Rigging and lifting hooks for cranes, hoists, and slings are an essential part of almost any rigging application. Choosing the correct rigging hook for your lifting application is just as important as choosing the correct sling or hoist. Lifting hooks come in a huge variety of designs, materials, and sizes, all suited for different lifting applications. — Tri-State Rigging Equipment
In addition to choosing the correct hook for your lifting application, proper maintenance and care of the hook are of the utmost importance!
Saturday” comes paraphrased by Craneology from the ASME B30.10. More specifically, we’ll be discussing the list of damaged items and discrepancies mentioned under the Removal Criteria section.
According to the Removal Criteria section, there are 13 items that can take a crane hook out of service.
These items include but are not limited to:
Missing or illegible identification
Thread wear, etc.
We’ll be focusing on 3 items mentioned in the volume, in this blog. Wear, Deformation, and Throat Opening.
ASME says that under the conditions described below, a hook must be REMOVED from service:
… there is evidence of any wear exceeding 10% of the original dimension…
…any bend or twist from the plane of the unbent hook (more than 0 Degrees)…
… increase in throat opening of 5% (not to exceed 1/4”)
Item 1:Wear. Most times when people consider wear in the hook, they’re only inspecting the bowl/saddle of the hook, overlooking where the standard states you must inspect using original dimension(s), meaning all dimensions of wear on all parts of the hook. The only way to find the original dimensions of the hook is from the manufacturer, and they should provide this information to the customer as it is mandatory.
Wear can happen in different places on the hook, considering different operating environments and stresses imposed on the hook. Additionally, operating practices applied to the hook (whether proper or not), can greatly affect the severity of the wear.
Item 2:Deformation. More specifically, a twist in the hook “from the plane of the unbent hook”. In common terms, this simply refers to the tip of the hook in alignment to the back of the hook. If they are out of alignment by more than 0 degrees, they must be removed from service.
If you think this requirement is overkill, please consider how you would get a twist in a crane hook to begin with. Typically, that occurs from abusive, reckless crane operations; or from swinging a load that is still not fully suspended. Twists in the hook DO NOT occur under normal operations.
Item 3:Throat Opening. This refers to the hook opening itself. This is the area usually covered by the latch, and so a latch that will not properly close is the first indication that you have an increased throat opening.
ASME’s Removal Criteria requires that: 5%, from the original manufacturer dimensions, not to exceed ¼". This means that if you have an exceptionally large hook, you may reach a ¼" at 1 or 2%. If that’s the case, it must be REMOVED from service before reaching the full 5%.
Something to consider is the mousing of a hook as a temporary alternative measure, in the event of a broken hook latch.
The purpose of mousing is to act as a latch for the sole purpose of retaining loose attachments under slack conditions. Mousing is not intended to prevent the increase of the throat opening or bear any weight for that matter.
Remember, SLACK conditions only.
Mousing a hook can cover up any indications of a throat opening if left on the hook long enough. As a result, you could be using a hook long after you should, if inspections are not conducted regularly.
As Always, BE SAFE.
Craneology, Inc. is a registered “Service Disabled Veteran Owned Small Business” and a minority-owned business, whose main objective is to provide comprehensive training courses and certification examinations. Craneology, Inc. achieves this objective through its team of expert trainers from the various fields within the Crane and Rigging Industry. Craneology, Inc. has provided training and certification services locally, and around the globe. We look forward to working with you!