EJOTs are a German product designed for this kind of application. They have an application note that discusses purlin thickness, thread size, and pull out strength. Mudge Fasteners carries them in the US.
Jeff Irish, PE President Hudson Valley Clean Energy, Inc. and Adirondack Solar 13 Hook Road Rhinebeck, NY 12572 T.845.876.3767x110 F.845.876.3912 j...@hvce.com<mailto:j...@hvce.com> Solar Electric Systems NYSERDA Eligible PV Installer NABCEP Certified PV Installer NABCEP Certified Technical Sales Professional From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of toddc...@finestplanet.com Sent: Thursday, March 15, 2012 3:51 PM To: RE-wrenches Subject: Re: [RE-wrenches] No underside access metal biulding attachment i think bob o once said he used ss pop rivets on a job like this. todd On Thursday, March 15, 2012 9:26am, "lars Ortegren" <l...@cal-solar.com<mailto:l...@cal-solar.com>> said: Wrenches, We have a project coming up where we are installing a large array on a low slope metal building with metal purlins. Typically we would through bolt our attachment to the purlins, but in this case the building is a self-storage, and access is not an option. Does anyone out there have experience with any top side only metal-metal attachments? I’ve thought about using some larger sized stainless self-tapping screws, but I worry about the pull out strength (as the roof combined with the c-channel purlins are only about 1/8”) and the effects of heat and cooling of the roof backing the screws out over time. Any thoughts ? Lars Ortegren Director of Operations California Solar Electric Company 10141 Evening Star Drive, Suite 6 Grass Valley, CA 95945 http://www.californiasolarco.com/ Phone : (530)274-3671 Fax: (530)274-7518 California C-10 Electical Contractor #779624 NABCEP Certified PV Installer # 091110-89 Certified NABCEP Continuing Education Provider More about NABCEP: http://www.nabcep.org/ Sent from Finest Planet WebMail. -- This message has been scanned for viruses and dangerous content by Hudson Valley Computer Services<http://www.hvcomputerservices.com/>, and is believed to be clean.
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