I know I'm in deep at work. We took a trip to Home Depot for a doorknob, some fertilizer, some charcoal and a few other household goods, and I couldn't quit looking at the .
Essentially, the is about moving stuff and storing stuff. And the Home Depots and Lowes and BJ's of the world basically take of stuff from trucks or trains or boats and move them to warehouses where they sit on .
Somewhere in the back of your mind, you knew this, you likely just never thought through the process. There's actual thought that goes into those shelving units, and I'm not talking about from a marketing and store layout perspective. What goes on the shelves is important to consider, and so is how it gets there.
I've never noticed grooved tracks on the floor, so they're not using something like an . They're likely, instead, either using some sort of , or possibly a small , since when it comes down to it, those aisles aren't all that wide.
From a technical standpoint, the shelving is only the metal grating on which you actually put the stuff. The unit on which you lay shelving is called racking. Racks have certain standard widths because – the wood or plastic things that a giant bundle of paper towels, for instance, comes stacked on – have standard widths.
(Aside: There's a lobbying fight in Congress right now. Some plastic pallet manufacturers want stricter fire code measures for wood pallets, which would essentially make wood pallets much more expensive both to manufacture and to use. I hate when competition gets worked out through legislation. If you have the better product, people will use it.)
Racking is set up in various ways depending on how you load it. If you go to buy bulk nails or screws or whatever, the shelves are just set up to hold bins, and someone puts those on by hand. The boxes of 50 granola bars you get from BJs were once on some sort of pallet and were probably wheeled out of the warehouse on a dolly to be unwrapped and manually placed on lower shelves. But if you look up, you'll oftentimes see bulk items still wrapped in giant loads. Sometimes they're even still on pallets.
Then there's those long pieces of wood or piping you can get – the kind that doesn't fit on normal racks because the support beams would get in the way. So they're on what's called shelving. Essentially, it's a beam supported from only one side. People have these things in their homes, too – you might screw or nail a piece of prettily designed metal into your wall and place a piece of painted wood on top for a nice shelf. Those pieces of metal are cantilevered; they're supported from the back by the wall, but they're on their own for the rest of it.
There's a whole process to choosing whether you're going to just slide the pallets in and use the pallets themselves as the shelving, or whether you're going to place the load, with or without the pallet, on a bunch of rollers to do the sliding for you, or something else.
There's also the whole thought of how you're going to unload. Most stores use a method, just like if you were loading your car with groceries – since the first thing you put in the trunk is against the back wall, you grab the last thing you put in first. Since warehouse stores tend to put their racks up against the wall, or back-to-back with another rack that has different items on it, this system works best.
Some warehouses, though, use a system, where you load something from one side, and unload it from the other. If you're loading and unloading something like this with a , you use a , which a truck can enter from either side (or drive all the way through if there's not a stack of something in the way). Those store racks would be , which a truck can enter, but then has to back out because there's support beam or something in the way.