Tables 1 and 2: Base Mount Capacity in Landscape and Portrait Orientations

Transcription

1 Quick Rack V1.1 Base Mount Code Compliance Review June 6, 2014 Page 1 of 4 June 6, 2014 Quick Mount PV 2700 Mitchell Drive, Building 2 Walnut Creek, CA Attn: Re: Stuart Wentworth, Chief Technical Officer Quick Mount PV Quick Rack V1.1 Base Mount Code Compliance Review TM Job No. 2013, Dear Stuart, We have reviewed the Quick Rack V1.1 photovoltaic (PV) array mounting system (base mount) and determined that, for the configurations and criteria described below, it complies with the structural requirements of the 2012 International Building Code, the 2013 California Building Code, and both ASCE 7-05 and ASCE The Quick Rack base mount consists of a base extrusion ( QBlock Slider ) that fastens to a supporting roof rafter, and an adjustable height top extrusion ( Top Slider ) that connects to the QBlock Slider with a stainless steel machine bolt. The PV modules are connected to the Top Slider by a 5/16 stainless steel (grade 18/8) machine bolt that fits into a track in the Top Slider ( track ) and together with a two-part clamp (consisting of a clamp base and a lipped panel clamp ) clamps the modules to the Top Slider. The QBlock Slider is anchored to the roof with a 5/16 nominal diameter structural screw, defined as either a 5/16 nominal diameter GRK RSS screw with Climatek coating or a 5/16 nominal diameter QMPV Dual-Drive screw. The typical horizontal (cross-slope) spacing of Quick Rack base mounts is four feet on center, with tighter spacing sometimes required in regions with extreme wind and snow loads. Larger spacing can be achieved in regions of low wind and snow loads. The attached sketches 1 through 4 illustrate the assembly and nomenclature of the various parts of the Quick Rack base mount system. Sketches 5 and 6 illustrate wind and snow considerations, and sketches 7 to 10 illustrate conventional base mount layouts (straight columns and rows) and staggered base mount layouts. The attached tables define the range of roof slopes, wind speeds, wind exposure categories, roof wind zones, ground snow loads and seismic zones where particular configurations of Quick Rack installations are allowed. Base Mount Capacity: Tables 1 and 2 define permissible configurations based on the anchorage capacity of the base mounts themselves, for modules installed in landscape and portrait orientation, respectively. Roof Capacity: Table 3 examines the structural capacity of typical code-compliant roof framing, and shows where a conventional layout of base mounts can be used, and where a staggered pattern is recommended instead. Tables 1 and 2: Base Mount Capacity in Landscape and Portrait Orientations The allowable capacity of Quick Rack base mount installations are based on allowable upward, downward, lateral, and combined downward-lateral load values determined from tests on actual Quick Rack base mount specimens conducted at Applied Materials & Engineering in Oakland, CA on June 25-27, 2013, following ICC AC-13 and ICC AC-428 provisions.

2 Quick Rack V1.1 Base Mount Code Compliance Review June 6, 2014 Page 2 of 4 Table 3: Existing Roof Rafter Capacity Typical base mount layouts concentrate loads on every second, third or fourth rafter. Assuming the existing roof can support code-required loads, Table 3 indicates where such concentrated loading is likely to be structurally acceptable, and where staggered layouts to create a more uniform distribution of loads is recommended instead. Table 3 is based on methods described in the structural technical appendix of the East Bay Green Corridor s Streamlined Structural Permitting for Residential Photovoltaic Installations. General Requirements The attached tables are subject to the requirements shown in the attached sketches and table footnotes, and the criteria listed below: Region and Site: 1. The roof is not in a special topographic region subject to wind speed-up effects, such as near or at the crest of a tall ridge or hill (i.e. ASCE 7 topographic factor of 1.00). Refer to ASCE 7-05 Sec or ASCE 7-10 Sec for determining if a roof is in a special wind speed-up zone. 2. The building is not a special occupancy structure such as a public school, public safety building or assembly building (i.e. ASCE 7-05 importance factor for wind, snow and seismic loads of 1.00, or Risk Category II building for ASCE 7-10). 3. In general, Quick Rack base mount capacity exceeds seismic lateral demands in almost all areas of the United States. The tables list minor limitations in unusual regions where combined high snow and seismic loads may occur. Roof Characteristics: 1. The installation is on wood-framed roofs with composition shingle, wood sawn shingle, built-up roofing, or membrane roofs, underlain by plywood, oriented strand board or solid 1x sheathing. 2. The existing roof structure should be generally code-compliant, and should not show signs of decay, fire damage, significant added dead loads, structural modifications (such as removal of web members from carpenter trusses) or any other condition that may weaken its load-carrying capacity. If there is doubt about the suitability of the roof to carry the new PV array, a qualified licensed engineer should be retained to inspect and analyze the existing roof structure. 3. The PV array is installed on the roof of an enclosed building with a mean roof height less than or equal to 35 feet (see sketch 6). The mean roof height is defined as the average height of the roof eave and the highest point on the roof. 4. The roof pitch is between 2:12 (9.5 degrees) and 12:12 (45 degrees). 5. Rafters have a minimum nominal width of 2 (1.5 actual width), and have a specific gravity of 0.42 or greater, allowing lumber species groups that range from relatively lightweight, such as Spruce-Pine-Fir, Hem-Fir and Close Grain Redwood, to denser woods such as Douglas Fir and Southern Pine.

