In our area of California, when the green grass dies and turns brown, the area under any type of array needs to be free of grass. An array could ignite a wildfire if the array were emit sparks. This is a very rare condition but it can happen to even the best design and module type.
There would not be any brush anywhere near an array. 10 feet from any point of the array makes sense but if there were a wildfire I would want alot more. 100 feet is typical for the zone around a home. That is what our AHJ wants to see in an inspection. We are in a very dangerous area for wildfires in the southern Sierra. Brush does not count as grass. An array should survive a grass fire. Brush would be much more dangerous and must be kept clear as it is a much larger heat source than grass. I hope this is helpful. Dave Angelini Offgrid Solar "we go where powerlines don't" http://members.sti.net/offgridsolar/ [1] e-mail [email protected] [2] text 209 813 0060 On Fri, 20 Mar 2020 17:06:01 -0600, Dan Fink wrote: Hello esteemed Wrenches; I am trying to clear this up for a client and his AHJ, which is also puzzled at how to interpret IFC 2018, Section 1204.4, which states: Setback requirements shall not apply to ground-mounted, free-standing photovoltaic arrays. A clear, brush-free area of 10 feet (3048 mm) shall be required for ground-mounted photovoltaic arrays. I found one lone informational note in a white paper stating this was to prevent a burning PV array from igniting surrounding vegetation and the fire spreading. So, has anyone dealt with an AHJ on this before? Our questions are: * What exactly is a "free-standing photovoltaic array" that is exempt? A pole mount? Couldn't burning debris from that ignite vegetation underneath? * What exactly does "A clear, brush-free area of 10 feet (3048 mm)" mean? "10 feet" is a linear measurement, not an area, that would be in square feet. * What is "brush"? Does grass count as brush? I would interpret this on the safe side as meaning that all vegetation under the PV array and out to a 10 foot perimeter should be cleared, except for pole-mount arrays (that exception makes no sense to me). I always recommend to clients that the area _under_ the ground mount array should be pea gravel bordered by railroad ties, but out to 10 feet from the array edge seems excessive. Any input greatly appreciated! Dan Fink Executive Director, Buckville Energy Consulting NABCEP PV Associate NABCEP Certified PV System Inspector IREC Certified Instructor(tm) for: ~ PV Installation Professional ~ Small Wind Installer NABCEP Registered Continuing Education Providers d [3][email protected] [4] 970-672-4342 Links: ------ [1] http://members.sti.net/offgridsolar/ [2] mailto:[email protected] [3] mailto:[email protected] [4] mailto:[email protected]
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