Copper ferrules in fire tube boilers and related code(s)?

[BobbyLee]

I can use any help available right now...am in a debate with a fellow engineer about the use of copper spacing ferrules on a whole boiler retube (firetube low pressure steam)...I have been under the impression for the past 18 years I have been in this field that copper ferrules were only to be allowed by code for temporary fixes until permanant repairs can be made...ie, using steel ferrules when or where neccessary....

please help solve this debate...and is there any such code from ASME et al that may be applicable...

Thank you so very much!

Bobby Lee
CEE Metro Log Reading LLC
Chief Engineer Willoughby Condos CC MD

 

[metengr]

The code that you refer to is the National Board Inspection Code (NB-23) for firetube boiler repairs. I am not aware of any "temporary repairs" allowed or permitted by the NBIC, plain and simple.

I would not recommend the use of copper ferrules. The ASME Boiler and Pressure Vessel Code limits the use of copper and brass at 450 deg F due to a significant drop in tensile and yield strength above this service temperature.

 

[deanc]

The use of Copper Ferrules has been common practice for years. This is used in Firetube boilers(old and worn) when the tubeholes have become oversized from multiple tube replacements. It is preferable to overexpanding the replacement tube. It was also common practice for new boilers in the Railroad Locomotive,typically the firebox side.

Be careful:
1.Temperatures-as metengr says above.
2.Check for cracks in the sheet...firechecks.
3.Sand the hole,sand the od of the ferrule and roller expand in place to get a fit for the tube.
4.Sand the id of the ferrule and the end of the tube.
5.Insert and expand. Be careful not to have copper exposed in case you seal weld. It is better to bead then seal weld-I think.

Make you you get this OKed with the powers that be before you start.

Would not recommend steel ferrules as such(cracking when expanded). Think this would be getting into more of a welded repair. If your sheet is that bad---should replace it.

 

[GenB]

Copper ferrules are standard in FT repairs; lately steel ferrules are being used because the low temp of copper,
I have not heard of cracks on the steel ferrules,
It is my believe that the ferrules have be of materials that can be rolled as are the same tube materials to avoid cracking.ER