This week we are going to be taking a look at some topics related to heavy lifting operations. This kind of knowledge and skill will be beneficial in several disciplines of rescue, including structural collapse, trench, and vehicle rescue.
Let’s start out by reviewing how to determine the weight of an object in the field. The FEMA US&R Field Operations Guide gives us some guidance with quick weight estimating that we can use on the street. You will want to turn to page 1-31 in the September 2017 FOG (Edition 8.2). The FOG can be downloaded for free from DisasterEngineer.org.
Our make believe scenario is this: The rigging carrying this reinforced concrete pipe has failed and there is a worker who’s legs are pinned under it. We have to perform a lifting evolution in order to free the pinned worker. How do we determine the concrete pipe’s weight?
Use your imagination to slice the concrete pipe long ways so that it is unrolled and lying flat on the ground in your mind.
Measure the dimensions of your new slab and calculate the square footage. You will essentially be measuring its length and width (or circumference since it is actually a pipe).
8′ x 8′ = 64 square feet
Multiply the square footage by the Quick Weight Estimating value in the FEMA US&R Field Guide. For this scenario, we’ll say the concrete is 6″ in depth.
64 square feet x 75 psf = 4,800 lbs.
Round that up to an even 5,000 lbs. to plan the rest of your operation. Now that we know roughly how much our object weighs, we can begin to setup our stabilization and lifting operations with the correct equipment.
Owner / Lead Instructor
Elder Technical Rescue Services, LLC