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GUIDELINES FOR PERMITTING A RESIDENTIAL <br />PHOTOVOLTAIC (PV) SYSTEM <br />3 <br />30!. 4!",%3: <br />A framing plan is required only if the combined weight of the PV array exceed 5 pounds per <br />2 <br />square foot (PSF or lbs/ ft) or, the existing rafters are over-spanned. The following may help <br />determine if the rafters are over-spanned. <br />Use this table for rafter spans that have conventional lightweight dead loads. If there is a roof <br /> consider obtaining the advice of a State of Hawaii <br />registered professional Architect or Structural Engineer. <br />10 PSF Dead Load <br />Roof live load= 20 psf, ceiling not attached to rafters <br />Rafter Size 2 x 4 2 x 6 2 x 8 2 x 10 2 x 12 <br />Spacing The measurements below are in feet-inches <br />Species Grade <br />(inches) (e.g. 9-10=9 feet, 10 inches) <br />Douglas #2 or <br />16 9-10 14-4 18-2 22-3 25-9 <br />Fir-larch better <br />Douglas #2 or <br />24 8-0 11-9 14-10 18-2 21-0 <br />Fir-larch better <br />Use this table for rafter spans with a ceiling attached, and conventional light dead loads <br />10 PSF Dead Load <br /> <br />Rafter Size 2 x 4 2 x 6 2 x 8 2 x 10 2 x 12 <br />Spacing The measurements below are in feet-inches <br />Species Grade <br />(inches) (e.g. 9-10=9 feet, 10 inches) <br />Douglas #2 or <br />16 8-11 14-1 18-2 22-3 25-9 <br />Fir-larch better <br />Douglas #2 or <br />24 7-10 11-9 14-10 18-2 21-0 <br />Fir-larch better <br />If the roof system has: <br />a. Over-spanned rafters or trusses, <br />2 <br />b. The array is over 5 lbs/ft on any roof construction, or <br />c. The attachments with a dead load exceeds 45 lbs per attachment; <br />It is required that you provide one of the following: <br />I. A framing plan showing details how you will strengthen the rafters using <br />the supplied span tables. <br /> <br />3 <br /> The Span Tables and Exhibits A-C were printed with permission from the Solar America Board of Codes & Standards. <br /> <br /> <br />