3 Quick Rack V1.1 Base Mount Code Compliance Review June 6, 2014 Page 3 of 4 6. In existing construction, rafters are dry and seasoned. In new construction, rafters are either Kild-Dried (KD) or Surfaced Dry (S-DRY), or if Surfaced Green (S-GRN), have an in-field measured moisture content of 19% or less. Installation Specifics: 1. The maximum short edge panel width for PV modules installed in landscape orientation is The maximum long edge panel length for PV modules installed in portrait orientation is Each Quick Rack base mount is fastened to the roof rafter with one 5/16 nominal diameter structural screw, defined as either a 5/16 nominal diameter GRK RSS screw with Climatek coating or a 5/16 nominal diameter QMPV Dual-Drive screw, each pre-drilled with an 1/8 pilot hole to prevent splitting. The structural screw shall be embedded at least 2.5 into the roof rafter. The structural screw shall be torqued to achieve a snug fit of the mount to the flashing (the QBlock Slider should not be able to rotate easily). 4. For all PV module orientations, the Quick Rack base mount Top Slider tracks are positioned parallel to roof slope and connect to the module edges that run perpendicular to the slope. The base mount elevated seal region may point in either cross-slope direction (nominal east or west). 5. The PV modules shall be clamped to the Quick Rack track using the provided two-part clamp (clamp base and panel clamp) and a 5/16 stainless steel (grade 18/8) machine bolt, torqued to a minimum of 13 ft-lb. The center of the machine bolt into the track shall be installed no more than 1.5 upslope or downslope from the center of the track. Machine bolts may be installed in any position along the slots in the clamp. 6. The maximum PV module cantilever from the edge-most Quick Rack base mount is noted in each table for its respective PV module orientation and mount spacing. 7. Per the intent of AC-428, the edge of the PV array shall be no closer to any edge, eave, rake, hip, or ridge of the roof than two times the gap between the roof and underside of the PV modules. 8. To prevent excessive snow build-up, where the ground snow load exceeds 10 psf, the top edge of the PV array shall be set no farther than 5 feet from the roof ridge, measured perpendicular to the ridge. Note that local fire jurisdictions sometimes require that the top edge of the array be set no closer than a certain distance (often 3 feet) to the ridge. 9. If a skirt is installed along the bottom and/or top edge of an array, it shall have a minimum gap of 1/2 to the roof surface. Nominal left and right edges of the array shall remain open. 10. The dead load of the PV array (sum of the PV modules and Quick Rack base mount hardware) does not exceed 3.5 psf. 11. This code compliance report is limited to base mount structural performance. The modules installed in combination with Quick Rack shall also have UL 1703/2703 rated load capacities appropriate for the site s wind and snow loads.

4 Quick Rack V1.1 Base Mount Code Compliance Review June 6, 2014 Page 4 of 4 Conditions outside the assumptions and limitations listed above and in the attached sketches and tables may be feasible, but shall be investigated in consultation with Quick Mount PV, and, where appropriate, reviewed by a licensed professional engineer. Please call if you have any questions. Sincerely, David Mar, SE Principal Encl. Sketches 1 to 10 Tables 1 to 3 Appendices 1 to 2 Glossary of Symbols Code Compliance Letter CA.odt

5 Quick Rack V1.1 Base Mount Code Compliance Review June 6, 2014 Page 1 of 4 June 6, 2014 Quick Mount PV 2700 Mitchell Drive, Building 2 Walnut Creek, CA Attn: Re: Stuart Wentworth, Chief Technical Officer Quick Mount PV Quick Rack V1.1 Base Mount Code Compliance Review TM Job No. 2013, Dear Stuart, We have reviewed the Quick Rack V1.1 photovoltaic (PV) array mounting system (base mount) and determined that, for the configurations and criteria described below, it complies with the structural requirements of the 2012 International Building Code, and both ASCE 7-05 and ASCE The Quick Rack base mount consists of a base extrusion ( QBlock Slider ) that fastens to a supporting roof rafter, and an adjustable height top extrusion ( Top Slider ) that connects to the QBlock Slider with a stainless steel machine bolt. The PV modules are connected to the Top Slider by a 5/16 stainless steel (grade 18/8) machine bolt that fits into a track in the Top Slider ( track ) and together with a two-part clamp (consisting of a clamp base and a lipped panel clamp ) clamps the modules to the Top Slider. The QBlock Slider is anchored to the roof with a 5/16 nominal diameter structural screw, defined as either a 5/16 nominal diameter GRK RSS screw with Climatek coating or a 5/16 nominal diameter QMPV Dual-Drive screw. The typical horizontal (cross-slope) spacing of Quick Rack base mounts is four feet on center, with tighter spacing sometimes required in regions with extreme wind and snow loads. Larger spacing can be achieved in regions of low wind and snow loads. The attached sketches 1 through 4 illustrate the assembly and nomenclature of the various parts of the Quick Rack base mount system. Sketches 5 and 6 illustrate wind and snow considerations, and sketches 7 to 10 illustrate conventional base mount layouts (straight columns and rows) and staggered base mount layouts. The attached tables define the range of roof slopes, wind speeds, wind exposure categories, roof wind zones, ground snow loads and seismic zones where particular configurations of Quick Rack installations are allowed. Base Mount Capacity: Tables 1 and 2 define permissible configurations based on the anchorage capacity of the base mounts themselves, for modules installed in landscape and portrait orientation, respectively. Roof Capacity: Table 3 examines the structural capacity of typical code-compliant roof framing, and shows where a conventional layout of base mounts can be used, and where a staggered pattern is recommended instead. Tables 1 and 2: Base Mount Capacity in Landscape and Portrait Orientations The allowable capacity of Quick Rack base mount installations are based on allowable upward, downward, lateral, and combined downward-lateral load values determined from tests on actual Quick Rack base mount specimens conducted at Applied Materials & Engineering in Oakland, CA on June 25-27, 2013, following ICC AC-13 and ICC AC-428 provisions.

