Looking for an ISO standard for fixed lifting eyes 1

[kingnero]

I am looking for an EN or ISO standard that describes the design, safety factors, ... of fixed load-lifting attachments.
The problems I'm encountering is defending my design against a client that double checks every aspect of the design and fabrication.

We're talking specifically welded (sometimes bolted) lifting eyes on structures that serve solely for the transportation and installation of the parts: fixed pump skids, large beams, stationary equipment like machine bases.

I am aware of the below the hook standard, but the client does not accept american standards (in order to avoid cherry-picking). Fabrication and NDT are done using ISO standards.
There are also standards for non-fixed load lifting attachments (plate clamps, magnets, vacuum lifters, ...) and spreader beams. I assume however that for single-use lifting eyes, the safety factors are smaller but before committing to a lower FoS I need to have something in written, preferably a standard or an authorative design guide.

Does such a document exist, and if yes, could someone please point me towards it?

Thanks in advance,

 

[robyengIT]

as stated in the attached doc (Norway oil & gas industry - page 50-51 of PDF doc), ref for lifting lug should be FEM standard (the same for fork lift)

 

[dhengr]

Kingnero:
There is no doubt that a client like that is a real pain in the butt. But, at some point in time you should quit worrying about defending your design and tell him how it is going to be. After all, you are the one who is signing off on the design, not him. And, you don’t want it to fail either. There just may not be a specific code paragraph, formula, and FoS for every possible detail in the universe, in every country’s design code in the whole world. Sometimes, you are left with finding several reputable stds., like ASME BTH-1 for one example, and then using your engineering experience and judgement, and running with that. Again, you don’t want it to fail either. Design the 3 or 4 pick points on the machine/equipment, that is, the lifting eyes or pin pls. etc. so that only two of them carry the load, and the other one or two slings are just kinda leveling (non-tipping, non-rolling) helpers. Study the structure for good clean load paths sufficient to really take the potential loads, knowing that you may not know the C.G. to +/- 1mm. Allow for some loading perpendicular to the plane of the pin pl. or eye, some out of plane bending, use good clean fab. and welding details, so they are not stress raisers in themselves, and you probably have it pretty well covered, even without the specific code para. Have the other guy tell you what code or std. he wants you to follow; or what does the spec. and p.o. say on the matter? If they are in your favor…, end of discussion.

Hell, every day, you see volumes of calcs., not all done correctly, or with the right assumptions and interpretations of intent, all to cause a snow-job when the buyer looks at them. Then you see this great big pin pl. with crappy detailing, finishing and welding (with defects), all welded onto a 5/16” cover pl. over the heavy piece of equip., with no load path to real structure, and everyone thinks its o.k. because there where hundreds a pages of computer printout and hand calcs. which no one can decipher.

 

[robyengIT]

a reference can be found in EC3 that is "EN 1993-1-8 Design of joints - connection made with pin".
If it can help (in Italian, sorry) attached you can find a calculation example according to EC3 and according to Italian Standard for steel construction (building
PS : ... any way I agree with dhengr

 

[Settingsun]

You should understand the issue before becoming abrasive with the client. There could be valid reasons, eg their insurer might reject claims if not designed to prevailing standards. And the engineer's insurance might be inadequate or also reject.

 

[kingnero]

Thanks for all the replies. They are helpful, and give me another point of view on this.
I fully understand the reasoning of my client, there is also in no way any discussion about this.
We both would prefer however smaller welds, hence I'm looking for something that specifically addresses single-use lifting eyes.
We both agree that we can only use smaller FoS if we have something in written, in case something goes wrong.

The logic behind using a smaller FoS is:
- no fatigue,
- no chance of using the lifting eye for a heavier load, because it is welded to a specific component
- "no" operator error - transportation/ionstallation of these devices is done by trained operators and following a decent lifting plan. Note the brackets, they're there for a reason.
- no heavy welding, meaning a smaller HAZ (this is important for me)
- no heavy welding, costs less €€€ (this is important for the client)

 

[kingnero]

This is still an issue, we're still using oversized welds(FoS = 4), where all parties agree a smaller FoS would be beneficial. However, before going smaller, we'd like some sort of reference. Doesn't anyone know of a reference regarding fixed lifting eyes?

Thanks again to all who already have replied, your guidance has been helpful.

 

[LittleInch]

Biggest unknown here I think is your item

" "no" operator error - transportation/installation of these devices is done by trained operators and following a decent lifting plan. Note the brackets, they're there for a reason."

There is no way on earth (IMHO) that you can guarantee that or indeed any other form of no shock loading during a lift.

Also no way to guarantee a one use operation unless you go and personally flame cut the things off.

You seem to be chasing a dream and wasting valuable time and resources doing so. FoS on lifting gear is there for a good reason - stop trying to somehow find a way to avoid this and do it properly or not at all.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[kingnero]

You seem to be chasing a dream and wasting valuable time and resources doing so. FoS on lifting gear is there for a good reason - stop trying to somehow find a way to avoid this and do it properly or not at all.

I don't really appreciate the underlying allegation of "not doing it properly", nor is the remarks regarding wasting valuable time correct.
I'm doing it properly, and right now much more time is wasted overwelding the parts.

Dynamic load factors for lifting and handling are 1.2 or 1.4 (whether bridge crane or mobile crane is used), FoS for live load of lifting equipment starts at 2, with boundary conditions similar to what we're doing. All things considered, I can get away with a global FoS of 2.07 if it were non-fixed (i.e. bolted eyebolts) load lifting attachments for up to 16k load cycles, if more than that you have to consider fatigue as well.
There is no logic doubling the 2.07 value for a one-time use just because it's fixed (welded), but I'm eager to hear your "good reason" for this.

 

[kingnero]

An update for those who are interested:

TR 15728 describes the lifting of precast concrete elements.
This standard elaborates in detail on a number of lifting devices, from cast-in female threaded adaptors to connections similar to welding lugs.
My parts aren't precast concrete but rather steel, but the general principles are fully applicable so the controlling third party has approved design according to this document.

Specifically:
The load factor is 1.35, and the dynamic factor are as follows:

Together with the partial factors for the base materials and connection design we are now able to reduce the fillet welds from 10 to 6 layers (and still have redundancy!) which gains a lot in terms of productivity. Thanks for all the constructive input