Lethal Dilema 3

[bmoorthy]

We are EPC contractors. Our client (USER) provides the process data sheet.

This data sheet does not indicate the Service is lethal service.
But the data sheet states that the Fluid is Sour and contains 12000 PPM of H2S.
Vessel Design pressure is 180 Bars.
Design Temperature: 193 Deg C
Fluid Specific Gravity, Flow rates and velocity ect are specified.
Full description of Fluid composition not in the data sheet of the vessle.
But is Hydro carbon.

Fluid is Gas Mostly and also little Oil + water mixture.

Process data along with pressure temperature ratings were sent to prospective Vessel manufactureres in UK, USA, Italy

The vessel Requires design certificaton and manufacturing certification and MRB certification by independednt third part certifying agency. If U Stamping and marking is offered in place of Design certification that is also acccepted since the U staming agency will undertake design verificaton and also under take inspections as per ASME.


Vessel Fabricator has the option to go
ASME or PD 5500.

1) Reputed manufacturer from Italy offer data sheet shows Under lethal service: NA. Design Certification offered.
Design as per PD 5500.
2) Another, not so reputed supplier, from Italy: Offer data sheets shows: Lethal Service: Yes. Design Certification offered, design as per PD 5500.
3) Another UK manufacturer : Offer data sheets shows: Lethal Service: Applicable. Design Certification offered, design as per PD 5500.
4)Another UK manufacturer : Offer data sheets shows: Lethal Service: Nil. Design Certification offered, design as per ASME Sec VIII Div 1. No U Stamp.
5)Another UK manufacturer : Offer data sheets shows: Lethal Service: Please specify.
Option 1) U stamp: ASME Sec VIII Div 1.
Option 2) No U Stamp but independent Design verification and inspection with third party
Option 3) PD 5500.Design verification and inspection with third party.
6)Another US manufacturer (Only one offer from US): Offer data sheets shows: Lethal Service: Yes. design as per ASME Sec VIII Div 1, U stamped.

A) Who is technically sound?
B) Who is ssupposed to define whether the equipment is in lethal service
C)If with out checking with the user i decide that the service is not lethal am i wrong.
D) If the above vessel is going to be installed in USA (Houston with U stamp),would it warrent Lethal service
E) if the above vessel is used in Noth Sea (Europe) eiher U stamp or Independent design certified to PED (PD 5500) would it warrent Lethal service.

 

[gr2vessels]

Hi bmoorty,
The lethal service is normally specified by the Client (refer UW-2). It is, however the Client's right to nominate the service in accordance with their local government requirements. In my opinion, 12000 ppm H2S is lethal service, regardless of the color of the operator's skin. Unfortunately, it also depends who the "User" is, I have seen worst than this in Oil and Gas projects, where one major Oil company has had little regard for the Nigerian workers safety all across the project, to put it mildly. Certified fabrication to any Code, ignoring the nominated 12000 ppm H2S is an insult to decency, regardless of the datasheet shortcoming on service nomination.
The U-stamp is not mandatory in most of the world (in some places is also meaningless), hence certified compliance with ASME VIII-1 is what the major insurance companies would normally require (design and fabrication).
Yes, the vessel installed in Houston, with or without U-stamp, would be classified and certified as operating in lethal service and fabricated/certified accordingly. Ditto for the vessel operated in North Sea area.
All my respect for the reputed or less reputed fabricators who took the initiative of nominating the lethal service, despite the inconsistency on the datasheet (I want to believe that it was an oversight from your Client...).
Cheers,
gr2vessels

 

[SJones]

Wouldn't it be better to formalise the question (and the answer) with the User rather than inviting speculative opinion on here?

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdoweb/

 

[metengr]

You need to discuss this with the vessel User/Owner and the Insurance/Inspection Agency that will insure the vessel.

 

[MJCronin]

bmoor.....

Suggest that you post this under the "boier and Pressure Vessel Forum.

I have always thought that the complex and bureucratic "Lethal Service" designation mess that has been propogated by ASME was a disservice to all.

If the various governments can promulgate various complex rules about medicines, drugs and emmissions, why cant they give us simple guidelines about which fluids must be deginated as lethal service ?

http://www.ast-forum.com/ast_forum_tree.asp?master=8378

-MJC

 

[stanweld]

bmoorthy
Under U-2, ASME VIII, Div. 1, "the User or his designated agent" (usually the Owner's Engineer or the designer of a process) is responsible for determining Lethal service - not the vessel Manufacturer. Jurisdictions may also specify Lethal service for specific process environments.