One question we have received numerous times is:

why can’t we just use the LMI or LID on the crane for our lift plan? 

The LMI and LID are useful devices on the crane, but the short answer is a big fat NO. 

The LID is a load indicating device and it indicates the load on the main lifting line.  This indicated load, when appropriately modified for parts of line and friction effects, indicates the weight of the lift.  If this value exceeds the allowable lift, the device will provide a warning and may also stop operation.  The LMI is a load moment indicator and it is a device which senses both the load and the boom angle, and by correlating the boom angle with the allowable lift at that angle provides a warning and may stop operation.

These devices are necessary on a crane, but they should not be the only option when planning your lift.  First it is only in use when the lift has already started so planning has already been thrown out the window.  Secondly, there are other items to the lift plan that the LMI will not help out on including wind speed, ground bearing pressures, proper rigging, etc.  The LID can be used as a tool to make sure the lifted weight matches the paperwork prior to lifting the load more than an inch or so off of the ground.

These devices can be effective when the crane is on solid ground and has its outriggers placed properly with the crane leveled out.  If the crane is not set up properly, then these devices may not function properly.  Part of planning is making sure the crane is setup in the correct location and per manufacturer’s recommendations.  These devices are also set up for a particular crane configuration.  If a jib is added to the tip, then the LMI or LID may not detect this additional deduction. 

It is necessary to plan out every lift.  Even the most standard lift needs a simple lift plan to make sure that the lift is within the limits of the equipment and is accomplished safely. 

We want to make sure you have a successful lift and that starts with proper planning.  We can help in this process by helping to create a lift plan with you whether it is a standard lift, non-standard lift, or an engineered (critical) lift.  Here at The Dothea Group, we will do our best to meet your schedule needs and we will provide efficient, engineered solutions to better your project, improve safety, and increase your bottom line. 

If you are interested in learning more about our engineering services, contact us today.  We can partner with you to ensure a successful bid or project.