Corrosion/mechanical factor ASME B31.3 2

[mascar]

Hy everybody.
Which values of mechanical factor do i have to take in consideration in the ASME B31.3 formula for pressure design of straight pipe? I didn't find any table or reference in that code. Is there any other ASME code to take in consideration for the mechanical/corrosion factor?

Thanks in advance for your replies.

 

[JohnBreen]

Hi mascar,

B31.3, paragraph 304.1.1 requires you to consider all the possible causes for the effective wall thickness to have been reduced. The possibility of erosion and corrosion are obvious. One possible "mechanical" effective pipe wall reduction is seen in piping systems that use proprietary joints that require grooving the pipe wall near the mechanical joint. The effective wall thickness will be reduced by the depth of these grooves. Similarly, threading pipe for connections also reduces the effective pipe wall thickness. These examples are shown in paragraph 304.1.1 (b) in the definition of the factor (c).

Regards, John.

 

[Farouk1001111]

what asme b 31.3 for

 

[JohnBreen]

Hello,Farouk1001111

The ASME B31 Code for Pressure Piping, B31.3, Process Piping was written with the intention of addressing the piping systems within certain types of plants including oil refineries, chemical plants, food and drug processing plants, loading terminals , bulk processing plants and others. It is the responsibility of the plant owner to determine which Code shall be applied.

The ASME B31 Code for Pressure Piping includes specific “books” for various piping applications. The Code is dynamic and the “sitting committees” work at keeping the Codes up to date with current standard industry practice – note, not “cutting edge”, not “trend setting”, not “latest and greatest" - rather current standard industry practice. The B31 Codes are not the final word, only the latest word.

The history of the B31 Code is very interesting. In 1926 the American Standards Associations, ASA (forerunner of ANSI) initiated project B31 to develop a pressure piping Code. The resulting document, "American Tentative Standard Code for Pressure Piping, ASA B31.1 was issued in 1935.

During the long history of the B31 Codes various “book section” numbers were assigned for development. Some of these documents were developed but not used as the work was pulled into another “book”. Others of them were withdrawn when superceded by another document. For completeness I present the following list of B31 “projects” and Codes:

B31.1 – Power Piping
B31.2 – Fuel Gas Piping, WITHDRAWN superceded by ANSI Z223.1
B31.3 – Process Piping, (formerly Chemical Plant and Petroleum Refinery Piping)
B31.4 – Liquid Hydrocarbon Transportation Piping (for example oil cross country pipelines)
B31.5 – Refrigeration Piping
B31.6 – Chemical Plant Piping, never issued as a separate document, folded into B31.3
B31.7 – Nuclear Power Piping, WITHDRAWN, superseded by ASME Code, Section III
B31.8 – Gas Transportation Piping (for example cross country gas pipelines)
B31.9 – Building Services Piping (for example office building hot water heating and air conditioning)
B31.10 – Cryogenic Piping, never issued as a separate document, folded into B31.3
B31.11 – Slurry Transportation Piping (for example cross country coal/water slurries)

And the new B31.12 Hydrogen Piping Systems, which is under development and has not yet been issued.

The various ASME B31 Code Committees will be meeting in Seattle, WA, from September 17 through September 21, 2007.

Regards, John.

 

[Gator]

The various ASME B31 Code Committees will be meeting in Seattle, WA, from September 17 through September 21, 2007.

I hope to see you there, John.

Paul
Piping Design Central

 

[JohnBreen]

Hi Paul,

Yes, it looks as though I will actually be in the USA at meeting time. This will be my 31st year of attending meetings.

Regards, John.