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OBSERVED CONDITIONS: <br />CONCLUSIONS: <br />LIMITATIONS: <br />Praneet R Erusu, P.E. <br />Principal Engineer <br />Erusu Consultants US Inc. <br />The observed roof framing is described below. If field conditions differ, the contractor shall notify the engineer <br />prior to starting construction. The roof framing is supported by 2x6 Rafters @ 24" O.C are spanning between <br />load bearing walls. The maximum allowed clear span of rafter is 12ft, to be verified in field by the contractor. <br />Based upon our review, we conclude that the existing structure is adequate to support the proposed solar panel <br />installation. In the area of the solar array, other live loads will not be present or will be greatly reduced (2019 CBC, <br />Section 1607.13.5). The gravity loads and the stresses of the structural elements, in the area of the solar array are <br />either decreased or increased by no more than 5%. Therefore, the requirements of Section 503.3 of the 2019 <br />CEBC are met and the structure is permitted to remain unaltered. <br />The solar array will be flush-mounted (no more than 6" above the roof surface) and parallel to the roof surface. <br />Thus, we conclude that any additional wind loading on the structure related to the addition of the proposed solar <br />array is negligible. The attached calculations verify the capacity of the connections of the solar array to the existing <br />roof against wind (uplift), the governing load case. Regarding seismic loads, we conclude that any additional forces <br />will be small. Conservatively neglecting the weight of existing wall materials, the installation of the solar panels <br />represents an increase in the total weight (and resulting seismic load) of 2.8%. Because the increase in lateral <br />forces is less than 10%, this addition meets the requirements of the exception in Section 503.4 of the 2019 CEBC. <br />Thus the existing lateral force resisting system is permitted to remain unaltered. <br />Installation of the solar panels must be performed in accordance with manufacturer recommendations. All work <br />performed must be in accordance with accepted industry-wide methods and applicable safety standards. Existing <br />Roof and structural members are assumed to be in good and serviceable condition. The contractor must notify <br />Erusu Consultants US Inc. should any damage, deterioration or discrepancies between the as-built condition of <br />the structure and the condition described in this letter be found. The use of solar panel support span tables <br />provided by others are allowed only where the building type, site conditions, site-specific design parameters, and <br />solar panel configuration match the description of the span tables. The design of the solar panel racking (mounts, <br />rails, etc.) and electrical engineering is the responsibility of others. Waterproofing around the roof penetrations is <br />the responsibility of others. Erusu Consultants US Inc. assumes no responsibility for improper installation of the <br />solar array. <br />13 Dec 2022 <br />EXP : 30 Sep 2023 <br />3510 S Woodland <br />Pl02/10/23