Solar mini rails are a relatively common PV mounting solution that offers cost effective installation of solar modules onto trapezoidal metal roofs.
This method uses small rail sections in specific areas as needed along the roof – reducing the total length of rails. They have benefits which make them desirable to contractors and installers. They provide material and shipping cost savings to the customer when compared to rail systems. In addition, they are small, which allows them to be handled easily onto roofs. Additionally, mini rails can be installed with just a couple of fasteners – potentially cutting installation times compared to rails.
| Solar mini rail | Long rail systems |
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While there are two main concerns with solar mini rails: both concerning uplift loads.
1st Concern: Direct Pull-Out vs Shear Load
A major issue is the way mini rails are fastened straight into the top of the roof ribs. Due to this fastening method, the uplift loads that the solar panels produce result in the fasteners experiencing direct pull-out load.
2nd Concern: Non-Concentric Load
Although the mini rail attaches with two fasteners, the point of load is never concentric to them. The grab of the mini rail is never at perfect center on the rail, so the uplift load that is going through the grab is not evenly distributed between the fasteners.
The solution to such problems is one of the two below:
1)Add the quantity of mini rails, and add a factor of safety; however, this will also greatly increase the cost.
2)Use a bracket that can mount the grab over a single rib, fastening into the sides, so that the fasteners are in shear—not direct pull-out.
| Add the quantity of mini rails | Use a bracket |
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ART SIGN offers both rail and rail-less solar mounting solutions for metal roofs. Explore our line of brackets for rack and rail systems. Thinking of going rail-less? For any inquiry for solar panel mounting system, pls contact us, E-mail:sales@artsign.net.cn , Whatsapp / Wechat / Skype: +86 18030235875, thank you.