[RE-wrenches] Hurricanes and Wind-loading !

Dave Angelini Offgrid Solar offgridsolar at sti.net
Wed Sep 13 11:22:12 PDT 2017


I have 2 clients in the Keys and one on the mainland who basically hired
me to make sure they had AC and AC cooling, no matter what.
It is an Offgrid mentality where you don't put holes in a roof and use
ground mounts for solar. You have a battery system and a 500 gallon
propane tank/generator along with an energy sipping mini-split heat pump
or 2. A 2,500 gallon water tank and a decent pantry.

I lived there for a year and I am not sure if staying during a hurricane
or living there without cooling would be the hardest :)
 --Dave


Dave cwarfelDave
> I am wondering if this will change the perspective of Florida utilities,
> regulators, and property owners with respect to distributed generation
> and resiliency.  The stories of people coming back to structures with no
> power and Florida's hot weather is not helping people function in the
> climate.  I realize ac is not a first thought option, but there are
> other cooling options.
>
> Assuming the array is intact, it makes sense to use battery technology
> instead of having a high dependency on generators that rely on fuel that
> may not be available. Past experience shows that roofs with arrays or
> collectors fare better than those without, all things being equal. The
> racking system ties the roofing frame together so it acts more as a
> monolithic structure thanwithout. This increases the ability to resist
> uplift and downward forces. Any data would be appreciated.
>
> Chris
>
>
> On 9/12/2017 10:14 PM, Tom Lane wrote:
>> Windloading MAPS of Florida depend on how close you are to the coast
>> and ground mounted versus say on top of a high rise near the beach and
>> how close you are to the wind zones . The one factor you cannot get
>> away with is directing clipping panels to metal roofs . You must use a
>> rail that holds all the panels to the rails instead of the simple
>> metal roof clips . The one important feature to control wind loads is
>> to use three rails on two end modules on each end of an array AND 1/2
>> set extra of mounting hardware on ALL two end modules . On a raise
>> array on a flat roof you should X brace the last three on each end .
>> Always stay 3 feet minimum away from hips , gable ends , valleys ,
>> eves and ridges . Use 3/8 "SS attachments instead of 5/16 " and always
>> hit or attach to trusses and tie all trusses together with a five
>> pattern ( like on dice 🎲) instead of a four pattern which skips every
>> other truss . However any Hurricanes  over 175 MPH moving slow will
>> take everything out to the slab  , but if correctly installed, then
>> when the homeowner finds parts of their home the panels will  be
>> holding that part of the roof in one piece. GatorTom
>>
>>
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>
> --
> Christopher Warfel, PE
> Entech Engineering, Inc.
> 401-466-8978
>
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Dave Angelini Offgrid Solar
"we go where powerlines don't"
http://members.sti.net/offgridsolar/
e-mail  offgridsolar at sti.net
text 209 813 0060




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