ANY ONE CAN TELL ME WHAT ARE THE MINIMUM REQUIRMENT FOR LATHEL SERVICE {SOUR} VESSEL DESIGN CRITERIA.
WHERE I CAN START.
IF THE SERVICE CONDTION ARE HIC,SSC , ETC.
WHAT ARE THE QWP FOR THAT VESSELS .
ARE HARDNESS TEST AND MATRIAL SELCTION COVER THE DESIGN REQUIRMENT ? NACCE MR0175 OR SOME THING MORE

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Hasan,

Is your query regarding lethal service or sour service?

Sour service may or may not be lethal and it depends on H2S concentration whether to call it a sour and/ or lethal service.

Other services which do not contain H2S (non sour) may also be lethal such as chlorine, ammonia etc.

Refer UW2 for lethal service requirements.

Testing requirements such as HIC/ SSC are based on the process media and based on metallurgy requirements and not on lethal service requirements

NACE MR 0175 is now revised as ISO 15156 and is for materials for use in H2S containing envinorment and does not specify requirements for lethal services.

Regards

Thank you sanjeev Im looking for only design criteria for only soure service specially ,material selction ,welding procesdure or some any other new code requirment which makes it diffrent from regular vessels.
but now after your reply it seems to me its is very close to regular vessel except the (HIC,SSC or H BLISTRING OR other corrosion component consideration )condtion:D

REGARDS

HASAN

You should check UW-2.

The biggest effect is full RT, mandatory PWHT and the requirement to design all Category B and C welds as Type 1 or 2 from UW-12.
This means, WE flanges and WE tubesheets and WE flat heads are mandatory.
Take care.

DK

Check ISO 15156/ NACE MR 0175 for sour service requirements.

Main requirement for the material in sour service is limitation on hardness.

CS/ LTCS material have some limitations on S/ Ni contents.

HIC/ SSC etc are not a mandatory requirement as per the ISO 15156 and leaves it to the descrition of metallurgist based on severity of the service.

PWHT is again not a mandatory requirement and linked with the hardness limitations.

SS/ DSS are not a pre qualified materials beyond a certain temperature and based on Chloride content in the service media(I think 60 deg C is the max temp limit for SS irrespective of Cl content and to be qualified based on laboratory/ field experience if to be used out side the limit specified in NACE)

Again wish to highlight that suor service may or may not be lethal and depends on H2S concentration to call it lethal or not.

Please refer UW 2 it it is classified under lethal service also.

Regards

Dear Dr. Koelbl,

What does "WE" mean? I know weld neck flange. Is it weld end flange ans so on.

Yes, Welding End Flanges are the same asWelding Neck.

DK

Dear Sirs,
when the sour service is considered lethal service? What is (if there is) the H2S concentration limit where a fluid passes from not lethal to lethal?

Thank you.
Regards
AndreaO

It is the User who has to establish it. It is not the manufacturer's responsibility
Mauro

Thank you for your prompt reply,
it is clear the User responsability, but just to understand, I have a specification that defines H2S content upto 1 MOL% alongwith 6% Aromatics, can be this concentration considered as lethal service? Can I find literature that define this limit?

Regards
Andrea

Andrea,

As stated before, the USER / OWNER is responsible to specify Lethal Service when applicable.
The Jurisdiction at the location of installation may or may not have specific requirements as to what is considered Lethal.
Very often the User designates an Engineerign company to specify the vessel, in this case the Engineering contractor shall specify.

DK

You can refer to OSHA for the various exposure limits (permissible exposure limit, max peak exposure, immediately dangerous to life and health etc).

Most of the time definition of Lethal is covered by the Juridiction at location of installation and may differ for each location.

To make life simpler and unambiguous for every one, my present company standard practice is to consider it lethal for pressure equipment if it falls under sour service category. may be overkill some time but no ambiguity.