New UL 1703 fire testing requirements are proving to be a challenge for some kinds of solar installations. So say experts at Intertek and TUV Rheinland PTL, two of the main independent labs now testing solar modules and systems for fire code conformance.
The 2014 revision of the standard introduces new PV module fire type classification and system rating tests. Intertek and TUV both say they are now seeing a steady stream of systems and modules for testing because the 2014 revision of the standard introduces new PV module fire type classification and system rating tests that all rooftop-mounted systems in California must pass starting January 1 of next year. The rest of the U.S. will have to comply as of October 2016.
But some systems are having a hard time passing the tests. TUV Rheinland Engineering Manager Mark Witt says systems with polymer backsheets are having a particularly hard time passing the low-slope-roof fire test. Most require some kind of mitigation measure such as a skirt or deflector behind the panel. One difficulty with skirts is that they can actually worsen the spread of fire rather than retard it, says Intertk Engineering Team Lead Gregory Allen. Many system makers are having ot go through several design iterations to devise skirts that function correctly. And in other cases, system makers are geting creative about fire mitigation techniques and eliminating the need for deflectors at all, he says.
Though certification labs can conduct a fire test in about four hours, most systems end up having to undergo a matrix of tests to cover different configurations, says TUV’s Witt. To check out various mitigation strategies, most systems end up going through many more tests than the bare minimum, he says. Because systems end up undergoing a number of tests during certification, Witt says system makers who wait to certify products in November are likely to miss the Jan. 1 deadline.
At Intertek, Allen says the backlog for fire certification testing is currently about two weeks. He also emphasizes that the introduction of mitigation techniques can sometimes impact system designs in ways that are hard to foresee. That is one reason Intertek has seen its slate of solar system tests explode, he says.