Crane Rated. The ASME B30.20 and German Standards
The standards we work with in North America have us load testing our crane materials handling equipment. If you look up OSHA, you’ll find 1926.251 has that set at 125%. It’s the same number you’ll find in ASME B30.20. The ASME does lend some added benefit in that they require a design criteria of 300% or 3:1 as the safety factor. So if you are buying a crane rated bin that is rated, that isn’t ASME Certified, it’s likely that it doesn’t have the 3:1 safety factor, or maybe it’s made of a material other than “carbon steel” which is required for ASME. We go beyond all of this. Let’s take a look at the process we use and see how we go beyond all of the standards and most other manufacturers.
I learned long ago that cranes are designed well past the load charts. They aren’t going to fail at 110%. I’ve been in a tower crane at 125%. I’ve heard of 150% structural testing of a mobile crane. Now the overturning limits are another matter and it varies by cranes. I remember old crawler crane operators saying in unison, it doesn’t have the third track pad up, so we are good. (this is not me advocating for this standard) For us in attachments, we don’t want to have variables. We provide a rating. Of course that’s not 100%. If something goes wrong, we don’t want a failure to be as easy as minor miscalculation. So we start with the requirements. 125% is a common testing scheme in engineering. It matches most governmental requirements. Many regulations around the world like ASME B30.20 require a 3:1 safety factor. If you say it’s rated at 1000 lbs, it must be able to hold 3000 lbs. But they don’t require that test. Just that it was calculated. This is a place where human error could occur. Today’s Finite Element Analysis should catch an error, but what if it misses too? The German’s have planned for error. They simply test to 300%. Easy peasy. It’s pretty hard to miss anything with this being the end test. If it survives 300%, even manufacturing errors will easily let it survive 100% loading.
Eichinger goes yet another step. We test to 300%, then to failure. Why would you not want to know where the weak link is for the option to improve? Understanding where to inspect closely over the life of the lifter is another advantage. But then we also know our ultimate design factor in the real world. And it’s documented. Just how ridiculous does this look?
Large stack over 300% of the bin rating causing structural failure.
These plates are solid steel. They are milled crane pallet fork tines in this case. This is the level of overload required to cause a failure in our bins. One has to plan for filling the open space almost entirely with solid steel, then double it. A crane rated item properly sized is actually quite difficult to make fail. And this is why going on and on about ensuring a crane rating is important. I know that I’ve seen lifts fail due to lifters failing. In each case, the lifter was not ASME B30.20 certified. In my career nearing 30 years, I’ve heard of one concrete bucket coming off of a hook. I never did hear the reason. I would bet it was rigging or a human error. A month plus ago a crane man basket crashed in Germany. Turns out the crane managed to hook something during the lift while hoisting at full speed and the main hoist rope failed before the crane man basket. Think about that. That basket and the rigging is required to have a 7:1 design factor (single pendant) and the hoist rope for the whole crane failed before that basket meant to lift four people.
The level of safety delivered by crane rated items versus job site built lifters is a stark gulf. We deliver that safety. You don’t want to risk lives, or your company’s well being on poorly built lifters. Even if they weren’t built by us, the safety delivered by items at least built in accordance with ASME B30.20 are the way to get things done. I see items built out of aluminum or other materials and I’m left wondering how they do 5 years on when the sharp and heavy items are landing away at that soft metal. Metal that doesn’t do as well at resisting deformations. Items that aren’t required to have a 3:1 safety factor. Not to mention a 300% test that we deliver with our equipment giving you that comfort in that in most uses it’s not even seeing 20% of it’s ultimate capacity which begins to wear down and stress structures.
1312 with 13230 lbs of steel plates in a 4400 lb bin. Shackles can fit in those structural hooks too for a better D/d Ratio
If you want to ensure safety for your people, our crane rated designs have been overload tested to a level that is simply absurd. If you like the idea of knowing your lifter has been overload tested in the development phase to this level in checking for safety, then we should be your supplier. We are showing you our homework here. AI isn’t designing and testing our equipment. At the end of all of the important engineering, we need real world testing so real world humans can be safe when working with Eichinger attachments.
