internal/external corrosion

[pdp123]

Hi All respected members,

Please let me know in general whether internal corrosion is more dangerous or the external one.

Regarding the piping industry internal one has more severe effect as the thickness calculations are based on Internal corrosion
and regarding the Pipeline industry the External one has more severe effect as this may reduce the life of Pipeline.

Please correct my understanding and share your valuable thoughts about this contradictory statement.

Thanks
pme

Hard Work with Smartness is the key to success

 

[SJones]

Who made the 'contradictory statement?' Do you think that a corrosive fluid conveyed by piping is not as corrosive in a pipeline under the same conditions? Is this a coursework question?

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[pdp123]

I also do not think but as a general statement which type of corrosion is more governing.
Internal or External one and Why?

Appreciate your quick response.

Hard Work with Smartness is the key to success

 

[weldstan]

Generally corrosion allowance and alloy choice is bone by fluid transmitted. The use of coatings and Catholic protection mitigates external corrosion to a level that is not or only mildly influential in determining corosion allowance.

 

[newerbee]

Well, this will be a very general statement but all depends on what your internal and external conditions are. Is it dry gas inside and at atmospheric conditions outside? Or is it highly corrosive fluid line subsea? What are the operating conditions etc? What is the material you are using?

As you can see your question can not be answered directly.