6 Quick Rack V1.1 Base Mount Code Compliance Review June 6, 2014 Page 2 of 4 Table 3: Existing Roof Rafter Capacity Typical base mount layouts concentrate loads on every second, third or fourth rafter. Assuming the existing roof can support code-required loads, Table 3 indicates where such concentrated loading is likely to be structurally acceptable, and where staggered layouts to create a more uniform distribution of loads is recommended instead. Table 3 is based on methods described in the structural technical appendix of the East Bay Green Corridor s Streamlined Structural Permitting for Residential Photovoltaic Installations. General Requirements The attached tables are subject to the requirements shown in the attached sketches and table footnotes, and the criteria listed below: Region and Site: 1. The roof is not in a special topographic region subject to wind speed-up effects, such as near or at the crest of a tall ridge or hill (i.e. ASCE 7 topographic factor of 1.00). Refer to ASCE 7-05 Sec or ASCE 7-10 Sec for determining if a roof is in a special wind speed-up zone. 2. The building is not a special occupancy structure such as a public school, public safety building or assembly building (i.e. ASCE 7-05 importance factor for wind, snow and seismic loads of 1.00, or Risk Category II building for ASCE 7-10). 3. In general, Quick Rack base mount capacity exceeds seismic lateral demands in almost all areas of the United States. The tables list minor limitations in unusual regions where combined high snow and seismic loads may occur. Roof Characteristics: 1. The installation is on wood-framed roofs with composition shingle, wood sawn shingle, built-up roofing, or membrane roofs, underlain by plywood, oriented strand board or solid 1x sheathing. 2. The existing roof structure should be generally code-compliant, and should not show signs of decay, fire damage, significant added dead loads, structural modifications (such as removal of web members from carpenter trusses) or any other condition that may weaken its load-carrying capacity. If there is doubt about the suitability of the roof to carry the new PV array, a qualified licensed engineer should be retained to inspect and analyze the existing roof structure. 3. The PV array is installed on the roof of an enclosed building with a mean roof height less than or equal to 35 feet (see sketch 6). The mean roof height is defined as the average height of the roof eave and the highest point on the roof. 4. The roof pitch is between 2:12 (9.5 degrees) and 12:12 (45 degrees). 5. Rafters have a minimum nominal width of 2 (1.5 actual width), and have a specific gravity of 0.42 or greater, allowing lumber species groups that range from relatively lightweight, such as Spruce-Pine-Fir, Hem-Fir and Close Grain Redwood, to denser woods such as Douglas Fir and Southern Pine.

7 Quick Rack V1.1 Base Mount Code Compliance Review June 6, 2014 Page 3 of 4 6. In existing construction, rafters are dry and seasoned. In new construction, rafters are either Kild-Dried (KD) or Surfaced Dry (S-DRY), or if Surfaced Green (S-GRN), have an in-field measured moisture content of 19% or less. Installation Specifics: 1. The maximum short edge panel width for PV modules installed in landscape orientation is The maximum long edge panel length for PV modules installed in portrait orientation is Each Quick Rack base mount is fastened to the roof rafter with one 5/16 nominal diameter structural screw, defined as either a 5/16 nominal diameter GRK RSS screw with Climatek coating or a 5/16 nominal diameter QMPV Dual-Drive screw, each pre-drilled with an 1/8 pilot hole to prevent splitting. The structural screw shall be embedded at least 2.5 into the roof rafter. The structural screw shall be torqued to achieve a snug fit of the mount to the flashing (the QBlock Slider should not be able to rotate easily). 4. For all PV module orientations, the Quick Rack base mount Top Slider tracks are positioned parallel to roof slope and connect to the module edges that run perpendicular to the slope. The base mount elevated seal region may point in either cross-slope direction (nominal east or west). 5. The PV modules shall be clamped to the Quick Rack track using the provided two-part clamp (clamp base and panel clamp) and a 5/16 stainless steel (grade 18/8) machine bolt, torqued to a minimum of 13 ft-lb. The center of the machine bolt into the track shall be installed no more than 1.5 upslope or downslope from the center of the track. Machine bolts may be installed in any position along the slots in the clamp. 6. The maximum PV module cantilever from the edge-most Quick Rack base mount is noted in each table for its respective PV module orientation and mount spacing. 7. Per the intent of AC-428, the edge of the PV array shall be no closer to any edge, eave, rake, hip, or ridge of the roof than two times the gap between the roof and underside of the PV modules. 8. To prevent excessive snow build-up, where the ground snow load exceeds 10 psf, the top edge of the PV array shall be set no farther than 5 feet from the roof ridge, measured perpendicular to the ridge. Note that local fire jurisdictions sometimes require that the top edge of the array be set no closer than a certain distance (often 3 feet) to the ridge. 9. If a skirt is installed along the bottom and/or top edge of an array, it shall have a minimum gap of 1/2 to the roof surface. Nominal left and right edges of the array shall remain open. 10. The dead load of the PV array (sum of the PV modules and Quick Rack base mount hardware) does not exceed 3.5 psf. 11. This code compliance report is limited to base mount structural performance. The modules installed in combination with Quick Rack shall also have UL 1703/2703 rated load capacities appropriate for the site s wind and snow loads.

8 Quick Rack V1.1 Base Mount Code Compliance Review June 6, 2014 Page 4 of 4 Conditions outside the assumptions and limitations listed above and in the attached sketches and tables may be feasible, but shall be investigated in consultation with Quick Mount PV, and, where appropriate, reviewed by a licensed professional engineer. Please call if you have any questions. Sincerely, Steven B. Tipping, PE President Encl. Sketches 1 to 10 Tables 1 to 3 Appendices 1 to 2 Glossary of Symbols Code Compliance Letter NY.odt

