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How To Calculate Load Before Renting a Crane

How To Calculate Load Before Renting a Crane

Cranes have been around since as far back as the time when humanity was mainly Mesopotamia. The technology was used in Ancient Greece for construction projects. They have come a long way in the past several millennia. It is not uncommon for cranes to become semi-permanent fixtures in the skylines of growing cities like Charlotte. 

There are hundreds of jobs that benefit from the lifting power of cranes. Depending on your project or site, you might use tower cranes, mobile cranes, level-luffing cranes, or overhead lift cranes

When it comes to jobs that require cranes, one of the questions your crane rental company will ask is the total weight of the load. There are several things you need to know about calculating the weight of a load before you rent a crane. 


What Is Load Calculation for Cranes?

Load calculation refers to the way in which you determine how much weight the crane will be lifting. While it can be relatively straightforward, at times you will need to do some math and work with formulas in order to find the number your crane rental company will need.

1) You Must Include the Weight of Everything Being Lifted

Your crane will be lifting more than just the object you need to have relocated. It will also be lifting everything required to hoist the load as well. That means your load calculation must include:

  • All lifting gear
  • Hooks and rigging
  • Ropes and harnesses 
  • Beams and chains
  • Anything being picked up by the crane 

2) Start With the Easy Methods

Before you attempt to manually calculate the weight of your load, there are a handful of methods that may make finding that number easier:

  • Check to see if the weight of the lord is marked. It may be somewhere on the object itself or listed on the packaging. 
  • You may be familiar with the weight of the object you are moving or have the information you need written down in your records. 
  • If you have them, the design plans or engineering paperwork may include the weight. 
  • You might find the weight of the load on the bill of sale receipt or the shipping label. 

3) Use an Industrial Scale

Depending on the size, shape, and weight of your load, you may be able to weigh it using industrial scales. You can typically find industrial scales in shipping and receiving departments.

4) Check Manufacturer Specifications 

Check with the manufacturer to find out if they have specifications that will help you determine the weight of the object you’re lifting. If you cannot find the information on the paperwork included with the object, you may be able to find it on their website. Of course, you can also try giving them a call. 

5) Try Using a Dynamometer

These devices can measure the weight of a load by being attached directly to the rigging. It will output the weight to a digital screen for you to read. These devices are typically quite accurate. 

6) Manually Calculate the Weight of the Load

If you have not had success finding the weight of the load in any of the easiest ways, you may have to calculate it manually. Here is how that works:

  • First, you need to determine the volume of the object. For squares and rectangles, the formula is “Volume = Length x Width x Height.” For cylinders, the formula is “Volume = 3.14 x Length x Width x Height.” For some objects, you may need to break them down into multiple rectangles to ultimately get the volume. 
  • Next, you will need to determine the weight of the material your load will hold. You can typically find charts online with the data regarding the weight per cubic foot for everything from Aluminum to Zinc. 
  • Finally, you can determine the weight of an object by multiplying the approximate weight by the volume you previously calculated. 

This can be a challenging process, but it is vital for ensuring you have the best experience with your crane rental. Lifting more than the crane’s capacity will damage the unit and could result in catastrophic failure. This could lead to significant damage to the products you are lifting and injury to your people. 

If you are in need of a crane for your project, Parker’s Crane Service can help. We have been supplying crane rentals to the Carolina piedmont and foothills for 50 years. We are happy to answer your questions and even walk through the load calculating process with you. Contact us for more information about how you can rent your mobile crane today.