As a construction worker, there is a good chance you will be on a large job site with a crane at one time or another. This piece of heavy equipment is often rented in times of need, because most construction businesses don't have a place to store a gigantic crane when not in use. Many construction companies also do not regularly employ specialty crane operators when they don't have a crane on the job site, because of their high salaries.
You and the other workers may not know a lot about cranes because they are not a regular fixture on the job site. Because of this lack of crane expertise on your team, it is a good idea for you to learn how to read a crane load chart so you can be as safe as possible. This is especially important if you are loading items onto the crane hoist, or working within close proximity to the crane.
In a nutshell, every crane has a load chart that specifies its capabilities. The chart will tell you about the crane's features and lift capacities for various distances and angles. It is imperative that you review a crane's lift chart before you rent a crane so you can ensure that particular crane can handle the job. If the crane is overloaded, it becomes a major safety hazard. Keep reading to learn what you need to understand in order to read a crane load chart.
1. Lift Capacity
You will see a legend at the top of the load chart. This tells you what the crane ratings are when using different counterweights and with the outriggers extended to different lengths. This chart helps you graph out the specific lift you'll need for the crane in order to accomplish the task at hand. On the left axis is a "ft." indicator, which represents the distance from the center pin to the center of the load being carried by the crane. This is also called the "radius."
2. Weight & Dimensions
Often the most prevalent section of a load chart is the area that provides weight and dimension information. You can find steering dimensions, transport weight limits, and data for operating the crane with the outriggers extended. This information is very important if you are going to operate the crane in a confined space. You will also find information on the type of trailer is needed to transport the crane, if it's not on wheels. This section will list any permits, if needed, to get the crane to the job site.
When reading the weight and dimensions, it will be on a chart, with the gross vehicle weight on the top axis. You will also see 2 columns that will tell you the maximum weight load for each axle, which is dependent upon whether there are additional accessories loaded onto the crane or not.
Be advised that the maximum capacity listed on a lift chart is always measured by the shortest lift, which is typically over the rear end of the crane, and with fully-extended outriggers.
3. Lift Angle
This area of a crane load chart lets you know what the maximum lift is if a fixed or luffing jib is used. The higher the lift is, the lesser the load capacity will be. Luffing jibs can be adjusted from within the operators cab. Fixed jibs have a fixed angle that cannot be adjusted.
4. Lift Range
The range diagram is found on most crane load charts and tells you how much boom length is needed to pick up and raise a load at various distances and heights.
5. Crane In Motion
Finally, the crane in motion illustration shows you the various lift capacities for different weights when picking and carrying loads. You can also see how much weight the crane can handle wile slowly moving. This is important if you need the crane to travel in order to move heavy loads from one location to another.
As you review the crane load chart you will know how much weight that particular crane can safely hoist. Make sure you read the entire chart before you work around a crane, and ask resources like Winslow Crane Service Co.