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19 Quick Rack V1.1 Base Mount Code Compliance Review Table 1. Quick Rack Base Mount Maximum Spacings, Modules in Landscape Orientation ASCE 7-05 (Service Level) 85 mph 90 mph 100 mph 110 mph 120 mph Wind Speed ASCE 7-10 (Strength Level) 110 mph 115 mph 125 mph 140 mph 150 mph Roof Pitch 2:12 to 6:12 7:12 to 12:12 2:12 to 6:12 7:12 to 12:12 2:12 to 6:12 7:12 to 12:12 2:12 to 6:12 7:12 to 12:12 2:12 to 6:12 7:12 to 12:12 Ground Snow Load 0-10 psf psf psf psf psf psf Wind Exposure Category B C D B C D B C D B C D B C D B C D 72" 72" 72" 72" 72" 72" 64" 64" 64" 48" 48" 48" 32" 32" 32" 32" 32" 32" 72" 72" 72" 72" 72" 72" 48" 48" 48" 32" 32" 32" 32" 32" 32" 24" 24" 32" 72" 72" 72" 72" 72" 72" 64" 64" 64" 48" 48" 48" 32" 32" 32" 32" 32" 32" 72" 72" 72" 72" 72" 72" 48" 48" 48" 32" 32" 32" 32" 32" 32" 24" 24" 32" 72" 72" 72" */64" 72" 72" 72" */64" 64" 64" 64" 48" 48" 48" 32" 32" 32" 32" 32" 32" 72" 72" 72" 72" 72" 72" 48" 48" 48" 32" 32" 32" 32" 32" 32" 24" 24" 32" 72" 72" */64" 72" */48" 72" 72" */64" 72" */48" 64" 64" 64" */48" 48" 48" 48" 32" 32" 32" 32" 32" 32" 72" 72" 64" 72" 72" 64" 48" 48" 48" 32" 32" 32" 32" 32" 32" 24" 24" 32" 72" 72" */48" 64" */32" 72" 72" */48" 64" */32" 64" 64" */48" 64" */32" 48" 48" 48" */32" 32" 32" 32" 32" 32" 32" 72" 64" 48" 72" 64" 48" 48" 48" 48" 32" 32" 32" 32" 32" 32" 24" 24" 32" Table Notes: 1. The Quick Rack base mount maximum allowable spacings listed in this table are the maximum allowable spacings between base mounts in the roof cross-slope direction for module in landscape orientation. 2. The maximum short edge PV module width is 40". 3. Where two numbers are shown, such as 72"*/64", the first number is the maximum allowable spacing when the PV array is within roof zone 1, and the second number is the maximum allowable spacing otherwise. 4. The PV module cantilever is defined as the distance from the nominal east or west array edge to the center of the structural screw. The maximum cantiliever is 18" for spacings greater than or equal to 48", and 9" for spacings less than 48". When the nominal east or west array edge is entirely within roof zone 1 and the spacing in the table does not have an asterisk (*), the maximum cantilever is permitted to be extended to one-half the mount spacing or 24", whichever is smaller. 5. Seismic: The maximum spacings in this table are subject to the following limitations on S DS : 72" : high seismic zones (S DS 1.5g) 64" : high seismic zones (S DS 1.5g for ground snow load greater than 20 psf, otherwise S DS 1.75g ) 48" and smaller : high seismic zones (S DS 2.0g) 6. This table is subject to the conditions stated in the attached Code Compliance Letter, and shown in the attached sketches. 7. This table is based on ASCE 7-05 and ASCE ASCE 7-10 wind speeds are back-calculated from ASCE 7-05 wind speeds to produce the same wind pressures on a Risk Cateogy II building. 8. See Table 3 for regions of high wind or snow load where a staggered base mount layout is recommended.

20 Quick Rack V1.1 Base Mount Code Compliance Review Table 2. Quick Rack Base Mount Maximum Spacings, Modules in Portrait Orientation ASCE 7-05 (Service Level) 85 mph 90 mph 100 mph 110 mph 120 mph Wind Speed ASCE 7-10 (Strength Level) 110 mph 115 mph 125 mph 140 mph 150 mph Ground Snow Load 0-15 psf psf Wind Exposure Category psf Roof Pitch B C D B C D B C D 2:12 to 6:12 48" 48" 48" 32" 32" 32" 24" 24" 24" 7:12 to 12:12 48" 48" 48" 32" 32" 32" 24" 24" 24" 2:12 to 6:12 48" 48" 48" 32" 32" 32" 24" 24" 24" 7:12 to 12:12 48" 48" 48" 32" 32" 32" 24" 24" 24" 2:12 to 6:12 48" 48" 48" */32" 32" 32" 32" 24" 24" 24" 7:12 to 12:12 48" 48" 48" 32" 32" 32" 24" 24" 24" 2:12 to 6:12 48" 48" */32" 48" */32" 32" 32" 32" 24" 24" 24" 7:12 to 12:12 48" 48" 32" 32" 32" 32" 24" 24" 24" 2:12 to 6:12 48" 48" */32" 32" */24" 32" 32" 32" */24" 24" 24" 24" 7:12 to 12:12 48" 32" 32" 32" 32" 32" 24" 24" 24" Table Notes: 1. The Quick Rack base mount maximum allowable spacings listed in this table are the maximum allowable spacings between base mounts in the roof cross-slope direction for modules in portrait orientation. 2. The maximum long edge PV module length is 65.5". 3. Where two numbers are shown, such as 48"*/32", the first number is the maximum allowable spacing when the PV array is within roof zone 1, and the second number is the maximum allowable spacing otherwise. 4. The PV module cantilever is defined as the distance from the nominal east or west array edge to the center of the structural screw. The maximum module cantilever is 9" for all mount spacings. 5. Seismic: Acceptable in high seismic zones (S DS 1.5g) for ground snow loads less than or equal to 10 psf, and moderate seismic zones (S SD 1.0g) for ground snow loads greater than 10 psf. 6. This table is subject to the conditions stated in the attached Code Compliance Letter, and shown in the attached sketches. 7. This table is based on ASCE 7-05 and ASCE ASCE 7-10 wind speeds are back-calculated from ASCE 7-05 wind speeds to produce the same wind pressures on a Risk Cateogy II building. 8. See Table 3 for regions of high wind or snow load where a staggered mount layout is recommended.

