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SolarMount Unirac Code-Compliant Installation Manual :i:UN I RAC Part I. Procedure to Determine the Design Wind Load [1.1.] Using the Simplified Method - ASCE 7-05 The procedure to determine Design Wind Load is specified by the American Society of Civil Engineers and referenced in the International Building Code 2009. For purposes of this document, the values, equations and procedures used in this document reference ASCE 7-05, Minimum Design Loads for Buildings and Other Structures. Please refer to ASCE 7-05 if you have any questions about the definitions orprocedures presented in this manual. Unirac uses Method 1, the Simplified Method, for calculating the Design Wind Load for pressures on components and cladding in this document. The method described in this document is valid for flush, no tilt, SolarMount Series applications on either roofs or walls. Flush is defined as panels parallel to the surface (or with no more than 3" difference between ends of assembly) with no more than 10" space between the roof surface, and the bottom of the PV panels. This method is not approved for open structure calculations. Applications ofthese procedures is subject to thefollowing ASCE 7-05 limitations: 1. The building height must be less than 60 feet, h < 60. See note for determining h in the next section. For installations on structures greater than 60 feet, contact your local Unirac Distributor. 2. The building must be enclosed, not an open or partially enclosed structure, for example a carport. 3. The building is regular shaped with no unusual geometrical irregularity in spatial form, for example a geodesic dome. 4. The building is not in an extreme geographic location such as a narrow canyon or steep cliff. 5. The building has a flat or gable roof with a pitch less than 45 degrees or a hip roof with a pitch less than 27 degrees. 6. If your installation does not conform to these requirements please contact your local Unirac distributor or a local professional engineer. If your installation is outside the United States or does not meet all of these limitations, consult a local professional engineer or your local building authority. Consult ASCE 7-05 for more clarification on the use of Method I. Lower design wind loads may be obtained by applying Method II from ASCE 7-05. Consult with a licensed engineer if you want to use Method II procedures. The equation for determining the Design Wind Load for components and cladding is: pnet (psf) = AKzd pnet3O pnet (Pd) = Design Wind Load X = adjustmentfactorfor building height and exposure category Kzt = Topographic Factor at mean roof height, h (ft) I = Importance Factor pnet30 (Psf) = net designwind pressurefor Exposure B, at height = 30feet, I = 1.0 You will also need to know the following information: Basic Wind Speed = V (mph), the largest 3 second gust of wind in the last 50 years. h (ft) = total roof heightfor.flat roof buildings or mean roofheight for pitched roof buildings RoofPitch (degrees) This manual will help you determine: Effective Wind Area (sf) = minimum total continuous area of modules being installed (Step 2) Roof Zone = the area of the roof you are installing the pv system according to Step 3. RoofZone Dimension = a (ft) (Step 3) Exposure Category (Step 6) [1.2.] Procedure to Calculate Total Design Wind The procedure for determining the Design Wind Load can be broken into steps that include looking up several values in different tables. Table 5 has been provided as a worksheet for the following 9 steps (page 8) Step 1: Determine Basic Wind Speed, V (mph) Determine the Basic Wind Speed, VOMph) by consulting your local building department or locating your installation on the maps in Figure 1, page 4. Step 2: Determining Effective Wind Area Determine the smallest area of continuous modules you will be installing. This is the smallest area tributary (contributing load) to a support or to a simple-span of rail. That area is the Effective Wind Area, the total area of the fewest number of modules on a run of rails. If the smallest area of continuous modules exceeds 100 sq ft, use 100 sq ft (See Table 2). If less, round down to values available in Table 2. 0 P.Ke 3