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Does design of lifting lug have some standard practice?
2

Does design of lifting lug have some standard practice?

Does design of lifting lug have some standard practice?

(OP)
I have a vertical vessel of 5000mm ID , whose top end is elliptical head and bottom head is conical, with cylindrical shell attached in between. The weight of the vessel is 18tonnes. What will be the maximum thickness of the lifting lug ?

RE: Does design of lifting lug have some standard practice?

Suggest you take a look at the R002 Norsok Lifting Equipment document as guidance/reference.

RE: Does design of lifting lug have some standard practice?

In my opinion there is no single "standard practice" that covers the design of lifting lugs (padeyes) for pressure vessels.

ASME VIII contains no specific set of rules for designing the lug .... ASME does, however place restrictions on the selection of acceptable materials, the welding requirements and the inclusion of the welded lug at the time of vessel hydro.

NORSOK, NASA, several companies and individuals all have developed proven guidelines for lifting lug design. Search "eng-tips" for many threads about this topic.

I would like to hear the thoughts of others on this topic

MJCronin
Sr. Process Engineer

RE: Does design of lifting lug have some standard practice?

You may want to review DIN 28085 and/or DIN 28086.
Not sure if the PIP standards also might have something for this.

RE: Does design of lifting lug have some standard practice?

Read UG-54(a)if designed to ASME Section VIII Div. 1, All vessels shall be so supported and the supporting members shall be arranged and/or attached to the vessel wall in such a way as to provide for the maximum imposed loadings (see UG-22 and UG-82).

Test Weight.

RE: Does design of lifting lug have some standard practice?

Have you reviewed ASME BTH-1 (Below-The-Hook lifting devices)? I believe it covers lifting lugs.

RE: Does design of lifting lug have some standard practice?

BTH-1 doesnt cover what youre looking for. The OP is looking for a lug (assuming welded to a vessel), whereas BTH is for devices which are under the hook. A lug is not a device, but an integral part of the vessel. It would be strange that BTH would cover lugs; consider you have a vessel which is finished and needs to be lifted. Someone takes BTH at hand, and then finds out the lugs on the vessel dont meet the BTH Code requirements. That wouldnt make sense.

RE: Does design of lifting lug have some standard practice?

Why not use trunnions?
My previous response to a similar question:
IMO working with an experienced good engineer who has done this type of work time and time again in the past without issues is my recommendation.
Books and theorey are all good but books do not cover all the things you may come across in reality.

RE: Does design of lifting lug have some standard practice?

See "Pressure Vessel Design Manual 4th Ed. Dennis R. Moss and Michael Basic"

Regards

RE: Does design of lifting lug have some standard practice?

'' pressure vessel handbook '' by Eugene F. Megyesy may help full too

RE: Does design of lifting lug have some standard practice?

I use the aforementioned Denis Moss myself. But you don't necessarily have to buy it. I allow fabricators to use any method that is based on sound engineering and takes account of all of the below...
(Other manufacturers' in-house methods will essentially all follow the same basic Good Engineering Practice.)

Check shear through the shackle hole; shear in the proposed shackle (or you could consult a catalogue); shear in weld; bending in lug and bending in the weld. If there is a doubler pad check shear and bending in the weld and bending in the plate (a bit nebulous that one). Use a snatch factor (2.0 would be good). And make sure you design for the full lift (e.g. horizontal to vertical). Make sure you know whether the vessel is to be lifted dressed or not. Lugs will always also be subject to a certain amount of 'lateral' stress (into or away from the vessel) especially if no spreader beam is used, so it should be taken account of, even though it will be a bit of guesswork. Use WRC 107 (for manual calcs - WRC 537 if commputerised) to check the local loads on the shell.

RE: Does design of lifting lug have some standard practice?

Litfing lugs -or trunnions- in pressure vessel shall comply with ASME BTH-1 Design of Below-the-Hook Lifting Devices, where the nominal design factor Nd= 2 (min.) for category A.

Regards

RE: Does design of lifting lug have some standard practice?

Lifting lug / trunnion shall pass a load test before hydrostatic test.

Regards

RE: Does design of lifting lug have some standard practice?

Afaik, there’s no mention of BTH-1 in VIII-1.

RE: Does design of lifting lug have some standard practice?

r6155:
Where in ASME BTH-1 or even in ASME B30.20 does it mention the design of pressure vessel lifting lugs or trunnions? I cannot find this.
Also - please let me know how you load test lifting lugs and trunnions, say for example a 40m long column (130feet) weighing say 100Ton.
It is not practical and I have never seen load tests done on pressure vessels or columns.
The design is proven and NDE applied both in the welds and in the vessel or column plate.