21 Quick Rack V1.1 Base Mount Code Compliance Review Table 3. Existing Roof Rafter Capacity Assessment Ground Snow Load 0 psf 1-10 psf > 10 psf Table Notes: Wind Exposure Category Wind Speed B C D ASCE 7-05 ASCE 7-10 n = # of Rafter Spaces Between Quick Rack Base Mounts (Service Level) (Strength Level) Roof Pitch n = 1 n = 2 n = 3 n = 4 n = 1 n = 2 n = 3 n = 4 n = 1 n = 2 n = 3 n = 4 85 mph 110 mph 2:12 to 6:12 OK OK OK OK OK OK OK OK OK OK OK SA 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 90 mph 115 mph 2:12 to 6:12 OK OK OK OK OK OK OK SA OK OK OK SA 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 100 mph 125 mph 2:12 to 6:12 OK OK OK OK OK OK OK SA OK OK SA SA 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 110 mph 140 mph 2:12 to 6:12 OK OK OK SA OK OK SA SA OK OK SA SA 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 120 mph 150 mph 2:12 to 6:12 OK OK OK SA OK OK SA SA OK SA SA* SA** 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 85 mph 110 mph 2:12 to 6:12 OK OK SA SA OK OK SA SA OK OK SA SA 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 90 mph 115 mph 2:12 to 6:12 OK OK SA SA OK OK SA SA OK OK SA SA 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 100 mph 125 mph 2:12 to 6:12 OK OK SA SA OK OK SA SA OK OK SA SA 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 110 mph 140 mph 2:12 to 6:12 OK OK SA SA OK OK SA SA OK OK SA SA 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 120 mph 150 mph 2:12 to 6:12 OK OK SA SA OK OK SA SA OK SA SA* SA** 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 85 mph 110 mph 2:12 to 6:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 90 mph 115 mph 2:12 to 6:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 100 mph 125 mph 2:12 to 6:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 110 mph 140 mph 2:12 to 6:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 120 mph 150 mph 2:12 to 6:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** 7:12 to 12:12 OK SA SA* SA** OK SA SA* SA** OK SA SA* SA** OK = If the existing roof is code compliant, it is likely to have sufficient strength to support a PV array without staggering base mounts. SA = Stagger Anchors, or Structurally Assess and Strengthen as Appropriate. See Sketches 7-10 for acceptable staggered base mount layouts. * The staggered pattern shown in Sketch 8 is NOT acceptable. Instead, reduce the base mount spacing and use the staggered pattern shown in Sketch 9. ** The staggered pattern shown in Sketch 7 is NOT acceptable. Instead, reduce the base mount spacing and use the staggered pattern shown in Sketch This table provides general guidelines for when a base mount layout that is anchored to every second, third or fourth rafter is likely to be acceptable, and when a staggered base mount layout or structural engineering assessment is recommended instead. 2. The installer and/or building owner is responsible for verifying that the existing roof can support code-required roof loads. 3. Concentrated loads on a rafter from Quick Rack base mounts are assumed to be partially shared with adjacent rafters as described in the Technical Appendix of the East Bay Green Corridor's Streamlined Structural Permitting for Residential Photovoltaic Installations. 4. Table based on ASCE 7-05 and ASCE ASCE 7-10 wind speeds are back-calculated from ASCE 7-05 wind speeds to produce the same wind pressures on a Risk Cateogy II building.

22 Appendix 1: June 6, 2014 Quick Rack Base Mount Allowable Load Values Page 1 of 11 Appendix 1: Quick Rack Base Mount Allowable Load Values The purpose of this Appendix is to document the allowable load values used to generate Tables 1 and 2 enclosed in the Quick Mount PV Quick Rack V1.1 Base Mount Code Compliance Review letter (Code Compliance Letter) dated June 6, The allowable Quick Rack base mount installations are based on allowable upward, downward, lateral, and combined downward-lateral load values determined from tests on actual Quick Rack specimens conducted at Applied Materials & Engineering (AME) in Oakland, CA on June 25-27, 2013, following ICC-AC13 and ICC-AC428 provisions. The allowable loads are determined from ultimate load values reduced by factors of safety that vary according to failure mode and design load duration. Test Description Tests were performed on Quick Rack base mounts installed in 2x4 Douglas-Fir rafters of nominal length with one 5/16 nominal diameter GRK RSS screw with Climatek coating pre-drilled with an 1/8 pilot hole and installed with 2.5 embedment into the rafter. The mount top extrusion was attached to the base in the highest possible configuration to capture the worst effects. The mounts were installed with the aluminum flashing and over two layers of composition shingle roofing over 1/2 nominal thickness plywood to simulate a typical installed condition. Tests were conducted to investigate the effect of the following three primary parameters on the behavior of the base mount under ultimate loads: (1) load direction, (2) position of the application of load on the top slider, and (3) roof slope (pitch). See Figure A1.1. Figure A1.1. Load directions and top slider loading positions.

23 Appendix 1: June 6, 2014 Quick Rack Base Mount Allowable Load Values Page 2 of Load Direction Load tests were conducted in each primary load direction to investigate the behavior of the base mount under pure loading. The four pure load directions are: (1) Upward load from the top slider track, (2) Downward load on the top slider track, (3) Down-slope lateral load in the direction of the slope of the roof, and (4) Cross-slope lateral load the direction of the elevated seal region. 2. Top Slider Loading Position The application of load on the top slider and its effect on the behavior of the base mount was investigated for certain load direction tests where the behavior was expected to be significantly different depending on the location from which the top slider was loaded. The top slider positions that were investigated are: 3. Roof Slope Position A: Centered on the top slider. Position B: Down-slope-most position on the top slider, defined as 1.5 down-slope from base mount centerline. Position C: Up-slope-most position on the top slider, defined as 1.5 up-slope from the base mount centerline. A series of downward load tests (load direction 2) were conducted on base mounts that were set on test beds sloped with a 6:12 pitch (~27 degree roof angle) to investigate the effect of combined downward and lateral parallel to roof loading on the base mount. This is a common case that occurs under snow loading. Table A1.1 summarizes the tests that were performed at AME (note that the G represents that the base mount was anchored to the rafter with a GRK RSS screw as described above). In all tests, the top slider was allowed to rotate freely. However, in actual installations, the top slider is firmly clamped to the PV modules. The flexural stiffness of the modules will tend to reduce moments imposed on the base mount. This means the allowable values from these tests are likely to be conservative, especially for the lateral and combined downward and lateral load cases.

