FX Rail-Less Engineering

FX Engineering & Design Guide
IRONRIDGE CONFIDENTIAL
Page 7 of 21
3.2 Determine Maximum Allowable Spans & Cantilevers
Definitions
Span: The distance between two adjacent Mounts, measured at the center of the hanger bolt.
Cantilever: The section of a module extending beyond a Mount.
Use the Span Tables (Appendix A) to determine maximum allowable spans and cantilevers.
• Maximum Span is a function of (5) factors: Wind Exposure Category, Wind Speed,
Roof Slope, Roof Zone, and Module Orientation (i.e. portrait or landscape).
• Maximum Cantilever = 1/3 of Maximum Span
Tip!
Record your span and cantilever values for the respective roof zones in a table:
RZ 1
RZ 2
RZ 3
Max Span (in)
Max Cantilever (in)
3.3 Layout Modules on Roof
Layout the modules on the roof, noting which roof zone(s) each module is occupying.
If there is flexibility in the module layout, it is best to:
• Keep all modules in Landscape orientation
• Keep modules out of Roof Zone 3
• Minimize the number of modules in the Roof Zone 2 regions
Spacing Between Modules
To accommodate the FX System hardware, the spacing between modules along a row (E-W
direction) and between rows (N-S direction) is ½” and ¾”, respectively.
Proximity to Eave and Ridge
The Trim extends another 4.5” from the southern edge of the module. The Trim must not
extend beyond the roof eave.
Modules can be placed up to 7-8” from the roof ridge.