senior energy consultant corporate energy initiatives

147 Alessio Drive, Hamilton, ON. L9B 0E8

(647) 671-8530, [email protected], www.jpsamuel.com July 31, 2018 Ms. Dorothy Chao, LEED AP O+M Senior Energy Consultant Corporate Energy Initiatives, Environment and Energy Division, City of Toronto Metro Hall, 2nd floor, 55 John Street, Toronto M5V 3C6 Dear Dorothy, RE: CITY OF TORONTO –Structural for Net- Metering PV Systems

Preliminary Structural Feasibility Report: Installation of solar PV on the Roof of the Building located at 4330 DUFFERIN STREET, NORTH YORK, TORONTO

Our File No. 2018-JPS-042F Ontario’s Net- Metering Regulation has been in place since 2005, and requires all electricity distributors to offer net metering to customers on request. Under Ontario’s Net- Metering program, customers can generate renewable energy onsite for their own use and receive bill credits for any surplus electricity sent to the grid. Electricity exported to the grid is valued at volumetric electricity rates (for residential customers, currently Tiered Pricing) and credited to the customer’s electricity bill. To take advantage of this opportunity, City of Toronto, has taken the initiative and has retained J.P. Samuel & Associates Inc. to conduct a preliminary layout and structural assessment for suitability under the Net- Metering PV systems program. Your office has requested us to review the installation of 400kW DC solar carport system on the existing multi- storey parking garage for EMS Headquarters located at 4330 Dufferin Street, North York, Toronto - Ontario and our opinion is that maximum number of panels (350W) that can be installed is 1134 (One Thousand One Hundred and Thirty-Four) standard size (1956mm x 992mm x 40mm) solar panels for Solar PV Parking Canopy system. This report is not to be construed as an overall acceptance of the building structure but refers only to our observations made on site. The responsibility for the design of the structure remains with the engineers who originally designed the structure. We did not perform a detailed analysis of the design of the existing roof structure during our review. Further, it is assumed that the contractor constructed the structure in accordance with the structural drawings, revisions and instructions provided by the original design team. The comments made in this report are limited to what we could see from the top and underside of the concrete slab. During our review of the structure, no physical or destructive testing was performed. Comments and conclusions are therefore based on our visual observations only.

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(647) 671-8530, [email protected], www.jpsamuel.com We understand that the proposal entails installing solar panels supported on carport canopy above the upper level parking garage. The canopy consists of a steel frame (beams/ girders) that spans the width of the parking garage and steel purlins to support the solar panel arrays above. The vertical steel columns of the canopy will transfer the loads to load-bearing columns and walls below the upper level parking garage slab. For the building at 4330 Dufferin Street, J.P. Samuel & Associates Inc. has been engaged by City of Toronto to

• Review of structural and architectural drawings, if available • Site visit to confirm as-built dead loads (roofing and suspended loads) • Assess the capacity of the existing roof and/or building structure to support a ballasted PV system • Estimate the maximum number of solar panels that the roof can safely support for ballasted

system. Please use the following PV panel characteristics: Dimensions (L x W x D) 1956 x 992 x 40 mm (77 x 39 x 1.6 inch) Weight 21 kg (46.3 lbs) Landscape/ Portrait assembly

• Preliminary structural feasibility report under Professional Engineer's seal confirming the structural capacity of the existing structures to safely support the recommended solution and system size for the solar PV system.

Please note that the scope of the services of J.P. Samuel & Associates Inc. is not to analyse the individual components of the roof structure, but to initially assess the overall capacity of the roof framing to determine whether the original design offers the possibility of reserve loading capacity that would allow the City to proceed further with considering the installation of a roof mounted solar PV system. A brief walk- through of the building was conducted on June 13, 2018. The proposed solar PV parking canopy system will be installed above the upper level of the parking garage. The garage upper level consists of 230mm thick flat concrete slab with 2800x2300x100 drop panels and 250 capitals supported on concrete columns. Upper Level- Parking Garage: We were able to obtain existing structural drawings of 1992. The drawings provided by your office and that we reviewed are: Drawing No. DAS-108.92 S1 Parking Garage- Foundation Plan dated June. 30, 1992 Drawing No. DAS-108.92 S2 Parking Garage- Roof Framing Plan dated June. 30, 1992 As noted in the existing drawings, parking garage- upper level flat slab is designed for following service loads: Dead Load = 6.50 kN/m2 Live Load = 6.00 kN/m2. As this structure was designed in 1992, the structural components have to be analysed and/or designed to meet or exceed the requirements of the current 2012 Ontario Building Code. This report will concentrate on assessing whether there appears to be reserve capacity in the design loads.