24 Appendix 1: June 6, 2014 Quick Rack Base Mount Allowable Load Values Page 3 of 11 Table A1.1. Testing plan summary. Primary Test Parameters Load Direction Top Slider Loading Position Roof Slope Test Series Name A B C Flat 6:12 1-A-0-G X X X 1-C-0-G X X X 2-A-6-G X X X 2-B-0-G X X X 2-B-6-G X X X 3-C-0-G X X X 4-A-0-G X X X 4-C-0-G X X X Load Testing Summary Upward Load Tests (Load Direction 1) Two series of upward load tests were conducted, where in the first series the top rail was loaded from position A, and the second series from position C. From testing, it was determined that top rail position C produced smaller ultimate values, and was therefore taken as the controlling configuration for the allowable upward load. The ultimate behavior of the Quick Rack base mount subject to upward loading from top slider position C was characterized by rotation of the base mount toward the elevated seal region with associated uplift of the slider region, slight rotation of the base mount in the down-slope direction, bending of the base mount, bending and denting of the base flashing, moderate bending of the GRK screw (due to the rotation of the base mount) and screw pull-out. Bending of the base mount was concentrated at the interface between the bottom and slider section of the QBlock slider. Furthermore, the elevated seal region creates a quasi-fixed condition on the screw end and causes it to bend and follow the base mount as it rotates. This rotation is enabled by denting of the flashing, compression of the composition shingle roofing, and pull-out of the screw. Puncturing of the flashing was observed under the down-slope-most edge of the elevated seal region. However, observations at the allowable load indicate that these failures are not of concern, and are not considered for any serviceability limit state. Downward Load Tests (Load Direction 2) One downward load test series was conducted in top slider position B. Position A was not tested and was assumed not to control since loading from position B would have a tendency to rotate the base mount more than loading from position A. The dominant ultimate behavior of the base mount subject to pure downward loading was bending and cracking of the plywood directly beneath the base mount slider region. Other behavior

25 Appendix 1: June 6, 2014 Quick Rack Base Mount Allowable Load Values Page 4 of 11 included moderate rotation of the base mount toward the slider region accompanied by screw rotation, slight bending of the base mount at the slider region of the QBlock slider, and denting and crippling of the base flashing under the base mount slider region. After a series of three tests had been conducted to ultimate failure, a fourth test was conducted up to the approximate allowable load. The base mount was then un-installed to check for puncturing of the base flashing and crushing of the plywood. At the allowable load, there was no puncturing of the base flashing, nor was there evidence of damage to the plywood or composition shingle roofing. Thus, the allowable downward load is not controlled by a serviceability limit state. Down-slope Lateral Load Tests (Load Direction 3) One down-slope lateral load test series was conducted in the C top slider position. Due to the direction of loading, top slider position was not viewed as an influential variable, and top slider position C was chosen due to ease of testing. The ultimate behavior of the base mount in this load direction was typically characterized by moderate rotation of the base mount in the down-slope direction and uplift of the up-slope edge, moderate screw rotation and pull-out, moderate bending of the base flashing, and denting and puncturing of the base flashing under the down-slope edge. In some instances, tests from this series ended prematurely due to end of travel limitations, where the machine test head exceeded the expected travel distance (due to larger than expected rotations of the base mount) and disengaged from the intended loading surface. In these cases, the ultimate load was taken as the applied load when this occurred. Observations at the allowable load showed no sign of excessive base mount rotation, screw bending or pullout, or base flashing puncture, so those serviceability limit states do not control. Cross-Slope Lateral Toward Elevated Seal Region Load Tests (Load Dir. 4) Base mount tests in this load direction were conducted in the A and C top slider positions. Due to the relatively short moment resisting arm between the GRK screw and the edge of the base mount as compared to the overturning arm, the base mount exhibits relatively low strength and stiffness in this load direction, and there was no appreciable difference in ultimate load between the two top slider positions. The behavior at ultimate load is characterized by moderate rotation of the base mount toward the elevated seal region and uplift of the slider region, moderate screw bending and pull-out, bending of the QBlock slider, and slight bending and denting of the base flashing. Observations at the allowable load level indicate significant rotation of the base mount. However, since the primary action that causes loading in this direction is due to seismic events, such rotations were deemed acceptable. Other serviceability limit states were not considered. Combined Downward and Down-Slope Lateral Tests Two test series used 6:12 sloped test beds to study the interaction of downward and down-slope lateral loads on the base mount, first in the A position and then in the B position. Because of the tendency of the mount to rotate due to downward load when loaded in the B position, the base mounts were typically weaker and more flexible in the B position than in the A position. Therefore, the controlling ultimate values were determined from the B series tests.

