[RE-wrenches] Racking System - Identification Help
Dave Click
daveclick at fsec.ucf.edu
Thu Jun 26 10:12:27 PDT 2014
As an update- the system used at this install turned out to be a
currently-available product called SolAttach:
http://www.solattach.com/
On 2014/6/3, 11:11, Dave Click wrote:
> Jason, thanks for the comment! I agree that systems could connect to
> just sheathing and stay on the roof- I think Zilla has a product that
> does this too. My concern about wind resistance stems from the fact
> that there appeared to be an engineer's stamp on the Unirac calcs with
> lag screws and then something completely different was installed in
> the field. It's likely that this installer has used this same mounting
> system in windier coastal areas so hopefully their fastener selection
> had some informed analysis... I didn't see any, though.
>
> And to be clear, I'm not looking to overrule another PE if it is in
> fact an engineered system and it's just that the wrong set of plans
> got submitted to the building department.
>
> DKC
>
>
>
> On 2014/6/3, 10:12, Jason Szumlanski wrote:
>> Dave,
>>
>> I can't identify your hardware, but I just wanted to comment on your
>> comment about hitting rafters. There are products out there that can
>> obtain the requisite load ratings without connecting directly to
>> structural members. We have had systems engineered and permitted
>> using Ecofasten products on low-slope roofs that fasten only to wood
>> sheathing or metal roof materials in 170 mph zones in Florida (ASCE
>> 7-10, FBC 2010). I'm not an engineer, but I've been told if there is
>> adequate data on pull-out and shear, you can use that data to
>> properly design a system without hitting rafters with the right
>> number of attachment points. I don't like the looks of what you
>> pictured, but it's plausible that it was an engineered system design.
>> The permit drawings not matching... that is another story...
>>
>> If, for example, each of the six fasteners provide 100 pounds of
>> pullout strength with a safety factor, that would be good for 12 sq
>> ft at 50 spf uplift per attachment. 250 fasteners would be good for
>> about 5kW of solar.
>>
>> Jason Szumlanski
>>
>> Fafco Solar
>>
>>
>> On Tue, Jun 3, 2014 at 9:06 AM, Dave Click <daveclick at fsec.ucf.edu
>> <mailto:daveclick at fsec.ucf.edu>> wrote:
>>
>> Hi all,
>>
>> Anyone know what this racking system is? The permit drawings say
>> Unirac with lag screws and Eco-Fasten flashings, which this
>> pretty clearly isn't. I'd never seen this before, and I imagine
>> this wind resistance is not quite the 140 mph that the installer
>> claims it is. Of the ~250 wood screws holding this system down
>> into the roof, I think six of them accidentally hit rafters.
>>
>> Thanks!
>> Dave
>>
>>
>>
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>
>
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