Grain Systems Tanks PNEG-4072A - Manual (Page 85)

Chapter 7: Roof Assembly
Assembling Purlin Number 3
Purlin number 3 is located third from the bottom of the rafters.
Before You Begin
Place two roof rafters on the ground with roof panel holes facing up. Several A-frame assemblies will have
X-bracing installed and be placed periodically throughout the perimeter of the roof. Determine if X-bracing
is being installed and note those steps in this procedure.
NOTE: Temperature cables may also be installed at this location, to determine if temperature cable brack-
ets will be needed, see About Temperature Cable Brackets and A-Frame Assemblies, page 76 .
What You Should Know
The A-frame assembly consists of two roof rafters identified as the left-hand roof rafter (A) and the right-
hand roof rafter (C). The purlin configuration may not be the same on all A-frames at this location, (number
3), depending if X-bracing is being installed or not.
There are also two different purlin clips, a left purlin clip (E) and a right purlin clip (D). The left purlin clip
has seven holes, compared to the right, which has six holes along the purlin and purlin clip mating surface.
NOTE: The seventh hole location in the center of the left purlin clip (E) is for identification purposes only.
No hardware is used in this location.
1. Attach a right purlin clip (D) and a left purlin clip (E) to the right-hand roof rafter (C), and install two
flange bolts (F) and two flange nuts (I) into the two top holes.
NOTE: If no X-bracing is being installed, install three flange bolts (F) and three flange nuts (I) in this
step.
2. Attach a right purlin clip (D) and a left purlin clip (E) to the left-hand roof rafter (A), and install two
flange bolts (F) and two flange nuts (I) into the two bottom holes.
NOTE: If no X-bracing is being installed, install three flange bolts (F) and three flange nuts (I) in this
step.
3. Install the purlin (H) to the right purlin clip (D) and the left purlin clip (E) located between each roof
rafter. Install twelve flange bolts (B) and twelve flange nuts (G), securing the purlin to the purlin clips.
NOTE: If no X-bracing is being installed, proceed to step 8.
4. Attach the bottom X-brace (K) to the right-hand roof rafter (C), and install a flange bolt (F) and a
flange nut (I) into the bottom hole.
IMPORTANT: For adjustment purposes, DO NOT tighten the X-brace flange bolts until all X-braces
have been installed.
5. Attach the top X-brace (J) to the left-hand roof rafter (A), and install a flange bolt (F) and one flange
nut (I) into the top hole.
6. Secure the bottom portion of each X-brace (J and K) with a flange bolt (F) and one flange nut (I).
7. Install a flange bolt (L) and one flange nut (M) securing the X-braces together where they cross.
8. After all purlins are installed, tighten the hardware to the recommended torque specifications. See
Bolt Torque Specifications, page 24 .
Pneg-4072A 72 Ft Diameter 40-Series Bin 85