interpretation of municipal guidelines often includes educating the review agencies or presenting the design in a manner that will satisfy technical review staff. For example, labeling an orifice tube as a 100mm storm sewer could give the review staff the comfort level to approve a particular design.
Addressing policy issues is often more challenging. The role of the servicing engineer is to advise the architect of the issues and associated costs so the owner can make an informed decision as to whether or not it is worth addressing at a political level.
The above issues illustrate how the approval process is very fluid and sometimes difficult to navigate. Experienced site servicing engineers will approach a design recognizing the shortcomings of the approval process early in the process so that the client can be aware of the impacts on costs and schedule. More often than not, this early recognition helps to expedite the Site Plan Approvals that are typically critical to the project schedule.
For additional information on this topic, contact MGM directly.