Looking to estimate the number and size of rails for your solar system and determine the number of solar rail mounts needed for your specific location?
The easiest way is to use the Unirac U-Builder tool since we primarily sell Unirac railing equipment for solar mounting.
In Unirac's tool's "Design It" section (see linked example below), there is a calculator that will take your zip code and let you know what your span calculations are. For example, if you punch in 94043 (Renvu's Zip Code), it will tell you some information such as wind speed and snow loads in the area. Based on this it will calculate what your allowed rail spans are for that area. In this example, we could use Unirac Solarmount LT (Unirac light rail) with a maximum span of 72 inches (or "6 foot on center"). If you wanted to use Unirac SM (Unirac standard rail) or Unirac HD (Unirac heavy duty rail) you could, but it may be unnecessary and up to the installers/designers discretion.
By default, we typically design solar systems to be a 4 foot on center design with Unirac light rail. This usually covers most of the United States and allows for a stronger solar racking system and leaves room for design/installation error. Solar railing systems that push the design limits may require additional design considerations such as staggering the posts so that there aren't multiple attachments on a single rafter.