Removal of Lifting Lugs and Trunnions 1

[AK8824]

In a middle-eastern refinery project, client specification calls for removal of Lifting Lugs and Trunnions after erection. As would be expected of contractors, they are seeking Waiver against this requirement. The reason put forth is that there is no value in removing them.

What is industry practice in this regard?

Any help would be appreciated.

Thank you.

 

[RVAmeche]

I've never heard of them being removed. When the equipment eventually needs to be replaced you'll be glad they're there. Why does the client want to require removal?

 

[MJCronin]

I have specified and reviewed many ASME Vessels, heat exchangers and other components.

There is no reason to remove these lifting lugs and padeyes ...

The client must have a reason for his demands and not point to an old specification and say "It says so here !!"


MJCronin
Sr. Process Engineer

 

The only problem I can see with leaving the lugs on would be interference with vessel insulation.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[XL83NL]

Or unnecessary cold spots

 

[Trestala]

We've had equipment where trunnion and lifting lug was removed mainly because of cold insulation.

 

[MJCronin]

IMHO, I have never believed the "cold spot" justification.... In other words, its bad because I say its bad

The cost of existing lug removal and the lost of ability to easily remove the equipment at a future date FAR outweighs the additional cost of a little creative insulation work.

Why is this even a topic of discussion ???

MJCronin
Sr. Process Engineer

 

[Dhurjati Sen]

Dear MJCronin,

Completely agree with you. Many of these "Client specifications" specially in the middle-east are in need of urgent revision.

Regards.

DHURJATI SEN
Kolkata, India

 

[r6155]

1) If the trunnions are left installed then they should be examined before future hoisting.

2) If horizontal vessel is mounted on skid, the lifting lugs shall be cutted below of lifting hole. The skid shall be lifted with your own lugs.
Avoid lifting lugs in horizontal pressure vessel.

Regards

 

[AK8824]

Thanks all of you for your valuable input.

MJCronin,

This requirement comes from Shell DEP 31.22.20.31, Pressure Vessels (Amendments/supplements to ASME Section VIII Division 1 and Division 2), para 4.15.6 of Version 32, which reads:

Lifting lugs and trunnions shall be removed after erection of the vessel is complete, unless otherwise specified by the Principal. Removal shall be such that lug or trunnion is completely covered by insulation on vessels that are insulated.

That is the reason I brought it up to the notice of this forum.

It seems the majority of contributors have not applied such requirements. In fact, even I have never used this although I have worked on a Shell project in Alberta.

Thank you.

 

[DBreyer]

I would imagine removal is mainly required for mitigating CUI in insulated vessels.
I have seen quite a couple of cases were CUI was found very localized around lifting lugs as they can create areas that trap water. Additionally they quite often protrude the insulation creating ways for water to penetrate the insulation cladding.



Daniel Breyer
Inspection Engineer

http://lnkd.in/dFcQA-w

 

[MJCronin]

AK8824:

Explain the rational for this expensive removal... as you understand it

Yes, Yes ... we all understand that the ORIGIN of this removal is a spec copied from a spec copied from a spec ..

Why, in your opinion, is this necessary ???

MJCronin
Sr. Process Engineer

 

[AK8824]

MJCronin,

I learnt from some friends that Ear-type lifting lugs typically suffer from the problem of corrosion due to trapped water between the lug and the vessel. There are more chances of corrosion under insulation in the trunnion region. As the trunnion projects like a fin on the vessel, there will be a possibility of heat loss.

AKumar

 

[mk3223]

I saw the lifting lugs read removed on the high temperature duct pipe from the reactor after installation. I believe it can be based on the operation experience, and justified per agreement from Engg and Mgmt, as well.

 

[MJCronin]

AK8824

You state: "the problem of corrosion due to trapped water between the lug and the vessel.".... You mean to tell me that the lug is NOT WELDED ALL AROUND ? .... This is a defective design, unlike anything in common use

I envision this as a "padeye lifting lug"

What TF are you talking about ? ... Show examples or pictures

"I learnt from some friends".... "some people told me" .... "A guy at work once told me"

Please... No mid-eastern heresay "Whatdoyathink" engineering ....

This thread is a waste of time ....




MJCronin
Sr. Process Engineer

 

[r6155]

Pressure Vessel Design Manual, by D. Moss 4TH Ed.
Lifting attachments may remain on the vessel after erection unless there is some process- or interference-
related issue that would necessitate their removal.


API 571
Examples of locations where CUI can occur are listed below:
1)……
.
2) Equipment designed with insulation support rings welded directly to the vessel wall (no standoff); particularly around ladder and platform clips, and lifting lugs, nozzles and stiffener rings.

Regards

 

[AK8824]

Hi r6155,

Thanks for quoting the reference from Pressure Vessel Design Manual, by D. Moss. 4th Ed.

In fact, I am in agreement with you and others. What is noteworthy is that the requirement of lifting lug removal was not there in Shell DEP in Version 20. But it was added in Version 32. Your post is very helpful.

Cheers!

 

[Stevo777]

I think it's probably because some site operators have ridiculous requirements in that any lift points must be certified/registered/documented and routinely checked. If you cut them off this requirement goes away.