- So if you walk on any job site in this entire country,
and you see anything up in the air,
chances are, it's slings that hold them there.
But what is the working load limit?
What does it take to break them?
In this episode of The Rigging Professor, we find out.
(heavy rock music)
What's up guys?
Devon here from Mazzella Companies,
and today, we're gonna break a synthetic round sling.
We think it's important because you need to know
exactly what the working load limit is
of your synthetic round slings,
and what happens if you overload them.
And to test this, I brought in some help.
Thad is a buddy of mine here at the Cleveland office
and I set him on the floor here at Cleveland HQ
to work with a guy named Jason.
Now Jason is our proof tester.
His job is to make sure that slings, chains, whatever,
get tested so they can do exactly what they're rated to do,
and then he maxes 'em out to see when they break,
and if they broke where they should have.
So I'm gonna pass it to Thad
and he's gonna start by telling you the different tests
that synthetic round sling go through
before you're ready to buy.
(upbeat, bouncy music)
- [Thad] I found Jason inside
and he told me there were two tests
to make sure my synthetic round sling
was safe for the field.
- Well the process before it goes out on the field
is called a proof test.
What we do in a proof test is
we take the vertical working load
which is on this particular sling is five to one,
so the working load of this is 5300, and we take that,
we pull it up to two times the working load,
which would be double that number,
hold it for about 10 seconds and then bring it back down.
- [Thad] The machine we'll use to test the sling
has a carriage for pulling and a carriage for holding.
A pin is dropped down to hold the sling in place
on the pull side and on the hold side.
Make sure the sling isn't tangled, close the gate,
and we're ready to test.
The pulling carriage slowly puts pressure on the sling,
in our case 10600 pounds of it,
and for the proof test, hold steady at that number,
'til Jason ends the test.
We inspect the sling for any damage, like tears or holes
and if it's clean, it passes.
- We took it the the vertical load two times
which was 5300 times two,
and what that does is just makes sure
that it's working properly
and that it was made right. - Okay.
- And the customer normally only goes by these numbers
just to keep them safe.
- So this is safe to use now in the field?
- Yep this is perfectly safe to go to the customer.
- During the proof test,
if something were to happen that it wasn't safe,
what would happen?
- All right well, if it wasn't safe, then it would fail.
And then after that we would go to our inspector,
Brian Gerro would look over it and find out why it failed.
- So the next test we wanna do is a break test.
So how does that work?
- Okay well break test is when we take this
all the way to maximum breaking strength,
which is the five to one ratio,
and for this particular sling I believe it is 26,500 pounds.
- Okay.
- So 26,500 pounds, this should go boom.
- [Thad] The break test is set up
the same way as the proof test.
But instead of holding at a certain point,
the pull carriage keeps on pullin' until the sling fails.
(machine humming)
(loud banging)
- [Jason] There is goes.
- All right so where did this thing break?
- Okay this thing broke at 33100,
so it it broke at about 10000 pounds
over the manufacture breaking strength, so that's excellent.
- Yeah. - Excellent.
So what we do next is remove the pins,
take it out and look at the damage we got.
This one pretty much broke underneath the sleeve.
As you can see here,
these are all the fibers that gives us all the strength.
These fibers would normally be nice and smooth.
They're all bunched up 'cause they popped.
- [Thad] Right.
- If it broke below the broking point,
we probably would pull out a few more,
and break those to see where those break
to get an average breaking strength.
- Okay yeah, that makes sense.
- That's it for today's episode.
And I do hope that we were able to better help you
understand the processes that a round sling goes through
before it's able to be sold to you.
If you like this video,
consider checking out the rest of our Cranes 101 series
or The Rigging Professor as well.
There's a ton of content there.
We're gonna make a whole bunch more.
And if subscribe to our channel
you won't miss out on any of it.
If you have any questions
or if you need help on your next lifting project,
don't hesitate to reach out
to one of our lifting specialists.
They'd be happy to help you however they can.
Thank you for watching.
(bouncy organ music)