What is the weight per square foot that the RapidRac?
I'm looking for the Unirac RapidRac specification. What is the maximum load that Rapidrac will support?
Comments
It's a hard question to answer, because it depends so heavily on environmental variables. The Code Compliant Installation Manual -click here (pdf) outlines the "Procedure to Determine Wind Design Load," and also details the equations to find the various forces acting on the product.
With respect to maximum stresses the product can handle, please see the following from said manual:
"The maximum allowable uplift load force in the Z Direction is 1240 lbs with respect to the ballast frame to rail bracket attachment. The maximum allowable uplift force in the Z direction for RapidFoot is 1200 lbs."
and
"The allowable lateral load force in the X direction is 1240 lbs with respect to the ballast frame to rail bracket attachment. The allowable lateral load force in the X and Y directions for RapidFoot is 1200 lbs."
-Page 11
I think Clean Energy WI is curious about the actual weight of a RapidRac array. While it's still a difficult question to answer generally, we can use an average to illustrate the range of weights.
Unirac's RapidRac sales brochure states that the product "can be installed as light as 2lb/ft2 with many penetrations, or may be installed with zero penetrations (with higher roof loading)." The total ballast weight, however, can vary greatly based on environmental variables.
The Manual uses a 10 by 10 array, requiring 500 blocks total ([10x10]x5) (page 13). The Manual suggests using Solid Cap Concrete Blocks weighing 26 pounds (page 16). Assuming you're using the REC 225PE RapidRac mount, which has a footprint of 56.5"x66", a 10x10 array would have a total footprint of 47'x55', or 2,585 ft2.
The total ballast weight would be 13,000 pounds, the total racking weight would be 1,200 pounds, and the total module weight would be 4,000 pounds, for a total weight of 18,200 pounds.
18,200 pounds over 2,585 ft2 yields a psf weight of 7 pounds.
As you can see, 2 to 7 is quite the range, and greater weights are not infeasible in windy parts of the country. Nonetheless, I'm hopeful this'll provide some guidance as Clean Energy WI discusses RapidRac as an option with their customers. Thanks for reading!
Comments
It's a hard question to answer, because it depends so heavily on environmental variables. The Code Compliant Installation Manual -click here (pdf) outlines the "Procedure to Determine Wind Design Load," and also details the equations to find the various forces acting on the product.
With respect to maximum stresses the product can handle, please see the following from said manual:
and
leventbas,
I think Clean Energy WI is curious about the actual weight of a RapidRac array. While it's still a difficult question to answer generally, we can use an average to illustrate the range of weights.
Unirac's RapidRac sales brochure states that the product "can be installed as light as 2lb/ft2 with many penetrations, or may be installed with zero penetrations (with higher roof loading)." The total ballast weight, however, can vary greatly based on environmental variables.
In the RapidRac Code Compliant Installation Manual, Unirac uses an average of five ballast blocks per module, so I will as well.
As you can see, 2 to 7 is quite the range, and greater weights are not infeasible in windy parts of the country. Nonetheless, I'm hopeful this'll provide some guidance as Clean Energy WI discusses RapidRac as an option with their customers. Thanks for reading!
Thank you for the clarification tom!
Does the thread answer your question Clean Energy WI?