RE: Does design of lifting lug have some standard practice?

Look at procedure 7-6 from the Pressure Vessel Design Manual by Dennis Moss.

Sometimes using lifting trunnions instead of lifting lugs might be a better idea because the lifting lugs have several issues:

If they are welded to the top head - they can be affected by forces perpendicular to their major plane - i.e. relatively easy to bend or break them.
So the usual practice for lugs of many plants is to have them welded to the shell which usually makes them very long so extra gussets need
to be incorporated in the design to keep them rigid. (I am attaching examples).

If you're not allowed to grind flush the circumferential seam under the lug or weld perpendicularly through it for some reason,
then a compensating pad becomes mandatory. Sometimes the heads could be thicker than the shell and you would need a pad too.
http://www.ossrs.com/_images/headers/projects.jpg

Lifting using the shell cylinder reduces the risk of deforming the head. You would also need to check the stresses in either of them (depending on which approach you use)

Another option is to have the lifting lug welded to a temporary flange cover as shown here:
https://ars.els-cdn.com/content/image/1-s2.0-S0308...

but this is rarely used.

Vertical vessels are usually lifted in place using two cranes. So you'd need two lifting lugs at the top and a tailing lug somewhere in the lower section of the shell cylinder or the cone
in order to execute the lift properly.

All lifting devices should be checked for lifting from horizontal to vertical: 0 deg to 90 deg orientation.

Also the minimum typical safety factor for on-shore applications would be about 1.5. SF=2 and above should be considered for off-shore applications.

If this is an actual job and you're not sure what you're doing - ask someone with experience to show and explain. Lifting devices are critical.




RE: Does design of lifting lug have some standard practice?

CuMo, excellent post. Just a small remark; please remove the link to Moss' book, even though it's on Google and youre not physically sharing it; youre still directing to copyrighted materials. That's not allowed by the site. Apart from that, a star for you.

/edt: BEHANAN - are you actually reading this? You seem to make some dubious posts, but (so far) never reply to any of them. Whats your intent with these questions?

RE: Does design of lifting lug have some standard practice?

https://www.eng-tips.com/viewthread.cfm?qid=11039

https://www.eng-tips.com/viewthread.cfm?qid=87971

https://www.eng-tips.com/viewthread.cfm?qid=165599

https://www.eng-tips.com/viewthread.cfm?qid=273125

https://www.eng-tips.com/viewthread.cfm?qid=291061

... and of course, the thieves at scribd.com have been busy by stealing and selling the knowledge of others ....

https://www.scribd.com/document/258587693/Design-o...

It has become much more difficult to find authentic and valid technical papers since these thieves (yes i said that) have set up shop ....

MJCronin
Sr. Process Engineer

RE: Does design of lifting lug have some standard practice?

BEHANAN, as r6155 mentioned, I'd recommend you to follow "Design manual 4th edition by Dennis R Moss" its one of the widely recognized book with detailed and comprehensive methods for Design/Analysis. And, don't forget evaluate the stress induced on shell / head due to rigging / lifting loads. In case of horizontal lifting, you'd also have to evaluate the bending stress at the center of shell due to rigging / lifting.

RE: Does design of lifting lug have some standard practice?

I speak about load test. Design calculation is clear in the books.

See http://www.hse.gov.uk/pubns/priced/loler.pdf

Lifting Operations and Lifting Equipment Regulations (LOLER) 1998: Open learning guidance
Regulation 4(b): the load being lifted

This part of the regulation is about ensuring that the parts of the load that become connected to the lifting equipment during lifting operations are sufficiently strong. Examples are lifting lugs welded in place to facilitate lifting, jacking or lifting points.
You need to know that:
- lifting points form part of the load;
- routine checks need to be made of the condition of lifting points;
- it may be appropriate to test the strength of lifting points such as welded lifting lugs.

Examples of lifting points include:
- lugs that are welded onto a steel beam before it is lifted, and that are removed afterwards;
- permanent fittings such as those on a skip which may often be lifted.
Key terms
Part of the load: Includes anything which connects the load to the lifting equipment and is lifted.

Regards

RE: Does design of lifting lug have some standard practice?

ASME BTH is not a required code for lifting lugs, but some of the design checks in it can be applied directly to lifting lugs, so it is a useful reference, despite the lugs not fitting the exact scope of the standard. Otherwise, the various vessel books as mentioned.

RE: Does design of lifting lug have some standard practice?

roca, proof load testing of lifting lugs are a common practice
- you hire a certified third party to perform the load test
- they'll attach your lugs to blocks of steel / concrete / hydraulic loads (calibrated loads)
- the lifting engineer will make sure that the lug is oriented at its critical position as per your rigging drawing / design
- they'll inspect the lug for tear & deformation post lifting and they'll issue a certificate with a safe working load (your design load)
- Test load & UT requirements vary as per local safety regulations / client requirement.

