RE: [Man.Distr] LTCS pipes in higher dia?

1. NACE MR 0175 specifies materials for sour services. Does it specify materials according to the size range? The use of A333 Gr.6 pipe may be because of the following:

The minimum piping class temperature may be around zero degree Centigrade. For sizes above 6" may require higher thickness (greater than 24.5mm) for CS at the intended higher pressures, hence will be required to be impact tested in accordance with the Code (ref. Fig 323.2.2A ASME B31.3). By using impacted tested carbon steel like A333 Gr. 6 the design check for the impact testing can be avoided. I don't know the price comparison for (a) CS pipe with impact testing and (b) Impact tested CS A333 Gr. 6. Using A333 Gr. 6 may be cost and time effective.

2. The Flange acing shall be suitable for the intended service and for the gasket and bolting employed. Code does not prohibit RF flanges in 2500 ratings.

George

-----Original Message-----

From: Sajit Viswan [mailto:sviswan@tebodin.co.om] Sent: Wednesday, February 11, 2004 7:55 AM To: <a href="/group/PipingDesign/post?postID=NGuHehW0EC2r43HwW-LySoj9MWEQLAFzr3AcOeQSdiKEZvFhrCGAGI_Oxkve1PktjvSVNeWoI5v8DiODheTDds2dckQ">PipingDesign@yahoogroups.com</a> Subject: RE: [Man.Distr][PipingDesign] LTCS pipes in higher dia?

1. Is related to the SOUR service. The NACE MR 175 standard will explain the reason.
2. Should have been RTJ. Unless if it was to match existing RF flanges. Might be an error in the specification. If you find please tell the group.

Sajit

-----Original Message-----

From: t.r. vaddi [mailto:vteju2000@yahoo.com] Sent: Friday, January 30, 2004 8:30 AM
To: <a href="/group/PipingDesign/post?postID=NGuHehW0EC2r43HwW-LySoj9MWEQLAFzr3AcOeQSdiKEZvFhrCGAGI_Oxkve1PktjvSVNeWoI5v8DiODheTDds2dckQ">PipingDesign@yahoogroups.com</a> Subject: [Man.Distr][PipingDesign] LTCS pipes in higher dia?

Hi folks!!!!!
In some of the shell piping classes(eg 251440) i noticed that
1.Upto 6" A106 gr.B is specified .However above 8" A333Gr.6 (LTCS ) is specified.I wanted know the reason Why LTCS is required for sizes 8" and above. 2.The flanges are specified as RF (even in 2500# rating )
instaed of RTJ.Is RF better than RTJ in higher rating flanges?

rgards
VTRAO [Non-text portions of this message have been removed] Received on Wed Feb 11 02:02:00 2004