Superheater Header Painting

[ashaari]

Hi guys.

I'm doing a superheater assembly replacement for my gas-fired power boiler. When the superheater assembly arrived at site, I found that there are traces of rust all over the superheater header. I've been advised to apply high-temp painting on the superheater header. Is it a normal practice to do that? Is it mentioned in any applicable codes (e.g ASME I or VIII)? How do I assess whether I need to paint the header or otherwise?

According to the fabricator, I don't need to apply the paint as we will apply castable surrounding the header. Also, since the superheater assembly is already complete, it's difficult to perform blasting on the header since all the tubes have already been welded, thus little access to the middle of the header. Is it OK just to power brush?

My superheater tube material is A213-T22, and the steam temp inside the assembly is 400 deg C. I'm not sure of the superheater header material as I don't have the datasheet with me now. Appreciate your comments, thanks.

 

[metengr]

ashaari;
You have absolutely no issues with surface rusting of this grade of steel. You can simply power brush the rust off before you use castable refractory or leave it alone. There is no harm once you place it into service. I would not waste money or resources to paint this header.

 

[athomas236]

ashaari,

I agree with metengr.

We do specify that superheater headers and tubes should be painted but this is just to prevent corrosion during transport to site and storage at site.

Regards,

athomas236

 

[rmw]

And I'll make it a third. Where that header and SH assembly is going to live the rest of its life, it won't care if it is painted or not. Frankly, what paint that is there won't be there very long after first fire.

rmw

 

[ashaari]

Thanks ppl for the feedback and reassurance.

 

[mizzoueng]

+1 on all comments, but I do want to add another.

If the header is on the back side of the water wall, it is not totally uncommon to coat the header in a red oxide primer prior to insulating. Once the unit is online and rolling at base load not much of that red oxide will be left, but it does help somewhat to protect the header during transport and installation.