Solar power’s increasing prominence makes risk assessments more important than ever
Rooftop photovoltaic (PV) installations are becoming increasingly popular as more businesses choose to generate some of their own electricity. Solar panels and sustainable power systems have become more affordable and easier to install over the years. Plus, government incentives supporting clean energy have created more opportunities for businesses to explore the technology.
More PV installations means more risk of rooftop fires. There were 56 solar fires in 2018, a 36% increase compared to 2017 and a 124% increase compared to 2015, according to PV magazine.
The rapid expansion of PV installations has created unforeseen technical and fire service challenges, forcing building codes and fire service tactics to evolve. Separate standards applying to individual components of PV systems now take a systematic approach to fire safety. They address not only the photovoltaic modules and panels together, but all other related components, as well as the rooftop materials to optimize fire safety in all conditions.
Article 690 of the National Electrical Code (NEC/ NFPA 70). This addresses the primary electrical safety requirements for PV installations. In addition to common electrical system requirements like using listed equipment and providing overcurrent and ground fault protection, the NEC requires a clearly marked, accessible means of disconnecting the generating panels from the inverters. The disconnect must de-energize all equipment more than 1 ft (0.3 m) from the solar modules. This minimizes exposure of emergency responders to high voltage and should be located outside the building and at ground level to maximize accessibility wherever practical. Further, where there are multiple panel arrays, NEC requires posted diagrams to clearly indicate what each switch controls.
ASTM E108. Roof covers are tested to ASTM E108 to determine their resistance to external fires, like burning materials falling on a roof from a nearby building or forest fire. It classifies roofs as Class A, B or C, with Class A being effective against severe fire exposures, Class B for moderate exposures, and Class C for light exposures. Building codes normally require Class B roofing only in dense urban areas, with Class C roof covers permitted almost everywhere else. Class A roofs are usually required only in areas exposed to wildfire.
UL 1703. Both the National Electrical Code (NEC) and International Building Code (IBC) require PV panel installations to be listed per UL 1703. Prior to 2013, PV panels/modules were tested without an underlying roof cover, but are now required to undergo five fire tests, four of which place the ignition source between the roof cover and the panels/module. These tests show that roof cover fire resistance is always worse when panels are installed over the cover. Only more expensive, glass faced panels can pass the Class A and B fire tests, so they are not always the first choice.
UL/IEC 61730. This has been developed to address standard PV panel module installations. Most panels/modules that are listed per UL/IEC 61730 also meet UL 1703 requirements.
Managing the fire risks associated with PV systems is a critical part of any property risk management program. Property losses can be devastating to organizations, which is why it is essential to work with a team of experts that has a deep understanding of the fire and explosion risks associated with solar power and sustainable energy.
Engineers from TÜV SÜD Global Risk Consultants understand the critical details of PV installation, like making sure they are not installed over critical production equipment, providing safe access pathways for fire fighters, ensuring that electrical cables are covered, and ensuring that different levels of roof have proper protection from fire risk. Our engineers provide sound, cost-effective Fire Protection Engineering to address today’s newest challenges in fire and explosion property loss prevention coupled with increased competitive demands.
Manage the fire risks associated with PV systems