26 Appendix 1: June 6, 2014 Quick Rack Base Mount Allowable Load Values Page 5 of 11 The behavior at ultimate load was characterized by rotation of the base mount in the down-slope direction and uplift of the up-slope edge, slight screw bending and pull-out, bending of the base flashing, and denting of the base flashing under the down-slope edge. For some tests, the ultimate load was taken as the load at the point when the test head slipped off the intended loading surface and no longer loaded the base mount in the correct location. The load-displacement curves from this test series were characterized by several cycles of load increase to a certain level followed by an immediate drop in load, caused by stick-slipping of the test head against the loading surface. Several measures were taken to prevent further stick-slipping in subsequent tests, including changing test heads, but this phenomenon was not eliminated completely. Serviceability limit states were not considered. Allowable Load Adjustments Per ICC-AC 13, for failure modes associated with failure of wood or attachments into wood (such as GRK RSS screw withdrawal and bending), the ultimate load is determined as the minimum of three test load values where each test load does not deviate from the average by more than +/- 20%, or the average of six test load values. The allowable decade-long duration load (i.e. with a wood load duration factor of 1.00) is the ultimate load divided by a Factor of Safety (FOS) of three. The allowable load for other duration loads, such as dead load (permanent), snow (duration of two months or less), and wind or seismic (duration of 10 minutes or less), are adjusted from the decade-long allowable load by multiplying by their load duration factors of 0.90, 1.15, and 1.60, respectively (the load duration factors are listed in Appendix B of the 2005 National Design Specification for Wood Construction (NDS-2005)). Alternatively, the FOS for these load durations is divided by its respective load duration factor. Table A1.2 summarizes the load duration factors and factors of safety for each load duration type. Table A1.2. Load duration factors and factors of safety for the pertinent load types. Load Type Load Duration Factor Factor of Safety (FOS) Dead (permanent) / 0.90 = 3.33 Snow (two months or less) / 1.15 = 2.61 Wind or Seismic (10 minutes or less) / 1.60 = 1.88 As described above, tests of Quick Rack base mounts were conducted in rafters of species Douglas-Fir, which has a nominal specific gravity G = Douglas-Fir was chosen as the testing wood because of its availability on the West Coast of the United States. In order to extend the applicability of Quick Rack base mount installations to other parts of the United States, where the typical wood stock is less dense than Douglas-Fir (i.e. the specific gravity is lower than 0.49), the allowable load values need to be adjusted to correspond to wood with a lower specific gravity. Spruce-Pine-Fir, with a nominal specific gravity of G = 0.42, was chosen as the target wood species. For each test series, the average specific gravity of the wood specimens from the applicable tests was determined. The ultimate load was then adjusted for specific gravity by the following relation:

27 Appendix 1: June 6, 2014 Quick Rack Base Mount Allowable Load Values Page 6 of 11 where P ult, adj =( G test) P ult, test P ult,test G test P ult,test P ult,adj = average specific gravity from the applicable tests = ultimate load determined from testing = specific gravity adjusted ultimate load The Quick Rack base mount allowable load value is then calculated by the following relation: where P allow = P ult,adj FOS CD FOS C_D = applicable factor of safety for the load duration from Table A1.2 P allow = allowable load value for a specific load duration The Quick Rack base mount allowable load values for each load direction are summarized in Table A1.3. These loads are the basis for the Quick Rack allowable installation tables in the Code Compliance Letter. Table A1.3. Quick Rack allowable load values. Load Direction Upward Governing Test Series 1-C-0-G Failure Mode GRK screw bending and pull-out, base mount bending Specific Gravity Adjusted Ultimate Load Dead Allowable Load Snow Wind or Seismic Avg. of lb. 356 lb. 455 lb. 633 lb. Downward 2-B-0-G Plywood bending Min. of lb. 950 lb lb lb. Down-Slope Lateral Cross-Slope Lateral toward Elevated Seal Region Combined Downward and Down-Slope Lateral 3-C-0-G 4-A-0-G 2-B-6-G GRK screw bending and pull-out, excessive base mount Avg. of lb. 85 lb. 108 lb. 150 lb. rotation GRK screw bending and pull-out, base mount bending Min. of 3 50 lb. n/a n/a 80 lb. Excessive base mount rotation Avg. of lb. 286 lb. 366 lb. 509 lb. = In some tests, the test ended when the machine test head disengaged from the intended loading surface due to excessive rotation of the base mount. In these instances, the test load was taken as the load when this occurred. = Large rotation of base mount. Test ended when test head slipped off of loading surface.

28 Appendix 1: June 6, 2014 Quick Rack Base Mount Allowable Load Values Page 7 of 11 Determination of Base Mount Demand-to-Capacity Ratio The allowable Quick Rack base mount installations summarized in Tables 1 and 2 are based on a demand-to-capacity ratio analysis, in which the load demand from the controlling (largest) load combination of dead, snow, wind, and/or seismic loads is divided by the controlling (lowest) capacity of the base mount, to produce a demand-to-capacity ratio (DCR). DCR s less than or equal to 1.0 indicate that the base mount has adequate strength to resist the applied loads, and that use of the base mount is acceptable. The load demands and determination of the Quick Rack base mount capacity is described next. Load Demands The following basic load types were considered: D = dead load S = snow load W(down) = ASD wind load toward the roof W(up) = ASD wind load away from the roof E =seismic Each basic load type acts in a unique direction, as defined by ASCE 7-05, and shown visually in Figure A1.2. Each load type is decomposed into its parallel and normal to the plane of the roof components. These basic loads are then combined using the applicable ASD load combinations from ASCE 7-05 Sec 2.4: 1) 1.0*D 2) 1.0*D + 1.0*S 3) 1.0*D + 1.0*W(down) 4) 1.0*D *W(down) *S 5) ( *SDS)*D *E *S 6) 0.6*D + 1.0*W(up) For each load combination, the magnitude of the load parallel (P ) and normal (P ) to the roof is determined, and the resultant load, P, and load angle, α, is calculated. P= P 2 +P 2 α=arctan( P P ) Quick Rack Base Mount Capacity The capacity of the Quick Rack base mount is defined by the weakest of the following five capacities: 1) Combined parallel and normal to the roof allowable load capacity of the Quick Rack base mount itself, based on test results, 2) Combined withdrawal and lateral load capacity of the GRK RSS screw based on allowable capacities published in ICC-ESR 2442,

