An important design consideration when considering a rooftop solar system is for the roof system to have an expected
service life equal to or greater than the solar system. This helps minimize the need to dismantle or remove the solar
system to provide for necessary repairs or complete removal of the roof system to maintain building watertightness.
Solar systems often are reported to be manufactured to have a service life of 25 years. Specific service life
information is available from individual solar system manufacturers. Roof systems, on the other hand, have service
lives that vary significantly depending on the specific roof system design, roofing materials used, installation
workmanship and building owners' maintenance. Although some roof system types—such as slate, clay tile and
copper architectural metal panel—have been known to have service lives of 50 years or more, other roof system
types have significantly shorter service lives.
Based on this, NRCA has concluded above-average roof systems should be installed on buildings where rooftop-mounted solar systems are being installed or where rooftop-mounted solar system installation is anticipated in the future. NRCA's recommended enhancements to help ensure roof systems will have service lives equivalent to or greater than the anticipated service lives of the rooftop-mounted solar systems are provided NRCA Guidelines for Rootop-mounted Photovoltaic Systems, 2015 Edition. The publication contains NRCA's best practices for rooftop-mounted solar systems, including applicable code requirements. Information from the 2015 editions of the International Building Code, International Residential Code, International Fire Code and NFPA 1: Fire Code, and the 2014 edition of NFPA 70: National Electric Code also are included. This valuable technical resource is complemented by figures graphically depicting building code requirements and illustrating proper solar system installation.
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