Cast Iron in Hydrocarbon Service under B31.3

[CSGWB]

In ASME B31.3 Para 323.4.2 Specific Requirements, Ductile Iron is separated from other Cast Irons with respect to permissible design temperatures.

Para 323.4.2 (b)(1) then goes on the note that Cast Iron should not to be used aboveground within process unit limits in hydrocarbon service above 300F nor at gage pressures above 150PSI.

Does the reference to cast iron in Para 323.4.2 (b)(1) include or exclude ductile iron?

Your assistance is appreciated.

Craig

 

[NozzleTwister]

Ductile Iron is not included with Cast Iron in the reference that you sight.

My experience has been that ductile iron and cast iron components are typically limited to utility services and steel is the perfered choice for hydrocarbon service.

NozzleTwister
Houston, Texas

 

[metengr]

If you read section 323.4.2 in the 2004 edition of B31.3, ductile iron is treated separately as either ferritic (non-austenitic) or austenitic in paragraph a) . If you do not have austenitic ductile iron, you have ferritic ductile iron and are limited to service temperatures of -20 deg F and 650 deg F for pressure containing parts.

PLEASE NOTE
As with any code or standard, these are considered minimum requirements for safe service of components under pressure. Actual selection of material is based on engineering principles and judgment - which the code cannot provide.

 

[CSGWB]

Thank you NozzleTwister and metengr for your assistance.

Craig

 

[MJCronin]

CSGWB.....

As a side note, I hope that you are aware of the sorry history of cast iron valves in steam piping systems.

ASME B31.1 contains warnings and limitations on the use of such materials in piping systems subject to severe theremal shock (like when a steam system is started up).

Aside from systems that are never subject to any real thermal transients, I would always select forged or cast steel valves.

See this link:

http://www.kirsner.org/pages/forensicResAlt.html

Trevor Kletz, the UK "godfather" of process safety and chronicler of disasters discusses these failures in his book "What went Wrong?"

Gimmie a star.....


-MJC