Hot-tapping chlorinated lines

[a7992]

I was asked to give choride content limits and temperature limits for welding chlorinated lines in-service. As far as I know, this should not be done at all in-service. Are there situations where it is ok to hot-tap chlorinated lines? If not, are there any codes/documents related to hot-tapping chlorinated lines? There may be other impurities in the line which is another thing I am concerned about. Any info on this wold be great!

 

[SJones]

'Chlorinated' implies water lines? What is the specific concern regarding the effects of residual chlorine at ppm levels in the system? What is the specific concern regarding chlorides and temperature limits? Is somebody worried about stress corrosion cracking of stainless steel under the short term exposure to elevated temperatures from welding?

Please elaborate upon the specific scenario to be considered including operating conditions, temperatures, fluids and materials. Your first document of reference should be API RP 2201.

Steve Jones
Materials & Corrosion Engineer

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

 

[a7992]

Yeah, I was worried about the effects of residual chlorine causing SCC. Is that something I should not worry about? Basically, I've been asked to say under what operating conditions it is ok to weld on chlorinated lines. They are looking to know what ppm of chlorides and at what temperature it is ok to weld on chlorinated lines while in service. The materials can be either carbon steel, 304 or 316 SS.