Installation Guide

Page
12
Unirac Code-Compliant Installation Manual SunFrame
R
1411 Broadway Boulevard NE
Albuquerque NM 87102-1545 USA
Step 4: Select Rail Type:
Selecting a span affects the price of your installation. Longer
spans produce fewer wall or roof penetrations. However,
longer spans create higher point load forces on the building
structure. A point load force is the amount of force
transferred to the building structure at each connection.
It is the installer’s responsibility to verify that the building
structure is strong enough to support the point load
forces.
Step 5: Determine the Downforce Point Load, R (lbs),
at each connection based on rail span:
When designing the Unirac Flush Mount Installation, you
must consider the downforce Point Load, R (lbs) on the roof
structure.
The Downforce, Point Load, R (lbs), is determined by
multiplying the Total Design Load, P (psf) (Step 1) by the Rail
Span, L (ft) (Step 3) and the Module Length Perpendicular to
the Rails, B (ft).
R (lbs) = PLB
R = Point Load (lbs)
P = Total Design Load (psf)
L = Rail Span (ft)
B = Module Length Perpendicular to Rails (ft)
It is the installer’s responsibility to verify that the building
structure is strong enough to support the maximum point
loads calculated according to Step 5.
Table 8b. L-Foot SunFrame Series Rail Span (uplift and downforce)
51015202530354045505560657075808590
2SFSFSFSFSFSFSFSFSFSFSFSFSFSFSFSFSFSF
2.5SFSFSFSFSFSFSFSFSFSFSFSFSFSFSF
3SFSFSFSFSFSFSFSFSFSFSFSF
3.5SFSFSFSFSFSFSFSFSFSF
4SFSFSFSFSFSFSFSFSF
4.5SFSFSFSFSFSFSFSF
5SFSFSFSFSFSFSF
5.5SFSFSFSFSFSF
6SFSFSFSFSFSF
6.5SFSFSFSFSF
7SFSFSFSF
7.5SFSFSFSF
8SFSFSF
8.5SFSFSF
9SFSF
9.5SFSF
10 SF SF
10.5 SF
11 SF
11.5 SF
12 SF

= Distributed Load (plf)
Span
(ft)
Table 8b. L-Foot SunFrame Series Rail Span (side load)
*Note: P
net
uplift will be a negative number