(647) 671-8530, [email protected], www.jpsamuel.com The current design requirements for buildings in the province of Ontario are stipulated in the 2012 Ontario Building Code (OBC). In general, it is not necessary to re-analyse buildings each time a new Building Code is released, however, when the loading conditions on an existing building are knowingly altered, it is necessary to perform a structural evaluation and possible upgrading of the structure to support the new loading conditions. Many changes have occurred in the building code since inception. The two (2) key changes applicable to this report are the basic roof snow loads, and the introduction of Importance factor which is applied to the climatic loads, the value of which is dependent on the Importance Category of the building. Importance Categories are: Low, Normal, High and Post-disaster, and are more fully explained in Table 4.1.2.1.B of the OBC. This building would be considered to be in the “Normal” importance category. With respect to the basic roof snow loads, the 2012 Ontario Building Code recommends a design snow load of 1.36kPa for North York area in Toronto and for a Normal importance category building and minimum specified live load of 6.0kPa for Garages with vehicles exceeding 4000kg but not exceeding 9000kg gross weight. Since there is no capacity available for the roof slabs, we analysed the option of installing canopy system where the loads will be directly transferred to the concrete columns and load bearing walls below. Our analysis indicates that the concrete columns/walls and footings below have additional capacity to support the Solar PV Parking Canopy. The new parking canopy roof structure will be designed for dead load and basic roof snow load. The Ontario Building Code- 2012 recommends a design roof snow load of S=1.0 (1.20x0.80x1.0x1.0x1.0 + 0.40) = 1.36kPa for North York area. (Ss= 1.20kPa, Sr = 0.40kPa, Cb= 0.8, Cs= 1, Cw= 1, Is= 1, Normal Importance Category) The solar panel field above the canopy would cover approximately 95% of the roof area. The roof is approximately 150m x 19m and roof structure would consist of sub- frames (purlins) to support solar panels. The new canopy roof will have a slope of 10 degrees, with lowest end of the canopy at 4.0m from the slab level. City of Toronto has four options to install the Solar PV Parking Canopy:

1. Steel framed assembly with steel columns on each side installed directly above the concrete columns that support the upper level garage slab. There will be a girder beam spanning the width of the parking lot between each pair of steel columns, cantilevering either side (See Sketch- 03 & 04). The disadvantage of having such a system is that the sizes of structural steel used for the framing the canopy system will be larger in comparison to the other options mentioned below.

2. Steel framed assembly with steel columns on each side installed directly above the concrete columns that support the upper level garage slab. There will be an additional steel column (south side) supported by the concrete load bearing wall below (See Sketch- 05 & 06) to reduce the overall steel quantity required.

3. Steel framed assembly with steel columns on each side installed directly above the concrete columns that support the upper level garage slab. There will be two additional steel columns (one on each end of the girder beam) above the concrete load bearing wall below (See Sketch- 07 & 08) to further reduce the overall steel quantity required.



(647) 671-8530, [email protected], www.jpsamuel.com

4. The options mentioned above, will affect five parking spaces. In order to prevent obstruction to the parking spaces, the steel frame assembly with steel columns can be installed in-line with the existing parking space markings. If this requires any steel columns to be supported by the structural slab rather than the concrete column, new steel beams will be required beneath the slab to act as additional reinforcement. The new steel beams will be connected to the adjacent concrete columns below the capitals while maintaining allowable headroom (See Sketch- 09 & 10). The new steel beams below for the carport steel columns shall be W310x86 (The steel beams and connections may vary with carport frame design) spanning between the concrete columns.

Snow Melting System: Installing the proposed solar panels will result in an unobstructed, smooth and slippery roof surface and the probability of snow sliding increases. Proper maintenance of the gutter/ eaves trough and danger of the snow sliding off to the pavement below shall be considered by the building owner of the building. Based on an assumed snow density of 3kN/m3 (medium density snow), we urge that the snow not be permitted to slide off from the roof structure. We recommend to install a snow melting system and a new gutter/eaves trough near the edges that would prevent any possible snow sliding off to the driveway below. Design Storm Drainage System: Existing roof drains should also be regularly monitored to ensure that they are free flowing and that they do not allow water or ice to accumulate around them. We recommend a storm drainage system designed and stamped by a Professional Engineer for the new inflow of melted snow or rain water from the canopy roof structure to prevent any water retention.

Summary: Since the additional dead load is negligible compared to the total original design dead loads, the installation of new solar equipment will not affect the original design earthquake forces, as the earthquake forces are directly related to the weight of the building. All racking construction above the carport canopy shall be reviewed and stamped by a Professional Engineer and shall be designed to withstand Toronto climatic wind, snow and rain loads as per applicable municipal and provincial building codes. Materials shall be designed for long life outdoors such as aluminium, galvanized steel or stainless steel. Care shall be taken to ensure no detrimental effects to the underlying roof structure. The designer shall review all structural drawings supplied by the City of Toronto. One of the primary considerations of roof mounting of solar panels is the wind loading — often referred to as the active or uplifting load. As the height of the solar panels above the roof increases the wind loading also increases. Furthermore, the solar panel system is anchored to the roof framing system. The wind resistance to the system is provided by the roof anchoring. A building permit will be required prior to construction. A Professional Engineer proficient in structural issues must review all mounting designs to ensure compliance with the requirements of the current Ontario Building Code.



(647) 671-8530, [email protected], www.jpsamuel.com Attached to our report is the preliminary solar panel layout. Should you require further clarification, please do not hesitate to call our office. Regards, J.P. Samuel & Associates Inc.

James Samuel, P. Eng.




Satellite Image (Parking Canopy Area)

Existing Garage Parking- Upper Level

Solar PV Parking Canopy Area




Existing Garage Parking- Upper Level Slab

Existing Garage Parking- Upper Level Slab


SOLAR PANELS,1134 Nos.

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147 Alessio Drive, Hamilton, Ontario, L9B 0E8Tel:(416) 616-0196 email: [email protected]

www.jpsamuel.com

NEW SOLAR PV PARKING CANOPYPROJECT PRELIMINARY STRUCTURALASSESSMENT

SOLAR PV PARKING CANOPY& UPPER PARKING LEVELLAYOUT FOR OPTIONS 1,2,&3

ENVIRONMENTAL &ENERGY DIVISIONMETRO HALL, 2NDFLOOR, SUITE 211, 55JOHN ST. TORONTO, ON.M5V 3C6

4330 DUFFERIN ST.TORONTO, ON M3H 5R9

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