b',,.,-\'4esigning Ahead:LifeCycles - Roofs - WarrantiesCodes and Standards Photovoltaicsay their PVs have aservice life. GlassThe primary safety and wiring code for PVs isver bycleof manufacturerslongco edArti 690 module manufacturers claim their solar modules will produce energy for 30- the Nation Electric(NEC), which addresses safety requirements for alCode 50 years. Many thin-film PV manu routinely say their modules willthe installation of PV systems. The latest versionis NEC 2008; however, facturers generate 80 percent of the modules\' installed power production at year 20 ormany localingmay stillusing NEC 20 .t p build codesbe02 or 2005 Bes rac25.tice would be to use the2008. T NEC covers everything from module NEChe When designing ait isto keep in mind the longinstallation, wiring, and grounding to connector boxes and inverters. The solar project.important service life of PVsin relation to the type of roof system being designed.bestsource to learnmoreaboutPVandtheNEC canbefound at Chances are,roof will have to be replaced long before the PV moduleswww.nmsu.edu/-tdi/Photovoltaics/Codes-Stds/PVntheecSugPract.html.6 do.it make economic sense to install an existing roof system with aPer and safety standards for individual solar componentsthe Doesformancein limited performance life? What is required to m the roof? Wh can beUnited States are set by Underwriters L r ories Inc.L T benchmark aintainatabo at (U ).he done to extend the roof\'s service life? Was the cost of removing the PV mod UL standards are: ules for roof repairs or replacement in the future factored in, and is the ownerUL 1703 formodules. PV awarethe futu cost?UL 17for solar inverters. ofre41 Flexible thin-film PVand composite-paneled crystalline systemstheAllshould carry a ULIn most cases, one cannot receive havecomponentslabel. advantage of direct attachment to the roof membrane or onto the elastomericinc tives and rebates for array systems th have not beenUL-certified. en at coating system. Thin-film modules can last longer than the roof systems.(Certification cancome from other test facilities but will still use the UL One option developed by SolarPower Restoration Systems combines elas benchmark standards.) tomeric coating with PV modules, creating awaterproof system. Recoat T performance standard for solar mo the Standard Test Condinewhedules is compatib standard enchmarkmodule ing the elastomeric coating solar composite system with ale elas tions (STC), and is aizedtest to factory-b PV tomeric coating insynchron service life of the roof with thep output. Allshouldve an STC rating on the produ label. the futureizes theowermodulesha ct PVles.Using the STC means th amodule c produce Xt of watts modu atsolaranamounDo not forget to contact the roof manu if the existing roof is stillunder thetest conditions. In the realan installed solar module facturerSTCworld, un warranty.jor modification and changes to roof use can void anywill notdu the STC-listed power. derMa pro ce ft7 w nty if the manufacturer is n contacted first and agrees to theManufacturers are starting to sell plug-and-play, p s ar arrays. xistingarra otackagedol~olar installation. It is important to monitor any solar array rack-mountedThe package might say it is akW-DC system und .reality, 50er STC Inactual installation for damage due to construction and foot traffic.power production of the array is dependent onthe system is installed where In the roofing industry, we areto specifying awarrantyandhow the system is designed. Global location, solar orientation, solar usedsingle-source covering all compon iallacement,workmanship for15,shading, length of power cable runs, wiringandr-to-AC conents, mater rep and10,size,inverte DCor 20 years.rently,ngle-source PV roof-system w do not exist.version rating all play a role intual AC power output toe. A Cur si arrantiesac th consumerPhotovoltaicwill have two warranties. One wa is for materialgood rule of thumb is to use 75%-77% of therating tone actual modulesrrantyDCdetermiand workmanship d for manufacturing the PV module. The warrantyAC power output. AkW-DC s em m only p duce 37.5 kW-AC or efects50yst ightrothe can be as short as 18 months, butaverage warranty is five years for PVeven less. module replacement due to defective materials/labor. The second warranty is for power production. Most manufacturers will guarantee their module willFire and Wind Ratings and Codes generateof the installed rated power p ion at year ten and 80Withexceptions,t PV modules are fire-rated UL Class C. O a 90 percentroduct fewmos nly percentthe installed rated power production at year 20.average, ahandful of PV modules have been rated UL Class A. L up the1703 ofOnPVookUL module will lose 0.5 to 1.0 percent of its installed rated power production ainformation on amodulecross-reference it to findwhat thePVandoutsysyear.tem fire rating is. F assemblies are difficult totermine. Many thinire ratingdetoowe membra assem liPhotovoltaic inverters-devices that convert DC powerAC p r- typ film modules on single-plyneb es are outdated and are no icallywarranted for five to ten years, and over the course of the PV array\'slong ornot been tested. areer effectivehave servicelife,they will have tobereplaced.On wiring andcabling, codeIt is important tohave both the roofing and PV manufacturer provide requires U r cable.tare warranted for tenyears (mate approvals. UL has been flexible inmeand has allowed UL Class C L- atedMos cablesto 20so cases rial only), and it makes good sense to install cables in amodulec to a UL Class Aassembly, accep thesyspremanufacturedatta hmentrooftinghybrid cable channel to protect the wiring. Therefore, with an average roof systemtem asClass A. Thischange in thefuture; UL started atest ULmaynearnew and PV system, there wilrafrom one manuf tu and sev study tohow these hybrid-rated systems really perform. This isresult beroof warrantyac rerseethe modu componentAsnalco cernsfallin torooeral warranties from the PVlemanufacturers.traditio of California fire marshals\'n with burning embersg on af. roofing manufacturers create standardized solar roof systems, we will even Thesults of this new study will determ ifisisin re ineth practiceacceptable tually get a-source warran package.the future. single ty One of thethe roofing c is, "Is the most common questions fromommunity (0solar array rated FM -90?" So far, it seems Factory Mutual (FM) has not 1Continued on page 16 15'