If you're opening up a small business with its own small warehouse, be aware of a very simple and effective safety move if you are storing items on pallets and pallet racks. Items that you are not ready to unload, send off, or do anything else with should stay in neat piles on pallets, with the whole thing shrink-wrapped to form one package. This is a common requirement in quake zones. However, it's a very good step to take even if you don't live in a quake zone and you're planning to have only short racks. Remember that quakes aren't the only danger that a warehouse could face.
Keeping It Together
When items are stored on pallets and all shrink-wrapped together, all of them plus the pallet become one unit. This unit does not move all that easily in the event of a quake. In warehouses where items are stored on tall racks that tower over people, the shrink-wrapped pallets prevent items from falling from the shelves. The traction provided by the shelf for the bottom of the pallet also helps keep the whole package on the shelf.
Even if your warehouse will be in an area not known for quakes, shrink-wrapping items on pallets is still the way to go. Your warehouse could be in a fracking zone, for example, and experience sudden quakes from the wastewater storage. Your warehouse could be hit by a truck; as far-fetched as you might think that sounds, it can happen, and you don't want to deal with lots of items falling from shelves.
Another problem is that, if you don't inspect pallet racks and keep them in good shape, they can fail and collapse. If this happens, keeping items on shelves all shrink-wrapped together reduces the mess that you have to deal with.
If you do encounter shaking, either from an unexpected quake or from something else, inspect the pallet racks. Use straight edges to check that racks are level, both horizontally and vertically. Check all connections for bolts that might have popped out of place. If you find any questionable racks, remove the items from the shelves. If they're all shrink-wrapped on pallets, removal will be very easy with a forklift.
If you have other questions about pallet rack safety, talk to pallet companies as soon as you can. It is easier to modify plans for your warehouse now when you're first starting out, than it is to change everything around once you have all of your inventory in there.