RE: [MW:10509] Lethal Service / ASME Sec VIII Div 1

Gentlemen,

 

 

Sour serive & lethal service are totally different terms. A sour service vessel can be of non-lethal.

 

Please refer below definitions extracted from Specification.

 

Wet Sour Service:  Following process streams containing water and hydrogen sulfide: i) Sour water with a hydrogen sulfide (H2S) concentration above 2 mg/L (2 ppm) and a total pressure of 400 kPa absolute (65 psia) or greater. ii) Hydrocarbon services meeting the definition of sour environments in  SAES-A-301, where the H2S concentration of 2 mg/L (2 ppm) or more in the water phase is equivalent to H2S partial pressure of 0.05 psia.  Sour crude systems upstream of a stabilization facility and sour gas upstream of a sweetening or dehydration plant are examples of such environments. iii) Hydrocarbon systems exposed to an environment with a H2S concentration above 50 mg/L (50 ppm) in the water phase, regardless of H2S partial pressure. (As per Aramco Specification)

 

Lethal Service are meant use of poisonous gases or liquids of such a nature that a very small amount of the gas or of the vapor of the liquid mixed or unmixed with air is dangerous to life when inhaled ( As per UW-2, ASME SecVIII, DIv.1)

 

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From: materials-welding@googlegroups.com [materials-welding@googlegroups.com] on behalf of Vino Varghese [vinopvarghese@gmail.com]
Sent: Monday, March 28, 2011 08:39 AM
To: materials-welding@googlegroups.com
Subject: [MW:10507] Lethal Service / ASME Sec VIII Div 1

Dear All,

 

We are maufacturing a U-Stamp Pressure Vessel in accordance to ASME Sec VIII, Div 1.

Service: Sour Service

 

Query: How can you differentiate between an Sour Service with Lethal Service?

All Lethal Service requires PWHT and 100% RT for butt welds for Pressure Parts.

 

Do all Sour Service are Lethal in Nature?

 

Regards

Vino - Doha

 

 

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