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DEI <br /> DIBBLE ENCINEERS INC <br /> September 25, 2019 <br /> Mr. Jason Schlund I. <br /> Total System Services <br /> I : !j ; II <br /> 8227 44th Ave W, Suite G 1 it q II I ll I' <br /> Mukilteo, WA 98275 � ; I lit I' I''' tl <br /> 1 1 ti <br /> i; t t II, I <br /> Re: Car Toys Everett RTU Replacement 1,111 <br /> DEI Job#: 19-329 <br /> Dear Mr. Schlund: <br /> Dibble Engineers, Inc. (DEI) has completed a review of the new mechanical rooftop unit(RTU) proposed for <br /> installation and the existing roof framing supports at the Car Toys commercial building located at 410 SW Everett <br /> Mall Way in Everett, WA. DEI's scope of review is limited to structural feasibility of the existing building roof framing <br /> to support the new RTU. <br /> The new RTU is a Carrier brand model number 48TCEDO8A2A5. The new unit is proposed to replace an existing <br /> Lennox brand rooftop unit, model number GCS24-953, located at the center of the roof of the building. The new unit <br /> will be located at the same location as the existing unit. The existing unit has a maximum shipping weight of 1060 <br /> pounds with an approximately 40-pound mounting frame. The new proposed unit has a maximum operating weiglht of <br /> 960 pounds and will be installed with a maximum 228-pound curb adapter replacing the existing mounting frame., <br /> The existing unit is currently supported by a 6-3/4"x24"Glulam roof beam. Per our analysis,the increased weigh rid <br /> seismic overturning load on the beam from the new rooftop unit was found to be within a 5 percent di rerce 41 II !l <br /> r <br /> loading from the combined roof and equipment from the existing units. Per the International Existing ilcipg C <br /> (IEBC)2015 Section 707.2 regarding Level 1 Alterations for addition or replacement of equipment: f <br /> 1 1 I '' <br /> "Where addition or replacement of roofing or replacement of equipment results in additional dead loads,li <br /> structural components supporting such reroofing or equipment shall comply with the gravity load <br /> requirements of the International Building Code. <br /> Exceptions: 1. Structural elements where the additional dead load from the roofing or equipment does iigt <br /> increase the force in the element by more than 5 percent." <br /> Per our analysis, the maximum governing bending moment and shear forces on the supporting beam were found to <br /> increase by approximately 0.9 and 0.5 percent respectively due to the new units.As the increase in force in the beam <br /> is less than 5 percent, the IEBC exception listed above applies and no further strengthening or additional roof framing <br /> support will be required. <br /> Dibble Engineers review is limited to the support framing of the rooftop unit as described above. Dibble Engineer did <br /> not conduct a comprehensive building analysis for either vertical or lateral loads. DEI's scope of analysis does not <br /> include the connection of the rooftop unit to the curb adapter,the anchorage of the unit and adapter tb the roof i„ <br /> framing,or the structural integrity of the unit itself. Unless specifically discussed in our review, no other condition I <br /> i1 i 1 , <br /> ll ( tit il ' III111I: t II <br /> DIBBLE ENGINEERS INC 11029 Market Street, Kirkland WA 98033 1425.828.4200 I dibbl .)n:,irlei1 c ,r1 <br /> u <br />