Anytime a rack user wants to change their bay profile or loading, the rack should be reviewed by a qualified engineer to ensure that the new proposed configuration is still RMI compliant. This includes adding frame extensions that increase the height of the storage rack.
Adding frame extensions can be a problem even if the total load in the bay is not increased. When shelves are moved upward (raised in elevation) the strength of the framing structure is affected. Also the addition of the frame extension can cause the height-to-depth ratio (aspect ratio H/D) of the rack to increase if shelves are added above the splice point. This addition may cause the H/D ratio to exceed 6-1 ratio. When this ratio is exceeded extra measures for stability are required by the RMI Specification.
Adding frame extensions so additional shelves can be added that causes the total bay load to increase can obviously be a problem if the strength of the existing frame is not great enough to handle the added load. In elevated seismic risk locations, raising the center of gravity of the loading on the frames by adding load and bay height may cause the anchorage to be overloaded during a seismic event.
In summary, anytime the pallet rack bay configuration is changed or load is increased the rack should be re-evaluated by a qualified engineer.
Exception: If frame extensions are added only for product fall protection or to support product fall protection netting and the load beam elevations are not changed a design review may not be needed.