Paul
I bid a 21' x 16'  PV array on a 1.5:12 standing seam roof using the S-5 PV 
kits. http://www.s-5.com/clamps/index_686.cfm The seams were 1-1/2" high with a 
half inch folded lip on top. It seemed like a good idea to mount the modules 
using the 4-point method you suggest. 
After clamping a sample S5 to a random rib, I realized the seam, and the 
attached S5 were not sitting level. After trying several more ribs I realized 
that all the ribs were leaning slightly. It's not a problem for shedding water 
but it meant the plane of the module mounting surface was way uneven. 
I ordered Unirac Lite rails and end clamps, and ate that cost. 
Once the 16' N-S rails were attached and torqued, three of us grabbed the one 
piece rail near the ends and in the middle and after several heave-ho's managed 
to bend the ribs to align pretty close to flat across the rail tops. We checked 
with a carpenters level across each pair of rails to be sure. The were close 
enough that tightening the module clamps didn't have to pull the rails into a 
proper alignment. 
We then went back and re-torqued all the clamping screws and retightened the 
hex bolts on the assumption that they probably loosened while being man handled.
Using the S5's alone would have been a huge chore trying to straighten the 
steel ribs, was the lesson learned. It was also easier to adjust and level the 
height of the rails using the L-foot slots as opposed to the jam nuts on each 
individual S5. 
The MetlSpan ribs seem to be the same style and are mechanically crimped during 
installation. I suspect they will have the same issues.
Jim Duncan
North Texas Renewable Energy Inc
817.917.0527
[email protected]
www.ntrei.com  

  ----- Original Message ----- 
  From: Paul Lyons 
  To: [email protected] 
  Sent: Wednesday, August 26, 2009 5:32 PM
  Subject: [RE-wrenches] S-5 clamps on the standing seam roof


  Hello RE-Wrenches -

   

  We are working on the design details for S-5 clamps on a standing seam roof 
with the PV modules mounted directly on the clamps at four points (i.e. no 
horizontal rails).  The roof is made by Metl Span of Lewisville, Texas.  The 
building is in New England and the roof has a slope of 0.5:12 

   

  Have any of you had experience with these clamps and/or this particular roof 
manufacturer?  

   

  Paul Lyons, P.E.

  Zapotec Energy Inc.

  675 Massachusetts Ave

  Cambridge, MA 02139-3309

  Tel: 617-547-5900  ext.201

  Fax: 617-547-5901

  Mobile: 617-285-0634

  Email: [email protected]

   

   



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