Standard A 106 and A105 for superheatre application 2

[workoholic]

We have a boiler superheater with 9-5/8" OD that must be replaced. I am just wondering if we could use seamless carbon steel A106-B for this application? The A178 is for superheater but it covers up to 5" OD. As well there is a reducer that I want to replace with A105.

 

[metengr]

What is your design steam temperature for this header?

Without knowing more information, I would say you could use ASME SA/ASTM A 106 Grade B material PROVIDED your design steam temperature is below 800 deg F.

This work will require someone that posses a valid National Board Certificate of Authorization to Repair or Alter Boilers and Pressure Vessels. This is most important to assure that the header is designed, fabricated and installed in accordance with the original code of construction.

 

[GenB]

If you are using A178 probably is rolled and sealwelded only so A106 since takes more temp and pressure could be even better but again you are modifying a vessel and the NB takes it seriously/or the Jurisdiction will, you may cointact your boler Inspector to see if he/she will allow the practice.
er

 

[workoholic]

I am just wondering if there is any specific standard or welding method for welding the Superheater Tube of the boiler specially when we have A106 Seamless Carbon Steel? Please advise

 

[metengr]

Yes, there is a specific construction code for boiler and pressure vessel design, it is called the ASME Boiler and Pressure Vessel Code. It contains various sections that pertain to design, fabrication, joining (welding), and construction of boiler and pressure vessels. All welding has to be performed using qualified welding procedures and welders under the requirements of Section IX of the ASME Boiler and Pressure Vessel Code.

The design of the SH header will be in accordance with ASME B&PV code. The actual installation of the replacement SH header requires a boiler repair contractor that has a Certificate of Authorization to Repair Boiler and Pressure Vessels issues by the National Board of Boiler and Pressure Vessel Inspectors.

By the nature of your question, I would recommend you seek advice from a boiler repair organization that does this type of work on a routine basis.

 

[GenB]

YOu are replacing a header and you may need a National Board certified R stamp holder, all repairs are to be per the NBIC Latest Edition.
er

 

[MJCronin]

worko...

You say you have a 9-5/8 inch OD header ??..??

You may not be able to find A106 (piping) materials in that odd diameter size. You may have to get a CS plate rolled to your requirements.

In the USA, A016 is produced in nominal piping sizes which would be 8.625 inch and 10.75 inch ODs.

Superheater service, you say.....Are you sure that the tube/headers will not see temperatures > 800F ???

What are the steam design conditions at the superheater outlet ?

Many of the boiler designs I have reviewed use low chrome-moly materials for the superheater tubes and headers even when the normal operating temperatures is less than 750F.....This material choilce is a matter of "insurance" for the boiler operator.......

There is, of course, a slight increase in overall boiler cost.

My opinion only.

-MJC