Lifting Lug testing requirements... or best practices.

[whatinspector]

Just going through some of your forums and finding some great advice.
What I cannot find however is any requirements for any Visual or NDE inspection post installation.
Is there any mention of VT/NDE requirements for lifting lugs?

 

[dhengr]

Whatinspector:
Every detail in the universe is not YET codified, but they are working on it, and you’ll need and 18-wheeler to carry your code books around. Your typical shop QC stds. or structural notes on drwgs. should cover this, you just don’t cover/test every load carrying weld done each day. At the same time I don’t want my newest/learning welder doing these welds either. There are at least two levels of lifting lugs, and they each deserve their own FoS, testing/inspection, etc: (1) lifting eyes or lugs which lift a piece of equip., place it, and replace it in 25 years should have a FoS of 1.5 to 3 and inspection or a confidence level like any other weld; (2) lifting eyes or lugs on equip. which is used hundreds of times, in different locations, by different crews, etc. should have a FoS of 4 or 5 and higher degree of inspection and testing, and further regular inspection during their life, because of their usage, wear and abuse in the lifting and rigging process. In case #1 the lugs are testing during equip. loading for shipment, and in case #2 lifting equip. should be tested to 1.25 or more before they are used for an actual lift.

All of them should have good clean detailing of the parts and the welding details, good clean load paths from the shackles to the lifted equip. There should be no out of plane lug bending which is not fully accounted for in the design, most eyes are not intended to be loaded sideways either, no reentrant corners in the welding, weld terminations should not be highly stressed because of eccentricities, lugs should align with structural webs/walls in the lifted equip., not cross that web, or just be out on a thin cover/top plate. Welds should be balanced, and adequately sized, but they do not often need to be full pen. welds. Welds should be free of undercuts, craters at terminations, have a good appearance, be a normal structural weld quality. Welding around corners and sharp edges should be avoided because they often leave notches and other nasty stress raisers. All plate edges should be clean and smooth and corners should be rounded/beveled to minimize nicking in use, this includes the pin hole. It is often wise to match the pin hole dia., location and the lug thk., (by adding doubler doughnuts) to the shackle to be used, so that a smaller shackle and pin can’t be used. Mag. particle and penitent testing are fairly common, other testing methods are often pretty difficult to use and get meaningful results in many cases. Of course, the customer can spec. various inspections and methods, but often needs some advising as to the effectiveness of some methods.

Take a look at ASME BTH-1, “Design of Below-the-Hook Lifting Devices,” for their take on lifting lugs, it’s basically the Std. in the US. Various good/advanced Strength of Materials, Theory of Elasticity, Welding and Fatigue textbooks cover some of the critical details found on lifting lugs, and are worth studying.