Forensics related to metal wall installations is used to explain what determines visual acceptance.
Panel Fabrication Tolerance
- Length
- Squareness
- Viewed from front
- Measured across sheet
- View from panel side
- Measured across sheet
Panel Installation Tolerance
- Panels to be installed:
- True to line and level/plumb
- Exposed fasteners shall be installed in a straight line
- Field Measurements
- Panel shall be measure with panels positioned without restraint and with enough support to prevent significant distortion or deflection
- Substrate must be straight and true
- Panels should be progressively installed so that overall misalignment or tolerance issues are not focused in a single panel on a wall
Panel Finish
- Surface imperfection
- Dents, dimples, and defects from manufacturing (coil breaks, fluting, camber)
- Paint finish and color tolerances and performance values
Panel Deflection
- Can be caused by environmental factors (wind)
- Sub-structure tolerances and movement
- Allowable deflection by code L/60
- (IBC Table 1604.3)
Panel Face Distortion – Perceived Oil Canning
- Can be caused by all previous identified factors
- Percieved oil canning is not considered a cause for rejection (see MCA document)
- Effects of thermal movement
- Clips, slotted holes, panel breaks
- Types of material (steel, aluminum, natural metals
- All have differrent expantion and contraction values
- Steel 1/16″ in 10′-0″/100° of temperature change
- Aluminum 1/8″ in 10′-0″/100° of temperature change
- All have differrent expantion and contraction values
