VNA, or very narrow aisle, is a warehousing method. The VNA design makes the warehouse aisles as narrow as possible while using tall racking systems. This makes material storage extremely space efficient and there are many obvious benefits. However, there are some important things to consider when implementing this method.
How Flat is Your Floor?
Designing a VNA method for your warehouse requires that you take a critical look at your surroundings. You should consider the floor that your racking is going to be placed on. In a VNA design, the pallet racking is placed as close together as possible. The pallet racking will likely be very tall, and floor flatness is critical. The rule is that the taller the pallet racking will be, the flatter the host floor needs to be. If the pallet racking is placed on an uneven floor, leaning will occur. There are certain floor flatness recommendations depending on the height of your highest load beam. Do your research and properly plan for the VNA system you want to implement.
What is the Plumbness of Your Rack?
Your forklift and your pallet rack both need to be plumb for the same reason. When your pallet racking is being installed, make sure the installers place a level on each upright. The plumbness should be within 1 inch at 30 feet. Your installers should be using rack shims under the rack footplates. This will help to make sure that the pallet racking is plumb.
What is Your Floor Loading Capacity?
Your warehouse floor should be a minimum of 3,000 psi concrete. The reinforcing material, or rebar, should be a minimum of 3 to 4 inches below the surface of the concrete and distributed evenly. Oftentimes, more modern floors are being mixed with ferrous hardening agents instead of rebar. In these cases, the contractors need to make sure that the ferrous hardening agents are being distributed evenly throughout the entire warehouse floor. Otherwise, the forklift can lose the wire guidance signal unexpectedly because the signal from the wire guidance wire may be diffused.
Do You Have Crack Control?
Changing the rack design on an existing floor requires that you also be aware of the condition of that floor. Check for any cracks. How large are they? If the cracks are larger than 3/8 of an inch at the surface, you should repair them with an epoxy grout that is equal to or even harder than the surrounding concrete. You should also check for any spots on the floor that have the top surface starting to spall (disintegrate) because they can be dangerous when in the path of forklifts. They should be repaired immediately. Without repair, the forklift will make these areas much worse.
Be mindful of all of the above when implementing a VNA design in your warehouse. The team at PFlow can help with any questions you may have about your warehouse design, especially if you’re considering using a vertical lift.