Working Load Limit For Flatbed

I'm putting together a new version of the High Road and I think there's a typo in the manual.

The old manual said:

The combined strength of all cargo tiedowns must be strong enough to lift one and one-half times the weight of the piece of cargo tied down.

The newer version states:

Federal regulations require the aggregate working load limit of any securement system used to secure an article or group of articles against movement must be at least one-half times the weight of the article or group of articles.

It says "one-half times the weight."

Shouldn't that read, "One and one-half times the weight" ??

They’re both correct. For securement it’s one half but the first statement started lifting and rigging equipment has different requirements. It’s interesting that the first statement was even in there to begin with because it’s very rare that a roofing company would ever use a drivers equipment to lift and move cargo.

In the actual regulation (§393.108 (d) (Aggregate working load limit for tiedowns) "One-half" is used three times. Doesn't look typo to me.

But I'm not a flatbedder.

They’re both correct. For securement it’s one half but the first statement started lifting and rigging equipment has different requirements. It’s interesting that the first statement was even in there to begin with because it’s very rare that a roofing company would ever use a drivers equipment to lift and move cargo.

Since we're on the topic of flatbed securement Robert B what is your take on the indirect vs direct tie down and the prevailing wisdom that a direct tie down only gets credit of 50% toward the aggregate working load limit.

One half the weight is the correct WLL for a flatbed load.

I don't really understand that first statement which says "one and one half." Lifting requirements are different, but they clearly are not talking about lifting. They refer to "the combined strength of all cargo tiedowns." If there is a typo it is in the old manual.

what is your take on the indirect vs direct tie down and the prevailing wisdom that a direct tie down only gets credit of 50% toward the aggregate working load limit.

I go by their math. I am not sure I understand the engineering behind it. I just know that I have run across a few inspectors who really know their stuff on securement rules. That one is sort of a "gotcha moment" if you aren't aware of how it works. I'm not saying I agree with it, but I do try to remember it when calculating my load securement.

It would seem if you put two chains (one on each side) on the anchor points of a piece of equipment and then came back to the same side of your trailer with each chain, that would be twice as strong as putting one chain through the anchor points and terminating it on the opposite side. The math tells us that those two methods are equal in strength. I am sure there is something about the stress put on the angle of the chain when it goes back to the same side, but it has puzzled me for years. I do it with their math, but I am not sure it is correct.

They’re both correct. For securement it’s one half but the first statement started lifting and rigging equipment has different requirements. It’s interesting that the first statement was even in there to begin with because it’s very rare that a roofing company would ever use a drivers equipment to lift and move cargo.

Since we're on the topic of flatbed securement Robert B what is your take on the indirect vs direct tie down and the prevailing wisdom that a direct tie down only gets credit of 50% toward the aggregate working load limit.

I’m in agreement with OS here although I disagree with the way FMCSA determines their decision. It’s not so much that there’sa reduction in tension on the chain and what it’s covering or attached to but more to the point of where and what forces of motion it’s protecting against. The largest force on the load is going to be forwards motion, followed by side to side and then to the rear. By going all the way across or over the object, you’re providing a restrictive force on the entire object as opposed to sat on something like a transformer with chain points on the sides. Chaining one side is only restricting the one side and if I had to guess, it’s where they come up with half the rating even though in regard to the actual chain and binder that isn’t true but it’s only restricting movement on half of the load. I hope that makes sense. I’ve honestly never had anyone explain why they declare it the way they do but once you’ve secured a bunch of different loads using all styles of securement, you can see how they come up with it.