Warehouse Design: How to Calculate Pallet Racking Needs

How to Calculate Pallet Racking

How do I Know How Much Pallet Racking I Need?

One popular way to design a pallet rack storage layout is to start with a given distance of racking, often referred to as a “run.” The distance of a run represents available floor space on which a continuous stretch of pallet racking will be installed. A run may consist of a couple of bays of racking along the storage wall, or a several-hundred-foot-long stretch in a large fulfillment center. Many medium-to-large applications have several runs of pallet rack storage. But knowing the length of a run doesn’t mean you’re ready to order pallet racking yet.

A typical selective pallet rack system is made of two fundamental pieces — upright frames and horizontal cross beams (and often wire decks, which we’ll get to later) — and those two pieces come in many sizes. This means there’s still some math to be done once you know the length of your run. Pallet rack beams are usually carried in stock in standard lengths, such as 6’, 8’, 9’, 10’, and 12’, although the company you’re buying from may have other odd sizes to choose from. In fact, we often have used pallet rack or closeout specials available in non-standard sizes.

How to Measure for Pallet Rack Beam Length

The length of your beams will depend, in large part, on what you plan on storing. For simplicity’s sake, in our example, we’ll be storing two standard 48” deep x 42” wide pallets per beam level. Our two 42” wide pallets will require a 96” long beam level on which to sit. Let’s also assume we have a 100’ run of space to work with.

How to Calculate Pallet Racking

Remember when calculating the number of beams that there are two beams per beam level.

Pallet Racking Calculator – How to Calculate Pallet Racking Needs

Now we have two of the key variables needed to start our calculations. If we have 100’ of space to work within segments of 8’, that means we need to divide 100 by 8. Since we can’t have half of a bay, we’ll round it down to 12. 12 bays @ 8’ wide = 96’.

That’s pretty close to our goal of 100’, but we’re not quite done. We also need to factor in the width of the upright frame columns. We’ll need 13 frames for those 12 bays. In most cases, that will be 3”, so we’ll need to multiply 3 (inches) x 13 (frames), to get a total of 39”, or 3’ 3”. We’re now at 99’ 3” of racking. If you need a span of racking that’s exactly 100’ long, 99’ won’t cut it. However, if your application is like most and you just need to stay within 100’, 99’ 3” is pretty good.

To figure out exactly how many beams and wire decks we’re going to need, we’ll simply take the number of beam levels per bay, multiply that number by two, and then multiply the answer by the number of bays. Assuming we have two beam levels per bay, our math will look like this:
2 (beam levels per bay) x 2 (beams per level) x 12 (total bays) = 48 beams.

Calculating the Number of Wire Decks Needed

Finally, we calculate the number of wire decks needed. In our case, this is an easy problem to solve. For 96” beam levels, two 46” wide wire decks are needed per level. That means the number of wire decks we need will match the number of beams. In some scenarios, such as 12’ beams, three wire decks are needed per beam level. This just means we’ll take the number of beams and multiply it by 1.5 to get the number of wire decks needed.

And just like that, with a few simple math problems, we’ve calculated the number of frames, beams, and wire decks we need for our run. While it may seem easy enough (and often times is), we usually recommend consulting a material handling professional before settling on a final number of components to order. They may be able to provide ideas for an even more efficient warehouse layout design, offer handy information, or just double-check your calculations for you.

For the visual learners, Systems Design Specialist Brian Koski gives us an example of how to apply the math covered here.