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Tuesday, June 15, 2010

Putting pounds on pallets

This blog is about using elementary math to solve everyday problems. This week I'm fascinated with pallets in our warehouse. Today we look at weight issues, because books are HEAVY!


There are specs for wood pallets. Have a look at Pallet Central if you are intrigued.

Now here's a bit of math:
  • A single wood pallet can hold about 5000 lbs. if set by itself on a concrete floor. 
  • If wood pallets are stacked 2 to 4 pallets high, the limit is 1938 lbs per pallet. 
  • When loaded length-wise onto a pallet rack (big shelf) the limit is 2085 lbs
  • When loaded width-wise on a pallet rack, the limit is 1728 lbs.
Q1. Assume we have pallets that weigh 50 lbs. We will stack them 3 high. We will load them to the nearest 100 lbs below the rated limit. What will be the ratio of load to pallet?

A1. Maximum load for stacked pallets is 1938 lbs, so if we load to the nearest 100 that's 1900 lbs. 
Let's include the weight of the pallet in that overall total, so the pallet is 50 lbs and load 1850 lbs. 
Fifty pounds goes into eighteen hundred fifty pounds exactly thirty-seven times.
The load to pallet ratio is 37:1

I assumed the springs on a truck were the limiting factor how much weight it can carry. Mike, our truck driver, tells me it's also critical to check the rating for the floor of the truck box or trailer. His truck has a reinforced floor so he can drive the forklift in there. A typical trailer can handle the weight of the load and a pallet jack, but NOT a forklift. The heavy forklift can crash through the floor!


I checked two of our forklifts. Each weighs 6180 lbs and has a lifting capacity of about 3000 lbs. That's not counting the propane fuel tank (70 lbs), the driver (200 lbs) and optional equipment.

Q2. What is the total weight on the truck when Mike loading 2500 lbs of books with the forklift?

A2. 6180 lbs (forklift) + 50 (pallet) + 2500 (books) + 70 (fuel) + 200 (Mike) = 9000 lbs!