- Figuring out the weight of the load that you're lifting
is one of the first things you should do
when you're writing your lifting plan.
And in this video,
I'm gonna teach you how to do just that.
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Welcome back to the Lifting & Rigging Channel.
My name's Devon and today I'm gonna take you
through one of the most important steps
in your lifting plan:
Determining the weight of the load
that you're about to lift.
We'll look at the pieces of gear
that you need to consider into the load weight,
some simple methods of figuring out the weight in advance
without doing any calculations whatsoever,
and then of course we'll wrap up by working through
the calculations and formulas and selfs,
both of simple and complicated shaped loads.
So first, let's dive into what pieces of gear
you need to consider into your plan.
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The total weight of the load must account for every piece
of lifting gear involved in that lift,
and I mean everything:
The hook block, the lifting beams, the shackles,
the lifting slings, and forgetting to factor the other
pieces of rigging rigging hardware means you're starting
your lift with a flawed lifting plan.
So, let's look at a few different methods
of determining the weight of a load.
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First, look to see if the weight
is marked on the load itself.
Sometimes manufacturers place the weight on the load
for shipping purposes,
so the weight may already have been
spelled out and calculated for you.
So if you can find that,
it can guide you to the right rigging equipment
for that pick.
Second, look for engineered prints or design plans.
Product prints and engineered drawings of the load
may indicate the final assembled weight of that load
and it might even help you find a few anchor points
that you didn't even know existed.
You can also review the bill
of lading or shipping documentation.
If the load that you're about to lift
was shipped or transported to your location,
there should be some type of weight information
on that shipping paperwork.
It had to go on that semi-truck, they had to count
for that when they were driving,
so you might already have that covered.
If the load is a product or piece of machinery,
the weight of that load may be indicated
on either the paperwork
that was provided by the manufacturer,
any information on the manufacturer
or distributor's website, or the product specifications
in a catalog or product brochure.
Those are all good reference points to start.
There are a few times when you can add other devices
into your rigging that can provide a read-out
and determination of the load weight
when it's lifted slightly off the ground.
Now, these devices measure and display the weight
of the load in a few different ways,
and some of the more advanced ones,
probably the more expensive ones,
can even send the readout to handheld devices
or remote workstations to help gather
the correct load weight before you make your lift.
And if none of those options work out for you,
then it's time to figure out
how to calculate the weight of a load all by yourself.
So let's look at some calculations and some formulas.
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So a lot of these formulas you probably already
heard of when you were going through school.
These are just refreshers.
So determine the volume of a load
for a rectangle or a square specifically,
volume = length x width x height.
For a hollow cylinder it's a little more complicated.
Volume = 3.14 x length x the wall thickness
x (diameter - wall thickness).
For complex shapes, in some instances,
imagine the entire object is enclosed in a rectangle,
and then calculate the volume of that rectangle.
Or, you can break that object into two or more smaller
rectangles and then calculate the weight of each part
and then add them together.
Step two, determine the weight
of the material you'll be lifting.
You can use a material weight table to figure out
the pounds per cubic foot of the material you'll be lifting.
Step three: Determine the weight of the object.
Multiply the approximate pounds per cubic foot
of the material, times the calculated volume of the load
to get the weight of the object or the load itself.
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All right, so now that you know the steps,
let's calculate the load weight of an aluminum block
that's six feet long, three foot wide, and four feet tall:
You start with step one:
you gotta determine the volume of the load.
Again again, volume is length x width x height.
So six x three x four gives us the volume of 72 cubic feet.
Step two: determine the weight
of the material you'll be lifting.
Using this table we see that aluminum
weighs 165 pounds per cubic foot.
Step three, determine the weight of the object.
Multiply the volume of the load, 72 cubic feet,
by 165 pounds per cubic feet
which gives us the load weight of 11, 880 pounds,
or 5.94 tons.
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This next example is gonna be a little bit more complicated
so we're gonna slow it down a little bit
because there's a lot of different phases
to get through this.
For this example we're gonna look at a steel pipe
that is eight foot long, has a three foot outside diameter,
and a wall thickness of 1.5 inches.
As always, you start with step one:
you determine your volume, and it's a little trickier
since you're using feet and inches in this calculation.
So the formula is volume = 3.14 x length x wall thickness
x (diameter - wall thickness).
So before you can run this calculation,
you've actually got to convert your inches into feet
and then provide it.
And so 1.5 inches is equal to 0.125 feet.
And now that you have those all converted,
now you can actually calculate your volume.
So 3.14 x 8 feet x 0.125 feet
x (3 feet - the converted 0.125 feet)
reforms your calculation as 3.14 x 8 feet
x 0.125 feet x (2.875 feet) and that gives you
a volume of 9.03 cubic feet.
And again, that's more complicated but it's important
that you understand the steps and you take you time
as you go through them.
Step two: use the table again to find the pounds
per square foot of steel, which, using our table,
is 480 pounds per cubic foot.
Now you can perform your calculation.
9.03 cubic feet x 480 pounds per cubic foot
gives you the load weight of 4,334 pounds or 2.17 tons.
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For complex shapes the goal is to simply
take a complicated shape and make it simpler
by breaking it into smaller, more understandable pieces.
And so for us, this example, we're gonna look
at how to calculate the load weight of an irregular
shaped concrete block.
First, the goal is to break down and separate
the two objects into normal rectangles and then to calculate
each section individually, then combine them.
And so what we've done is we've broken them into a top part,
which is three feet x two feet x four feet
and a bottom part, three feet x two feet x nine feet.
And then your steps are the same.
Step one, determine the volumes.
The volume of the top is four feet x two feet x three feet
which gives you 24 cubic feet.
The volume of the bottom is nine feet x two feet
x three feet, giving us 54 cubic feet.
The total volume is volume one plus volume two
equals the total.
24 cubic feet plus 54 cubic feet equals 74 cubic feet.
After doing that, then you can move onto step two.
Determining the weight of the object itself.
Using the table again to find the pounds per cubic foot
of concrete, which, using our table,
is 150 pounds per cubic foot
we can continue our calculation.
So take take your 78 cubic feet x 150 pounds per cubic foot
and your complex concrete shape is approximately
11,7000 pounds, or 5.85 tons.
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Like anything, learning to apply these formulas
will take time and practice.
And so to assist you, we put together
this Load Calculations Pocket Guide.
Save it to your phone, save it to your computer,
use it for references anytime you need it.
You can also grab our lifting
and rigging best practices infographic.
This is another tool you can use to ensure everything
from operator training to environmental conditions
have all been factored into your lift plan beforehand.
I hope this video was able to help give you
a better understanding in how to calculate the weight
of a load before your next overhead lift.
Math is not magic.
It's just understanding the steps and the calculations
that you need to apply.
Now if you're working through this on your own
and you're not really getting it down
and you need some help, don't hesitate to reach out
to one of our lifting specialists.
They'd be happy to help you, to walk you through it,
to help you give you an even better understanding
of these lift plans.
Now, if you like this video and if it was helpful to you,
please like it, share it with your coworkers,
and maybe even subscribe to the YouTube channel
so you don't miss out on any future videos that we make.
From all of us here at Mazzella Companies
and for the Lifting & Rigging Channel,
my name's Devon, thank you for watching.
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