INSURANCE INSTITUTE FOR BUSINESS & HOME SAFETY ROOF INSPECTION GUIDE COMMERCIAL ROOF-MOUNTED BALLASTED PHOTOVOLTAIC (PV) WIND PROTECTION ON LOW-SLOPED ROOFS Use the fllwing guidance t cnduct baseline and pst-event inspectins.
Phtvltaic Wind Prtectin Guidance Large-scale cmmercial PV arrays are becming increasingly cmmn, with significant grwth in bth rf-munt and grund-munt systems. Rf-munted systems n large flat rfs are particularly attractive as they ccupy largely unused space n the rf f a building. This dcument addresses wind-related cncerns fr ballasted rf-munted cmmercial PV arrays with rigid panels installed n built-up (BUR) r membrane rfs. Ballasted PV system designs must cnsider bth wind uplift and mvement due t wind lads. Mst systems are engineered based n wind lads derived frm small-scale mdel tests that are frequently peer-reviewed. Hwever, there is n cnsensus n perfrmance criteria regarding hw much uplift r sliding is acceptable. Cnsequently, the amunt f PV mvement allwed may vary greatly. When a PV array is first installed, a baseline inspectin shuld be cnducted and the lcatin f key elements shuld be clearly identified. Fllwing a strng wind event with wind speeds exceeding the greater f 70 mph r 70% f the design wind speed f the building prvided by ASCE 7-10 r later steps shuld be taken t identify and address any change r damage that may have ccurred due t the wind event. While this dcument fcuses n wind-related issues, IBHS strngly recmmends business wners with rf-munted PV arrays pre-plan fr fire, including pre-planning with the lcal fire department. Design Cnsideratins Rf-munted ballasted PV arrays are nt recmmended in hurricane-prne areas. In additin t increased vulnerability t uplift and slippage due t greater wind lads, the ballast weight needed t resist wind lads in hurricane-prne regins can exceed the building s riginal rf design lads unless the rf was designed t handle this type f PV system. Grund-munted PV systems are preferred fr hurricane-prne regins, fllwed by rf-munted structurally attached installatins. Ensure the rf deck can supprt the increased PV arrays lads, including live lads such as rain, snw (including snw drifts), etc. Ensure the PV array being installed has been designed using wind lads frm either ASCE 7-16, SEAOC PV2-2012, r a mdel-scale wind tunnel study that meets the requirements f ASCE 49-12. Insurance and Damage Cnsideratins Wh wns the PV system? Wh insures the system prperty and liability? Wh is liable if the PV system damages the building and/r cntents, directly r indirectly? What is cnsidered PV array and rf cver damage? When are repairs cnsidered necessary? What are the expectatins f maintenance after a strm? Wh will cnduct the inspectin and make necessary repairs? Wh is physically and financially respnsible fr returning the ballast/array back t its riginal lcatin? ROOF INSPECTION GUIDE 2
Initial Inspectin Create a Baseline fr the Rf Cver s Physical Cnditin Rf Cver Cnditin Phtgraph and dcument the rf cver prir t any wrk being dne fr a PV array installatin and review the rf cnditin findings in detail with the manufacturer/installer. Pay special attentin when dcumenting the cnditin f the fllwing aspects f the rf system: Fr built-up (BUR) and mdified bitumen rf cvers, check fr bubbles, ripples, and tears, and ensure aggregate stnes are well embedded in asphalt fr BURs. Fr fully adhered single-ply (SPM) membranes, check the quality f the adhesin, lking fr ripples, tenting and tears. Fr mechanically attached SPM membranes, make sure plates and screws are prperly recessed and nt backing ut and that the membrane is well sealed arund the plates and des nt have tears. Nte insulatin r cver bard cnditin arund crickets and any ther rf discntinuities. Als nte any depressins, standing water, and grwth f mld r vegetatin. Check cnditin f draining system interir drains and gutters. Examine transitins t vertical surfaces curbs, parapets, etc. Walk the rf with the installers verifying the rf cnditin, including presence f existing rf-munted equipment. Nte needed buffer znes between the array elements and ther equipment. Identify whether the PV system will restrict the flw f water t any interir drains. CLIPS WIRE AND/OR WIRE MANAGEMENT SYSTEM PV PANEL AND FRAME CONDUIT COMBINER BOX BALLAST BAY SLIPSHEET STRAPPED, BALLAST BLOCKS NOTE: These drawings are fr illustrative purpses nly. There is a wide range f ballasted designs that include features similar t thse shwn here. ROOF INSPECTION GUIDE 3
PV Installatin CREATE A BASELINE FOR THE PV INSTALLATION PV ARRAY Precisely mark the lcatin with paint r a waterprf marker, including: Entire array lcatin. Deflectr lcatins. Each ballast lcatin. Slip sheet lcatins. Any ther tuch pint f the array t the rf cver. Cnnectr bxes. BALLAST Inspect and dcument the cnditin f the ballast (cncrete blcks and capstnes can deterirate ver time). Nte whether ballast items are strapped t the ballast bays. IBHS recmmends strapping. ARRAY STRUCTURAL INTEGRITY Inspect the metal frame f the PV panels and the supprt system t ensure there is n defrmatin. Check individual panel securement: Inspect clips/screws hlding panels. Lk fr clips that are disldged and/r nt hlding panels prperly. Electrical Cnnectrs BOXES, WIRING, AND CONNECTIONS Dcument the lcatin, cnditin, and securement methds f electrical equipment. Ensure ends f flexible cnduit and wiring are well secured t the array structural frame. NOTE: This drawing is fr illustrative purpses nly. There is a wide range f ballasted designs that include features similar t thse shwn here. ROOF INSPECTION GUIDE 4
Pst-Event Inspectin Recrd Damage Caused During Wind Events Rf Cver Cnditin ROOF COVER, ROOF DECK, AND DRAINAGE Nte any changes in the rf cver, including rf cver tears in all areas, paying clse attentin t: Rf edges. Seams (fasteners and plates). Areas near rf-munted equipment. Nte any insulatin bard depressins. Identify and immediately crrect any drainage system blckage r damage. Recrd any structural deck depressins. PV Installatin Rf cver tear created by PV array during IBHS testing f PV arrays Inspect fr signs f uplift and sliding mvement. Damage may nt be initially evident, but it can be additive ver time. With each strm, re-inspect and dcument the findings: Lcatin f individual ballast supprts. PV arrays ften d nt mve unifrmly; certain prtins may have significant mvement, while thers have little t n mvement. Array damage. Ballast mvement and displacement f any ballast blcks. Slip sheet lss, mvement, and tears. Inspect the physical cnditin f the ballast. Lk fr any deteriratin r crumbling f the cncrete blcks/capstnes. This type f ballast can deterirate due t nrmal weathering. Determine array structural integrity by lking fr: Frame defrmatin. PV panel damage. Examine individual panel securement. Inspect clips, screws, and blts hlding panels. Lk fr bent clips. Lk fr blts and clips that are disldged r nt hlding panels prperly. Electrical Cnnectrs BOXES, WIRING, AND CONNECTIONS Displacement f cnnectr bxes/pwer distributin equipment. Lse cnduit and wiring. Lse cnnectins. Obvius signs f damage t the electrical wires such as frays, nicks r cuts. Flexible cnduit r wires that n lnger prvide slack fr additinal mvement in a future event. System cmpnents that are encraching needed buffer areas arund ther equipment. Ballast Bay Frame Slar Panel Frame Slar Panel Frame Undamaged Clip Illustratin f an undamaged clip and a bent clip Ballast Bay Frame Bent Clip ROOF INSPECTION GUIDE 5