One of my client even asked us to demonstrate the lifting (this is for a Skid unit in its assembly condition)with a third party witness

RE: Does design of lifting lug have some standard practice?

balamurugan02
I hope our colleagues are convinced with your information. Thank you.

Regards

RE: Does design of lifting lug have some standard practice?

Nowhere in the OP's 1st post I see a mention that his lugs are detachable. I therefore assume they're to his vertical vessel. just out of curiosity, how do you physically proof load test a welded lug on an 18 ton vessel using

Quote (balamurugan02)

blocks of steel / concrete / hydraulic loads (calibrated loads)

RE: Does design of lifting lug have some standard practice?

XL83NL
We tested a lifting lug with 36 tonnes load by taking support from the head it was attached to.
I designed a jig which would brace two hydraulic jacks which then pushed against a cross beam and an opposing lifting lug.
It was a very clever approach as the dish was spherical and had some attachments that didn't make it easier.

RE: Does design of lifting lug have some standard practice?

CuMo; I stand corrected. For the scope we deal with, this is however never performed on the lugs that are welded to the vessel. But then again, our vessels usually don’t weigh (empty) more than a few metric tonnes, say max 3 or 4.
We’re in the EU, so BTH-1 (even if we design to VIII-1) is not known. EN standards would make more sense.

RE: Does design of lifting lug have some standard practice?

I mentioned this just for information. Usually clients who ask for proof load testing on main lifting lugs are happy to lift the vessel empty.
But this is only usually possible for horizontal vessels where the shop cranes are sufficiently high enough to perform the lift.
I think we might have had cases where we had to proof load test to 1.5 times the empty weight of a horizontal vessel but then it's easy to fill with water.

RE: Does design of lifting lug have some standard practice?

(OP)
austsa MJCronin XL83NL oknow Geoff13 roca r6155 AB53Mech Mr. Hankey r6155
CuMo JStephen balamurugan02 r6155
Thanks to all the persons for replying to the posts and contributing their precious time. I am very new to the engg tips as well as BPVC , I dont know to thank individually by selecting the post and replying it.
Well, I have followed Dennis MOss text for the standard practice.

RE: Does design of lifting lug have some standard practice?

balamurugan02
Please read my post and tell me how trunnions/lifting lugs are tested on a column with the example dimensions/weight I showed in my post.
I am fully aware of skids with structural bases being load tested as these skids can be bolted down to the shop floor in some way or loaded up with additional weight and a pulling load put on the lug.

r6155
I am not talking about the examples you show - I am fully aware of this for skids and beams and Loler requirements as I am in the UK
I am talking about a circular vertical column that is built horizontally in the shop, 40m long and 100Te weight

I am very interested to see how you would both do this given that the top column lugs/trunnions and vessel shell will see different loads in the horizontal position than in the vertical position.
It will be impossible for vessel fabricators to load test the lugs/trunnions with the column in the vertical position - unless you know of fabricators who can actually do this?

Thanks in advance.

RE: Does design of lifting lug have some standard practice?

Roca..

Please tell us of the Standards, Codes, EN rules and regulations that require load testing of lifting lugs.

Desired Customer requirements ... don't count

MJCronin
Sr. Process Engineer

RE: Does design of lifting lug have some standard practice?

MJCronin
For the equipment I am asking about (a fabricated large column - which the guys above say can or are required to be load tested) - None as far as I am aware and have used in past designs

RE: Does design of lifting lug have some standard practice?

Please see again my post 20 Aug 19 14:35 LOLER 1998 Regulation 4(b)

CuMo:
avoid lifting lugs in horizontal vessel: use slings

Roca.
Tower in horizontal position: with crane shop lift 10-20 mm the tower with the two upper lugs, wait 10 minutes, lower and inspect. Repeat with one lug

Try to design vertical vessel without lifting lugs welded to pressure part. Several design use nozzle, see attached picture.

Regards

RE: Does design of lifting lug have some standard practice?

roca, in case of a column / a large vessel where you cant just fabricate the whole vessel and load test it in a shop, you just have to fabricate the shell course with the lugs / trunnions attached to it and test them separately (with hydraulic / mechanical load) its a matter of agreement b/w you and your client.

RE: Does design of lifting lug have some standard practice?

r6155 and balamurugan02
Thanks for your comments.
Never seen it done before for a vertical vessel either in pieces (as suggested by balamurugan02) or as a complete finished column, and I doubt I ever will.
Cheers

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