Does design of lifting lug have some standard practice? 2

[behanan]

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 ?

 

[JStephen]

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.

 

[balamurugan02]

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

 

[r6155]

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

Regards

 

[XL83NL]

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

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

 

[CuMo]

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.

 

[XL83NL]

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.

 

[CuMo]

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.

 

[behanan]

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.

 

[roca]

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.

 

[MJCronin]

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

 

[roca]

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

 

[r6155]

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

 

[balamurugan02]

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.

 

[roca]

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