Aerial Cooler Header Box in Lethal Service
Aerial Cooler Header Box in Lethal Service
(OP)
RE: Lethal Service
I went through the threads and also examined ASME VIII-1 UW-2(1)(c) - and I am still not sure whether aerial cooler header box joints can be made as Cat C (corner joints) with 100%UT or they have to be as per Figure UW-13.3.
I went through the threads and also examined ASME VIII-1 UW-2(1)(c) - and I am still not sure whether aerial cooler header box joints can be made as Cat C (corner joints) with 100%UT or they have to be as per Figure UW-13.3.





RE: Aerial Cooler Header Box in Lethal Service
However, the fig. UW-13.2 is for the header boxes designed to Div. 1.
gr2vessels
RE: Aerial Cooler Header Box in Lethal Service
Process fluids contain H2S. We would like to have a design to ASME VIII-1.
Is it OK to assume that joints for rectangular boxes (I'm talking about Div 1 design) can be 100% UT'd in lieu of 100% RT? Will that satisfy the requirements of UW-2?
RE: Aerial Cooler Header Box in Lethal Service
By the way, is it wet sour service or is lethal service?
Cheers,
gr2vessels
RE: Aerial Cooler Header Box in Lethal Service
My understanding is that Para UW-2(a)(1)(b): "All joints of Categories B and C shall be Type No. (1) or No. (2) of Table UW-12." effectivelly prohibits type "C" weld joints(standard corner weld joint) on header boxes. In other words, hub type joints are mandatory as shown in FIG. UW-13.3.
I would appreciate any other comments that you might have.
Regards,
RE: Aerial Cooler Header Box in Lethal Service
See Code Case 2235 (Use of Ultrasonic Examination in Lieu of Radiography) if this is applicable to your case.
http://www.sonotronndt.com/pdf%5CASME.pdf
Check with your AI and jurisdiction if this is acceptable.
RE: Aerial Cooler Header Box in Lethal Service
Thanks for the Code Case. The only outstanding issue is than whether the tubesheets and plugsheets have to have a hub (i.e. for joints to be butt welded) as per Fig UW-13.3.
I will definitely check with the AI as well.
Regards,
RE: Aerial Cooler Header Box in Lethal Service
My understanding of UW-2(a)(1)(b) is the same as yours. Category C joints for box headers in lethal service should only be butt weld joints (Type 1 or 2). Therefore, corner weld joints (Type 7) are not allowed for box headers in lethal service.
If your company is the User, somebody in your organization must verify if the exchanger is really in "lethal service". As you may have already read in UW-2(a), "...it shall be the responsibility of the of the user and/or his designated agent to determine if it is lethal. If determined as lethal, the user and/or his designated agent shall so advise the designer and/or Manufacturer."
RE: Aerial Cooler Header Box in Lethal Service
Thank you!
RE: Aerial Cooler Header Box in Lethal Service
I have checked out other countries classification and the conclusion is identical;- the wet sour service is classified very harmful liquid to human, but not lethal.
I believe that you should look for the hazard classification of the H2S (in Solution and Liquefied) around the world, to build your position.
Cheers,
gr2vessels
RE: Aerial Cooler Header Box in Lethal Service
Thank you veru much!
RE: Aerial Cooler Header Box in Lethal Service
Cheers.
gr2vessels
RE: Aerial Cooler Header Box in Lethal Service
For Alberta,Canada, the following are some interesting info/links about H2S:
http
http:/
H2S concentrations above 300 ppm is lethal.
When I was in college, we had a field trip to a refinery. While touring the plant, I sensed the smell of rotten egg. I asked our guide what the smell was and he said it was H2S coming from their Sulfur Recovery Unit. The guide said that he preferred the smell of rotten egg than not sensing (smelling) H2S. He said that if you are exposed to H2S and there is no smell, you could become unconscious or just drop dead. That was my first enlightenment about H2S.
RE: Aerial Cooler Header Box in Lethal Service
Thank you for the info!