29 Appendix 1: June 6, 2014 Quick Rack Base Mount Allowable Load Values Page 8 of 11 3) A minimum clamping force provided by the 5/16 stainless steel (grade 18/8) machine bolt of two times the wind uplift demand (per UL 2703), 4) A minimum slip resistance between the PV array and the top slider of two times the load demand parallel to the roof (per UL 2703), and 5) The axial capacity of the machine bolt. For the allowable installations presented in Table 1 and 2 in the Code Compliance Letter, capacity 1 or 2 always controlled. Capacity of the Quick Rack Base Mount Itself The capacity of the Quick Rack base mount itself under combined parallel and normal to the roof loads is determined through the use of a load interaction diagram based on the allowable loads in Table 3. Figure A1.3 shows the interaction diagram for snow load duration (C D = 1.15). The capacity of the Quick Rack base mount is a function of the load angle, α, of the load demands from the controlling load combination. The point of intersection of a line through the origin with angle α and the interaction diagram defines the capacity of the Quick Rack base mount for load parallel and normal to the roof. The Quick Rack load capacity, R QR, is the resultant of the parallel and normal load capacities. The DCR of the Quick Rack base mount is calculated: DCR QR = P R QR Figure A1.2. Basic load types (dead, snow and wind) and definitions for load parallel (P ) and normal (P ) to roof, load angle (α), and resultant load (P).

30 Appendix 1: June 6, 2014 Quick Rack Base Mount Allowable Load Values Page 9 of 11 Figure A1.3. Quick Rack base mount interaction diagram using allowable load values determined from testing. This interaction diagram is adjusted for a snow load duration (C D = 1.15). Similar interaction diagrams are defined for dead load (C D = 0.90) and wind/seismic (C D = 1.60). Capacity of the GRK RSS Screw Per ICC-ESR 2442, the capacity of the GRK RSS screw under combined withdrawal and lateral loads is determined by NDS-05 Sec The capacity of the GRK RSS screw, Z α, is also a function of the load angle. The DCR of the GRK RSS screw is: DCR GRK = P Z α '

31 Appendix 1: June 6, 2014 Quick Rack Base Mount Allowable Load Values Page 10 of 11 Minimum Clamping Force The clamping force provided by the machine bolt can be related to torque through the relation: W = T μ b D where: W = clamping force T = torque μ b = bolt coefficient of friction = 0.25 (per UL 2703) D = bolt diameter = inches For the load combination including upward wind loads (wind loads away from the roof), the DCR for clamping is calculated: where: P W = load demand normal to the roof DCR clamp = 2 P +W + T W + T = increase in clamping force due to the differential strains between the PV modules and the machine bolt because of an increase in temperature Slip Resistance Resistance to slip is provided by the friction force that acts between the panels, the clamp, and the top slider. The friction force is calculated as: where: R f =μ p ( P +W W T ) μ b = coefficient of friction between the panel and the top slider = 0.30 (per UL 2703) P = load demand normal to the roof W = clamping force W - T = decrease in clamping force due to the differential strains between the PV modules and the machine bolt because of a decrease in temperature The DCR for resistance to slip is calculated: DCR slip = 2 P R f where: P = load demand parallel to the roof

32 Appendix 1: June 6, 2014 Quick Rack Base Mount Allowable Load Values Page 11 of 11 Axial Capacity of the Machine Bolt From in-house testing performed at Quick Mount PV, the strength of the machine bolt was determined by incrementally increasing the torque on the machine bolt until failure. Failure consistently occurred around 40 ft-lb. Thus, a maximum torque of 20 ft-lb on the machine bolt is recommended. Controlling DCR The controlling DCR of the Quick Rack base mount for a given combination of basic loads is the largest DCR from the individual components above: DCR max =max( DCR QR,DCR GRK,DCR clamp,dcr slip ) Appendix 1 Allowable Load Values.odt

33 Appendix 2: June 6, 2014 Quick Rack Base Mount Code Compliance Review Technical Notes Page 1 of 3 Appendix 2: Quick Rack Base Mount Code Compliance Review Technical Notes The purpose of this Appendix is to expand on the loading assumptions used to generate the tables enclosed in the Quick Mount PV Quick Rack V1.1 Base Mount Code Compliance Review letter (Code Compliance Letter) dated June 6, Enclosed in that letter are three tables: Tables 1 and 2 present allowable Quick Rack base mount installations for PV modules oriented in landscape and portrait, respectively; and Table 3 shows when an existing code-compliant roof rafter is likely to be able to support the addition of a PV array with the base mount spacing indicated, and when staggering base mounts to create a more uniform distribution of load is recommended. In addition to the conditions described in the Code Compliance Letter, additional assumptions and limitations common to all three tables are described in Section A of this Appendix. Tables 1 and 2 are further subject to the assumptions and limitations described in Section B of this Appendix, and Table 3 to those described in Section C of this Appendix. Sections A, B, and C are presented next. Section A. Technical Notes Common to All Tables Load Criteria: Wind Loads: Calculation of code wind load demands is per ASCE 7-05 Chapter 6 for Components and Cladding (Sec ) modified for an internal pressure coefficient, GCpi = 0, per ICC-AC 428. The basic wind speed (V), wind directionality factor (K d ), velocity pressure exposure coefficient (K z ), topographic factor (K zt ), importance factor (I), and exposure categories (B, C & D) are as defined by ASCE External pressure coefficients for uplift zones 1 (interior), 2 (edge), and 3 (corner) and roof downward zone are as defined by ASCE 7-05 for a given roof geometry and slope (figures 6-11B thru 6-11D). ASCE 7-10 wind speeds are back-calculated from ASCE 7-05 wind speeds so that the pressures are nearly identical for a Risk Category II building. See Table C in the ASCE 7-10 commentary. Snow Loads: Calculation of code snow load demands is per ASCE 7-05 Chapter 7. The ground snow load (p g ), exposure factor (C e ), thermal factor (C t ), roof slope factor (C s ), importance factor (I), and terrain categories (B, C & D) are as defined by ASCE Applicable snow load provisions in ASCE 7-10 remain unchanged. Since the site will generally be open to the south for solar exposure, the roof snow exposure condition is assumed to be either partially exposed or fully exposed.